diff --git a/example/example.cpp b/example/example.cpp
index a97c3507..918d19b1 100644
--- a/example/example.cpp
+++ b/example/example.cpp
@@ -14,8 +14,9 @@ spdlog::logger *get_logger();
 int main(int, char *[])
 {    
     auto *l = get_logger();
-    l->info("HELLO  {}", "GA");    	
-    l->error("Some {}", "error");
+    l->info("HE LO ", "GA");    	
+	l->error("Some {} {} {}", "er or");
+    l->error("Some {} {} {}", "er or");
    
 
 }
\ No newline at end of file
diff --git a/include/spdlog/common.h b/include/spdlog/common.h
index f76aedea..275ea23b 100644
--- a/include/spdlog/common.h
+++ b/include/spdlog/common.h
@@ -9,22 +9,16 @@
 
 #include <atomic>
 #include <chrono>
-#include <functional>
 #include <initializer_list>
 #include <memory>
 #include <stdexcept>
 #include <string>
-#include <cstring>
-#include <type_traits>
-#include <unordered_map>
 
 #if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
 #include <codecvt>
 #include <locale>
 #endif
 
-#include "spdlog/details/null_mutex.h"
-
 #include "spdlog/fmt/fmt.h"
 
 #ifdef SPDLOG_HEADER_ONLY
@@ -75,6 +69,17 @@
 #define SPDLOG_FUNCTION __FUNCTION__
 #endif
 
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+#define SPDLOG_FILENAME_T(s) L##s
+SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
+{
+    std::wstring_convert<std::codecvt_utf8<wchar_t>, wchar_t> c;
+    return c.to_bytes(filename);
+}
+#else
+#define SPDLOG_FILENAME_T(s) s
+#endif
+
 namespace spdlog {
 
 class formatter;
@@ -86,7 +91,6 @@ class sink;
 using log_clock = std::chrono::system_clock;
 using sink_ptr = std::shared_ptr<sinks::sink>;
 using sinks_init_list = std::initializer_list<sink_ptr>;
-using log_err_handler = std::function<void(const std::string &err_msg)>;
 
 // string_view type - either std::string_view or fmt::string_view (pre c++17)
 #if defined(FMT_USE_STD_STRING_VIEW)
diff --git a/include/spdlog/details/async_logger_impl.h b/include/spdlog/details/async_logger_impl.h
index 88bd5e7c..d3676960 100644
--- a/include/spdlog/details/async_logger_impl.h
+++ b/include/spdlog/details/async_logger_impl.h
@@ -38,9 +38,6 @@ inline spdlog::async_logger::async_logger(
 // send the log message to the thread pool
 inline void spdlog::async_logger::sink_it_(details::log_msg &msg)
 {
-#if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
-    incr_msg_counter_(msg);
-#endif
     if (auto pool_ptr = thread_pool_.lock())
     {
         pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
@@ -119,6 +116,6 @@ inline std::shared_ptr<spdlog::logger> spdlog::async_logger::clone(std::string n
 
     cloned->set_level(this->level());
     cloned->flush_on(this->flush_level());
-    cloned->set_error_handler(this->error_handler());
+    cloned->set_error_handler(this->custom_err_handler_);
     return std::move(cloned);
 }
diff --git a/include/spdlog/details/pattern_formatter.h b/include/spdlog/details/pattern_formatter.h
index 3c38e762..3388743d 100644
--- a/include/spdlog/details/pattern_formatter.h
+++ b/include/spdlog/details/pattern_formatter.h
@@ -4,26 +4,23 @@
 //
 
 #pragma once
-#include "spdlog/details/fmt_helper.h"
+#include "spdlog/common.h"
 #include "spdlog/details/log_msg.h"
 #include "spdlog/details/os.h"
 #include "spdlog/fmt/fmt.h"
 #include "spdlog/formatter.h"
 
-#include <array>
 #include <chrono>
 #include <ctime>
-#include <cctype>
 #include <memory>
-#include <mutex>
+
 #include <string>
-#include <thread>
-#include <utility>
 #include <vector>
 
 namespace spdlog {
 namespace details {
 
+
 // padding information.
 struct padding_info
 {
@@ -49,64 +46,6 @@ struct padding_info
     const pad_side side_ = left;
 };
 
-class scoped_pad
-{
-public:
-    scoped_pad(size_t wrapped_size, padding_info &padinfo, fmt::memory_buffer &dest)
-        : padinfo_(padinfo)
-        , dest_(dest)
-    {
-
-        if (padinfo_.width_ <= wrapped_size)
-        {
-            total_pad_ = 0;
-            return;
-        }
-
-        total_pad_ = padinfo.width_ - wrapped_size;
-        if (padinfo_.side_ == padding_info::left)
-        {
-            pad_it(total_pad_);
-            total_pad_ = 0;
-        }
-        else if (padinfo_.side_ == padding_info::center)
-        {
-            auto half_pad = total_pad_ / 2;
-            auto reminder = total_pad_ & 1;
-            pad_it(half_pad);
-            total_pad_ = half_pad + reminder; // for the right side
-        }
-    }
-
-    scoped_pad(spdlog::string_view_t txt, padding_info &padinfo, fmt::memory_buffer &dest)
-        : scoped_pad(txt.size(), padinfo, dest)
-    {
-    }
-
-    ~scoped_pad()
-    {
-        if (total_pad_)
-        {
-            pad_it(total_pad_);
-        }
-    }
-
-private:
-    void pad_it(size_t count)
-    {
-        // count = std::min(count, spaces_.size());
-        assert(count <= spaces_.size());
-        fmt_helper::append_string_view(string_view_t(spaces_.data(), count), dest_);
-    }
-
-    const padding_info &padinfo_;
-    fmt::memory_buffer &dest_;
-    size_t total_pad_;
-    string_view_t spaces_{"                                                                "
-                          "                                                                ",
-        128};
-};
-
 class flag_formatter
 {
 public:
@@ -122,944 +61,26 @@ protected:
     padding_info padinfo_;
 };
 
-///////////////////////////////////////////////////////////////////////
-// name & level pattern appender
-///////////////////////////////////////////////////////////////////////
-class name_formatter : public flag_formatter
-{
-public:
-    explicit name_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        if (padinfo_.enabled())
-        {
-            scoped_pad p(*msg.logger_name, padinfo_, dest);
-            fmt_helper::append_string_view(*msg.logger_name, dest);
-        }
-        else
-        {
-            fmt_helper::append_string_view(*msg.logger_name, dest);
-        }
-    }
-};
-
-// log level appender
-class level_formatter : public flag_formatter
-{
-public:
-    explicit level_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        string_view_t &level_name = level::to_string_view(msg.level);
-        if (padinfo_.enabled())
-        {
-            scoped_pad p(level_name, padinfo_, dest);
-            fmt_helper::append_string_view(level_name, dest);
-        }
-        else
-        {
-            fmt_helper::append_string_view(level_name, dest);
-        }
-    }
-};
-
-// short log level appender
-class short_level_formatter : public flag_formatter
-{
-public:
-    explicit short_level_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        string_view_t level_name{level::to_short_c_str(msg.level)};
-        scoped_pad p(level_name, padinfo_, dest);
-        fmt_helper::append_string_view(level_name, dest);
-    }
-};
-
-///////////////////////////////////////////////////////////////////////
-// Date time pattern appenders
-///////////////////////////////////////////////////////////////////////
-
-static const char *ampm(const tm &t)
-{
-    return t.tm_hour >= 12 ? "PM" : "AM";
 }
 
-static int to12h(const tm &t)
-{
-    return t.tm_hour > 12 ? t.tm_hour - 12 : t.tm_hour;
-}
-
-// Abbreviated weekday name
-static const char *days[]{"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
-class a_formatter : public flag_formatter
-{
-public:
-    explicit a_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        string_view_t field_value{days[tm_time.tm_wday]};
-        scoped_pad p(field_value, padinfo_, dest);
-        fmt_helper::append_string_view(field_value, dest);
-    }
-};
-
-// Full weekday name
-static const char *full_days[]{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
-class A_formatter : public flag_formatter
-{
-public:
-    explicit A_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        string_view_t field_value{full_days[tm_time.tm_wday]};
-        scoped_pad p(field_value, padinfo_, dest);
-        fmt_helper::append_string_view(field_value, dest);
-    }
-};
-
-// Abbreviated month
-static const char *months[]{"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec"};
-class b_formatter : public flag_formatter
-{
-public:
-    explicit b_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        string_view_t field_value{months[tm_time.tm_mon]};
-        scoped_pad p(field_value, padinfo_, dest);
-        fmt_helper::append_string_view(field_value, dest);
-    }
-};
-
-// Full month name
-static const char *full_months[]{
-    "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
-class B_formatter : public flag_formatter
-{
-public:
-    explicit B_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        string_view_t field_value{full_months[tm_time.tm_mon]};
-        scoped_pad p(field_value, padinfo_, dest);
-        fmt_helper::append_string_view(field_value, dest);
-    }
-};
-
-// Date and time representation (Thu Aug 23 15:35:46 2014)
-class c_formatter final : public flag_formatter
-{
-public:
-    explicit c_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 24;
-        scoped_pad p(field_size, padinfo_, dest);
-
-        fmt_helper::append_string_view(days[tm_time.tm_wday], dest);
-        dest.push_back(' ');
-        fmt_helper::append_string_view(months[tm_time.tm_mon], dest);
-        dest.push_back(' ');
-        fmt_helper::append_int(tm_time.tm_mday, dest);
-        dest.push_back(' ');
-        // time
-
-        fmt_helper::pad2(tm_time.tm_hour, dest);
-        dest.push_back(':');
-        fmt_helper::pad2(tm_time.tm_min, dest);
-        dest.push_back(':');
-        fmt_helper::pad2(tm_time.tm_sec, dest);
-        dest.push_back(' ');
-        fmt_helper::append_int(tm_time.tm_year + 1900, dest);
-    }
-};
-
-// year - 2 digit
-class C_formatter final : public flag_formatter
-{
-public:
-    explicit C_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad2(tm_time.tm_year % 100, dest);
-    }
-};
-
-// Short MM/DD/YY date, equivalent to %m/%d/%y 08/23/01
-class D_formatter final : public flag_formatter
-{
-public:
-    explicit D_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 10;
-        scoped_pad p(field_size, padinfo_, dest);
-
-        fmt_helper::pad2(tm_time.tm_mon + 1, dest);
-        dest.push_back('/');
-        fmt_helper::pad2(tm_time.tm_mday, dest);
-        dest.push_back('/');
-        fmt_helper::pad2(tm_time.tm_year % 100, dest);
-    }
-};
-
-// year - 4 digit
-class Y_formatter final : public flag_formatter
-{
-public:
-    explicit Y_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 4;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::append_int(tm_time.tm_year + 1900, dest);
-    }
-};
-
-// month 1-12
-class m_formatter final : public flag_formatter
-{
-public:
-    explicit m_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad2(tm_time.tm_mon + 1, dest);
-    }
-};
-
-// day of month 1-31
-class d_formatter final : public flag_formatter
-{
-public:
-    explicit d_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad2(tm_time.tm_mday, dest);
-    }
-};
-
-// hours in 24 format 0-23
-class H_formatter final : public flag_formatter
-{
-public:
-    explicit H_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad2(tm_time.tm_hour, dest);
-    }
-};
-
-// hours in 12 format 1-12
-class I_formatter final : public flag_formatter
-{
-public:
-    explicit I_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad2(to12h(tm_time), dest);
-    }
-};
-
-// minutes 0-59
-class M_formatter final : public flag_formatter
-{
-public:
-    explicit M_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad2(tm_time.tm_min, dest);
-    }
-};
-
-// seconds 0-59
-class S_formatter final : public flag_formatter
-{
-public:
-    explicit S_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad2(tm_time.tm_sec, dest);
-    }
-};
-
-// milliseconds
-class e_formatter final : public flag_formatter
-{
-public:
-    explicit e_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        auto millis = fmt_helper::time_fraction<std::chrono::milliseconds>(msg.time);
-        if (padinfo_.enabled())
-        {
-            const size_t field_size = 3;
-            scoped_pad p(field_size, padinfo_, dest);
-            fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
-        }
-        else
-        {
-            fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
-        }
-    }
-};
-
-// microseconds
-class f_formatter final : public flag_formatter
-{
-public:
-    explicit f_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        auto micros = fmt_helper::time_fraction<std::chrono::microseconds>(msg.time);
-        if (padinfo_.enabled())
-        {
-            const size_t field_size = 6;
-            scoped_pad p(field_size, padinfo_, dest);
-            fmt_helper::pad6(static_cast<size_t>(micros.count()), dest);
-        }
-        else
-        {
-            fmt_helper::pad6(static_cast<size_t>(micros.count()), dest);
-        }
-    }
-};
-
-// nanoseconds
-class F_formatter final : public flag_formatter
-{
-public:
-    explicit F_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        auto ns = fmt_helper::time_fraction<std::chrono::nanoseconds>(msg.time);
-        if (padinfo_.enabled())
-        {
-            const size_t field_size = 9;
-            scoped_pad p(field_size, padinfo_, dest);
-            fmt_helper::pad9(static_cast<size_t>(ns.count()), dest);
-        }
-        else
-        {
-            fmt_helper::pad9(static_cast<size_t>(ns.count()), dest);
-        }
-    }
-};
-
-// seconds since epoch
-class E_formatter final : public flag_formatter
-{
-public:
-    explicit E_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 10;
-        scoped_pad p(field_size, padinfo_, dest);
-        auto duration = msg.time.time_since_epoch();
-        auto seconds = std::chrono::duration_cast<std::chrono::seconds>(duration).count();
-        fmt_helper::append_int(seconds, dest);
-    }
-};
-
-// AM/PM
-class p_formatter final : public flag_formatter
-{
-public:
-    explicit p_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 2;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::append_string_view(ampm(tm_time), dest);
-    }
-};
-
-// 12 hour clock 02:55:02 pm
-class r_formatter final : public flag_formatter
-{
-public:
-    explicit r_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 11;
-        scoped_pad p(field_size, padinfo_, dest);
-
-        fmt_helper::pad2(to12h(tm_time), dest);
-        dest.push_back(':');
-        fmt_helper::pad2(tm_time.tm_min, dest);
-        dest.push_back(':');
-        fmt_helper::pad2(tm_time.tm_sec, dest);
-        dest.push_back(' ');
-        fmt_helper::append_string_view(ampm(tm_time), dest);
-    }
-};
-
-// 24-hour HH:MM time, equivalent to %H:%M
-class R_formatter final : public flag_formatter
-{
-public:
-    explicit R_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 5;
-        scoped_pad p(field_size, padinfo_, dest);
-
-        fmt_helper::pad2(tm_time.tm_hour, dest);
-        dest.push_back(':');
-        fmt_helper::pad2(tm_time.tm_min, dest);
-    }
-};
-
-// ISO 8601 time format (HH:MM:SS), equivalent to %H:%M:%S
-class T_formatter final : public flag_formatter
-{
-public:
-    explicit T_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 8;
-        scoped_pad p(field_size, padinfo_, dest);
-
-        fmt_helper::pad2(tm_time.tm_hour, dest);
-        dest.push_back(':');
-        fmt_helper::pad2(tm_time.tm_min, dest);
-        dest.push_back(':');
-        fmt_helper::pad2(tm_time.tm_sec, dest);
-    }
-};
-
-// ISO 8601 offset from UTC in timezone (+-HH:MM)
-class z_formatter final : public flag_formatter
-{
-public:
-    explicit z_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    const std::chrono::seconds cache_refresh = std::chrono::seconds(5);
-
-    z_formatter() = default;
-    z_formatter(const z_formatter &) = delete;
-    z_formatter &operator=(const z_formatter &) = delete;
-
-    void format(const details::log_msg &msg, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 6;
-        scoped_pad p(field_size, padinfo_, dest);
-
-#ifdef _WIN32
-        int total_minutes = get_cached_offset(msg, tm_time);
-#else
-        // No need to chache under gcc,
-        // it is very fast (already stored in tm.tm_gmtoff)
-        (void)(msg);
-        int total_minutes = os::utc_minutes_offset(tm_time);
-#endif
-        bool is_negative = total_minutes < 0;
-        if (is_negative)
-        {
-            total_minutes = -total_minutes;
-            dest.push_back('-');
-        }
-        else
-        {
-            dest.push_back('+');
-        }
-
-        fmt_helper::pad2(total_minutes / 60, dest); // hours
-        dest.push_back(':');
-        fmt_helper::pad2(total_minutes % 60, dest); // minutes
-    }
-
-private:
-    log_clock::time_point last_update_{std::chrono::seconds(0)};
-#ifdef _WIN32
-    int offset_minutes_{0};
-
-    int get_cached_offset(const log_msg &msg, const std::tm &tm_time)
-    {
-        if (msg.time - last_update_ >= cache_refresh)
-        {
-            offset_minutes_ = os::utc_minutes_offset(tm_time);
-            last_update_ = msg.time;
-        }
-        return offset_minutes_;
-    }
-#endif
-};
-
-// Thread id
-class t_formatter final : public flag_formatter
-{
-public:
-    explicit t_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        if (padinfo_.enabled())
-        {
-            const auto field_size = fmt_helper::count_digits(msg.thread_id);
-            scoped_pad p(field_size, padinfo_, dest);
-            fmt_helper::append_int(msg.thread_id, dest);
-        }
-        else
-        {
-            fmt_helper::append_int(msg.thread_id, dest);
-        }
-    }
-};
-
-// Current pid
-class pid_formatter final : public flag_formatter
-{
-public:
-    explicit pid_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        const auto pid = static_cast<uint32_t>(details::os::pid());
-        if (padinfo_.enabled())
-        {
-            auto field_size = fmt_helper::count_digits(pid);
-            scoped_pad p(field_size, padinfo_, dest);
-            fmt_helper::append_int(pid, dest);
-        }
-        else
-        {
-            fmt_helper::append_int(pid, dest);
-        }
-    }
-};
-
-// message counter formatter
-class i_formatter final : public flag_formatter
-{
-public:
-    explicit i_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 6;
-        scoped_pad p(field_size, padinfo_, dest);
-        fmt_helper::pad6(msg.msg_id, dest);
-    }
-};
-
-class v_formatter final : public flag_formatter
-{
-public:
-    explicit v_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        if (padinfo_.enabled())
-        {
-            scoped_pad p(msg.payload, padinfo_, dest);
-            fmt_helper::append_string_view(msg.payload, dest);
-        }
-        else
-        {
-            fmt_helper::append_string_view(msg.payload, dest);
-        }
-    }
-};
-
-class ch_formatter final : public flag_formatter
-{
-public:
-    explicit ch_formatter(char ch)
-        : ch_(ch)
-    {
-    }
-
-    void format(const details::log_msg &, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        const size_t field_size = 1;
-        scoped_pad p(field_size, padinfo_, dest);
-        dest.push_back(ch_);
-    }
-
-private:
-    char ch_;
-};
-
-// aggregate user chars to display as is
-class aggregate_formatter final : public flag_formatter
-{
-public:
-    aggregate_formatter() = default;
-
-    void add_ch(char ch)
-    {
-        str_ += ch;
-    }
-    void format(const details::log_msg &, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        fmt_helper::append_string_view(str_, dest);
-    }
-
-private:
-    std::string str_;
-};
-
-// mark the color range. expect it to be in the form of "%^colored text%$"
-class color_start_formatter final : public flag_formatter
-{
-public:
-    explicit color_start_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        msg.color_range_start = dest.size();
-    }
-};
-class color_stop_formatter final : public flag_formatter
-{
-public:
-    explicit color_stop_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        msg.color_range_end = dest.size();
-    }
-};
-
-// print source location
-class source_location_formatter final : public flag_formatter
-{
-public:
-    explicit source_location_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        if (msg.source.empty())
-        {
-            return;
-        }
-        if (padinfo_.enabled())
-        {
-            const auto text_size = std::char_traits<char>::length(msg.source.filename) + fmt_helper::count_digits(msg.source.line) + 1;
-            scoped_pad p(text_size, padinfo_, dest);
-            fmt_helper::append_string_view(msg.source.filename, dest);
-            dest.push_back(':');
-            fmt_helper::append_int(msg.source.line, dest);
-        }
-        else
-        {
-            fmt_helper::append_string_view(msg.source.filename, dest);
-            dest.push_back(':');
-            fmt_helper::append_int(msg.source.line, dest);
-        }
-    }
-};
-// print source filename
-class source_filename_formatter final : public flag_formatter
-{
-public:
-    explicit source_filename_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        if (msg.source.empty())
-        {
-            return;
-        }
-        scoped_pad p(msg.source.filename, padinfo_, dest);
-        fmt_helper::append_string_view(msg.source.filename, dest);
-    }
-};
-
-class source_linenum_formatter final : public flag_formatter
-{
-public:
-    explicit source_linenum_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        if (msg.source.empty())
-        {
-            return;
-        }
-        if (padinfo_.enabled())
-        {
-            auto field_size = fmt_helper::count_digits(msg.source.line);
-            scoped_pad p(field_size, padinfo_, dest);
-            fmt_helper::append_int(msg.source.line, dest);
-        }
-        else
-        {
-            fmt_helper::append_int(msg.source.line, dest);
-        }
-    }
-};
-// print source funcname
-class source_funcname_formatter final : public flag_formatter
-{
-public:
-    explicit source_funcname_formatter(padding_info padinfo)
-        : flag_formatter(padinfo){};
-
-    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
-    {
-        if (msg.source.empty())
-        {
-            return;
-        }
-        scoped_pad p(msg.source.funcname, padinfo_, dest);
-        fmt_helper::append_string_view(msg.source.funcname, dest);
-    }
-};
-
-// Full info formatter
-// pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] %v
-class full_formatter final : public flag_formatter
-{
-public:
-    explicit full_formatter(padding_info padinfo)
-        : flag_formatter(padinfo)
-    {
-    }
-
-    void format(const details::log_msg &msg, const std::tm &tm_time, fmt::memory_buffer &dest) override
-    {
-        using std::chrono::duration_cast;
-        using std::chrono::milliseconds;
-        using std::chrono::seconds;
-
-#ifndef SPDLOG_NO_DATETIME
-
-        // cache the date/time part for the next second.
-        auto duration = msg.time.time_since_epoch();
-        auto secs = duration_cast<seconds>(duration);
-
-        if (cache_timestamp_ != secs || cached_datetime_.size() == 0)
-        {
-            cached_datetime_.clear();
-            cached_datetime_.push_back('[');
-            fmt_helper::append_int(tm_time.tm_year + 1900, cached_datetime_);
-            cached_datetime_.push_back('-');
-
-            fmt_helper::pad2(tm_time.tm_mon + 1, cached_datetime_);
-            cached_datetime_.push_back('-');
-
-            fmt_helper::pad2(tm_time.tm_mday, cached_datetime_);
-            cached_datetime_.push_back(' ');
-
-            fmt_helper::pad2(tm_time.tm_hour, cached_datetime_);
-            cached_datetime_.push_back(':');
-
-            fmt_helper::pad2(tm_time.tm_min, cached_datetime_);
-            cached_datetime_.push_back(':');
-
-            fmt_helper::pad2(tm_time.tm_sec, cached_datetime_);
-            cached_datetime_.push_back('.');
-
-            cache_timestamp_ = secs;
-        }
-        fmt_helper::append_buf(cached_datetime_, dest);
-
-        auto millis = fmt_helper::time_fraction<milliseconds>(msg.time);
-        fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
-        dest.push_back(']');
-        dest.push_back(' ');
-
-#else // no datetime needed
-        (void)tm_time;
-#endif
-
-#ifndef SPDLOG_NO_NAME
-        if (!msg.logger_name->empty())
-        {
-            dest.push_back('[');
-            // fmt_helper::append_str(*msg.logger_name, dest);
-            fmt_helper::append_string_view(*msg.logger_name, dest);
-            dest.push_back(']');
-            dest.push_back(' ');
-        }
-#endif
-
-        dest.push_back('[');
-        // wrap the level name with color
-        msg.color_range_start = dest.size();
-        // fmt_helper::append_string_view(level::to_c_str(msg.level), dest);
-        fmt_helper::append_string_view(level::to_string_view(msg.level), dest);
-        msg.color_range_end = dest.size();
-        dest.push_back(']');
-        dest.push_back(' ');
-
-        // add source location if present
-        if (!msg.source.empty())
-        {
-            dest.push_back('[');
-            fmt_helper::append_string_view(msg.source.filename, dest);
-            dest.push_back(':');
-            fmt_helper::append_int(msg.source.line, dest);
-            dest.push_back(']');
-            dest.push_back(' ');
-        }
-        // fmt_helper::append_string_view(msg.msg(), dest);
-        fmt_helper::append_string_view(msg.payload, dest);
-    }
-
-private:
-    std::chrono::seconds cache_timestamp_{0};
-    fmt::basic_memory_buffer<char, 128> cached_datetime_;
-};
-
-} // namespace details
-
 class pattern_formatter final : public formatter
 {
 public:
     explicit pattern_formatter(
-        std::string pattern, pattern_time_type time_type = pattern_time_type::local, std::string eol = spdlog::details::os::default_eol)
-        : pattern_(std::move(pattern))
-        , eol_(std::move(eol))
-        , pattern_time_type_(time_type)
-        , last_log_secs_(0)
-    {
-        std::memset(&cached_tm_, 0, sizeof(cached_tm_));
-        compile_pattern_(pattern_);
-    }
-
-    // use by default full formatter for if pattern is not given
-    explicit pattern_formatter(pattern_time_type time_type = pattern_time_type::local, std::string eol = spdlog::details::os::default_eol)
-        : pattern_("%+")
-        , eol_(std::move(eol))
-        , pattern_time_type_(time_type)
-        , last_log_secs_(0)
-    {
-        std::memset(&cached_tm_, 0, sizeof(cached_tm_));
-        formatters_.push_back(details::make_unique<details::full_formatter>(details::padding_info{}));
-    }
+        std::string pattern, 
+		pattern_time_type time_type = pattern_time_type::local, 
+		std::string eol = spdlog::details::os::default_eol);
+        
+    // use default pattern is not given
+    explicit pattern_formatter(
+		pattern_time_type time_type = pattern_time_type::local,
+		std::string eol = spdlog::details::os::default_eol);        
 
     pattern_formatter(const pattern_formatter &other) = delete;
     pattern_formatter &operator=(const pattern_formatter &other) = delete;
 
-    std::unique_ptr<formatter> clone() const override
-    {
-        return details::make_unique<pattern_formatter>(pattern_, pattern_time_type_, eol_);
-    }
-
-    void format(const details::log_msg &msg, fmt::memory_buffer &dest) override
-    {
-#ifndef SPDLOG_NO_DATETIME
-        auto secs = std::chrono::duration_cast<std::chrono::seconds>(msg.time.time_since_epoch());
-        if (secs != last_log_secs_)
-        {
-            cached_tm_ = get_time_(msg);
-            last_log_secs_ = secs;
-        }
-#endif
-        for (auto &f : formatters_)
-        {
-            f->format(msg, cached_tm_, dest);
-        }
-        // write eol
-        details::fmt_helper::append_string_view(eol_, dest);
-    }
+    std::unique_ptr<formatter> clone() const override;
+    void format(const details::log_msg &msg, fmt::memory_buffer &dest) override;    
 
 private:
     std::string pattern_;
@@ -1067,273 +88,20 @@ private:
     pattern_time_type pattern_time_type_;
     std::tm cached_tm_;
     std::chrono::seconds last_log_secs_;
-
     std::vector<std::unique_ptr<details::flag_formatter>> formatters_;
+    std::tm get_time_(const details::log_msg &msg);   
 
-    std::tm get_time_(const details::log_msg &msg)
-    {
-        if (pattern_time_type_ == pattern_time_type::local)
-        {
-            return details::os::localtime(log_clock::to_time_t(msg.time));
-        }
-        return details::os::gmtime(log_clock::to_time_t(msg.time));
-    }
-
-    void handle_flag_(char flag, details::padding_info padding)
-    {
-        switch (flag)
-        {
-
-        case ('+'): // default formatter
-            formatters_.push_back(details::make_unique<details::full_formatter>(padding));
-            break;
-
-        case 'n': // logger name
-            formatters_.push_back(details::make_unique<details::name_formatter>(padding));
-            break;
-
-        case 'l': // level
-            formatters_.push_back(details::make_unique<details::level_formatter>(padding));
-            break;
-
-        case 'L': // short level
-            formatters_.push_back(details::make_unique<details::short_level_formatter>(padding));
-            break;
-
-        case ('t'): // thread id
-            formatters_.push_back(details::make_unique<details::t_formatter>(padding));
-            break;
-
-        case ('v'): // the message text
-            formatters_.push_back(details::make_unique<details::v_formatter>(padding));
-            break;
-
-        case ('a'): // weekday
-            formatters_.push_back(details::make_unique<details::a_formatter>(padding));
-            break;
-
-        case ('A'): // short weekday
-            formatters_.push_back(details::make_unique<details::A_formatter>(padding));
-            break;
-
-        case ('b'):
-        case ('h'): // month
-            formatters_.push_back(details::make_unique<details::b_formatter>(padding));
-            break;
-
-        case ('B'): // short month
-            formatters_.push_back(details::make_unique<details::B_formatter>(padding));
-            break;
-
-        case ('c'): // datetime
-            formatters_.push_back(details::make_unique<details::c_formatter>(padding));
-            break;
-
-        case ('C'): // year 2 digits
-            formatters_.push_back(details::make_unique<details::C_formatter>(padding));
-            break;
-
-        case ('Y'): // year 4 digits
-            formatters_.push_back(details::make_unique<details::Y_formatter>(padding));
-            break;
-
-        case ('D'):
-        case ('x'): // datetime MM/DD/YY
-            formatters_.push_back(details::make_unique<details::D_formatter>(padding));
-            break;
-
-        case ('m'): // month 1-12
-            formatters_.push_back(details::make_unique<details::m_formatter>(padding));
-            break;
-
-        case ('d'): // day of month 1-31
-            formatters_.push_back(details::make_unique<details::d_formatter>(padding));
-            break;
-
-        case ('H'): // hours 24
-            formatters_.push_back(details::make_unique<details::H_formatter>(padding));
-            break;
-
-        case ('I'): // hours 12
-            formatters_.push_back(details::make_unique<details::I_formatter>(padding));
-            break;
-
-        case ('M'): // minutes
-            formatters_.push_back(details::make_unique<details::M_formatter>(padding));
-            break;
-
-        case ('S'): // seconds
-            formatters_.push_back(details::make_unique<details::S_formatter>(padding));
-            break;
-
-        case ('e'): // milliseconds
-            formatters_.push_back(details::make_unique<details::e_formatter>(padding));
-            break;
-
-        case ('f'): // microseconds
-            formatters_.push_back(details::make_unique<details::f_formatter>(padding));
-            break;
-
-        case ('F'): // nanoseconds
-            formatters_.push_back(details::make_unique<details::F_formatter>(padding));
-            break;
-
-        case ('E'): // seconds since epoch
-            formatters_.push_back(details::make_unique<details::E_formatter>(padding));
-            break;
-
-        case ('p'): // am/pm
-            formatters_.push_back(details::make_unique<details::p_formatter>(padding));
-            break;
-
-        case ('r'): // 12 hour clock 02:55:02 pm
-            formatters_.push_back(details::make_unique<details::r_formatter>(padding));
-            break;
-
-        case ('R'): // 24-hour HH:MM time
-            formatters_.push_back(details::make_unique<details::R_formatter>(padding));
-            break;
-
-        case ('T'):
-        case ('X'): // ISO 8601 time format (HH:MM:SS)
-            formatters_.push_back(details::make_unique<details::T_formatter>(padding));
-            break;
-
-        case ('z'): // timezone
-            formatters_.push_back(details::make_unique<details::z_formatter>(padding));
-            break;
-
-        case ('P'): // pid
-            formatters_.push_back(details::make_unique<details::pid_formatter>(padding));
-            break;
-
-#ifdef SPDLOG_ENABLE_MESSAGE_COUNTER
-        case ('i'):
-            formatters_.push_back(details::make_unique<details::i_formatter>(padding));
-            break;
-#endif
-        case ('^'): // color range start
-            formatters_.push_back(details::make_unique<details::color_start_formatter>(padding));
-            break;
-
-        case ('$'): // color range end
-            formatters_.push_back(details::make_unique<details::color_stop_formatter>(padding));
-            break;
-
-        case ('@'): // source location (filename:filenumber)
-            formatters_.push_back(details::make_unique<details::source_location_formatter>(padding));
-            break;
-
-        case ('s'): // source filename
-            formatters_.push_back(details::make_unique<details::source_filename_formatter>(padding));
-            break;
-
-        case ('#'): // source line number
-            formatters_.push_back(details::make_unique<details::source_linenum_formatter>(padding));
-            break;
-
-        case ('!'): // source funcname
-            formatters_.push_back(details::make_unique<details::source_funcname_formatter>(padding));
-            break;
-
-        case ('%'): // % char
-            formatters_.push_back(details::make_unique<details::ch_formatter>('%'));
-            break;
-
-        default: // Unknown flag appears as is
-            auto unknown_flag = details::make_unique<details::aggregate_formatter>();
-            unknown_flag->add_ch('%');
-            unknown_flag->add_ch(flag);
-            formatters_.push_back((std::move(unknown_flag)));
-            break;
-        }
-    }
-
+    void handle_flag_(char flag, details::padding_info padding);
+   
     // Extract given pad spec (e.g. %8X)
     // Advance the given it pass the end of the padding spec found (if any)
     // Return padding.
-    details::padding_info handle_padspec_(std::string::const_iterator &it, std::string::const_iterator end)
-    {
-        using details::padding_info;
-        using details::scoped_pad;
-        const size_t max_width = 128;
-        if (it == end)
-        {
-            return padding_info{};
-        }
-
-        padding_info::pad_side side;
-        switch (*it)
-        {
-        case '-':
-            side = padding_info::right;
-            ++it;
-            break;
-        case '=':
-            side = padding_info::center;
-            ++it;
-            break;
-        default:
-            side = details::padding_info::left;
-            break;
-        }
-
-        if (it == end || !std::isdigit(static_cast<unsigned char>(*it)))
-        {
-            return padding_info{0, side};
-        }
-
-        auto width = static_cast<size_t>(*it - '0');
-        for (++it; it != end && std::isdigit(static_cast<unsigned char>(*it)); ++it)
-        {
-            auto digit = static_cast<size_t>(*it - '0');
-            width = width * 10 + digit;
-        }
-        return details::padding_info{std::min<size_t>(width, max_width), side};
-    }
-
-    void compile_pattern_(const std::string &pattern)
-    {
-        auto end = pattern.end();
-        std::unique_ptr<details::aggregate_formatter> user_chars;
-        formatters_.clear();
-        for (auto it = pattern.begin(); it != end; ++it)
-        {
-            if (*it == '%')
-            {
-                if (user_chars) // append user chars found so far
-                {
-                    formatters_.push_back(std::move(user_chars));
-                }
-
-                auto padding = handle_padspec_(++it, end);
-
-                if (it != end)
-                {
-                    handle_flag_(*it, padding);
-                }
-                else
-                {
-                    break;
-                }
-            }
-            else // chars not following the % sign should be displayed as is
-            {
-                if (!user_chars)
-                {
-                    user_chars = details::make_unique<details::aggregate_formatter>();
-                }
-                user_chars->add_ch(*it);
-            }
-        }
-        if (user_chars) // append raw chars found so far
-        {
-            formatters_.push_back(std::move(user_chars));
-        }
-    }
+    details::padding_info handle_padspec_(std::string::const_iterator &it, std::string::const_iterator end);
+    
+    void compile_pattern_(const std::string &pattern);
 };
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
-#include "../src/os.cpp"
+#include "../src/pattern_formatter.cpp"
 #endif
diff --git a/include/spdlog/details/registry.h b/include/spdlog/details/registry.h
index ab4cf3f8..252f44df 100644
--- a/include/spdlog/details/registry.h
+++ b/include/spdlog/details/registry.h
@@ -154,7 +154,7 @@ public:
         periodic_flusher_ = details::make_unique<periodic_worker>(clbk, interval);
     }
 
-    void set_error_handler(log_err_handler handler)
+    void set_error_handler(void (*handler)(const std::string &msg))
     {
         std::lock_guard<std::mutex> lock(logger_map_mutex_);
         for (auto &l : loggers_)
@@ -275,7 +275,7 @@ private:
     std::unique_ptr<formatter> formatter_;
     level::level_enum level_ = spdlog::logger::default_level();
     level::level_enum flush_level_ = level::off;
-    log_err_handler err_handler_;
+    void (*err_handler_)(const std::string &msg);
     std::shared_ptr<thread_pool> tp_;
     std::unique_ptr<periodic_worker> periodic_flusher_;
     std::shared_ptr<logger> default_logger_;
diff --git a/include/spdlog/logger.h b/include/spdlog/logger.h
index f178281d..210f9af2 100644
--- a/include/spdlog/logger.h
+++ b/include/spdlog/logger.h
@@ -17,26 +17,21 @@
 // The use of private formatter per sink provides the opportunity to cache some
 // formatted data, and support for different format per sink.
 
-
 #include "spdlog/common.h"
 #include "spdlog/details/log_msg.h"
 
-//#include "spdlog/formatter.h"
-//#include "spdlog/sinks/sink.h"
-
 #include <memory>
 #include <string>
 #include <vector>
 
-namespace spdlog
+namespace spdlog {
+class logger
 {
-    class logger
-    {
-    public:
+public:
         template<typename It>
         logger(std::string name, It begin, It end)
             : name_(std::move(name))
-            , sinks_(begin, end)
+            , sinks_(begin, end)  			
         {
         }
 
@@ -57,32 +52,32 @@ namespace spdlog
         template<typename... Args>
         void log(source_loc loc, level::level_enum lvl, const char *fmt, const Args &... args)
         {
-            if (!should_log(lvl))
-            {
-                return;
-            }
+        if (!should_log(lvl))
+        {
+            return;
+        }
 
-            try
-            {                
-                fmt::memory_buffer buf;
-                fmt::format_to(buf, fmt, args...);
-                details::log_msg log_msg(loc, &name_, lvl, string_view_t(buf.data(), buf.size()));
-                sink_it_(log_msg);
-            }
-            catch (const std::exception &ex)
-            {
-                err_handler_(ex.what());
-            }
-            catch (...)
-            {
-                err_handler_("Unknown exception in logger");
-            }
+        try
+        {
+            fmt::memory_buffer buf;
+            fmt::format_to(buf, fmt, args...);
+            details::log_msg log_msg(loc, &name_, lvl, string_view_t(buf.data(), buf.size()));
+            sink_it_(log_msg);
+        }
+        catch (const std::exception &ex)
+        {
+            err_handler_(ex.what());
+        }
+        catch (...)
+        {
+            err_handler_("Unknown exception in logger");
+        }
         }
 
         template<typename... Args>
         void log(level::level_enum lvl, const char *fmt, const Args &... args)
         {
-            log(source_loc{}, lvl, fmt, args...);
+        log(source_loc{}, lvl, fmt, args...);
         }
         void log(source_loc loc, level::level_enum lvl, const char *msg);
         void log(level::level_enum lvl, const char *msg);
@@ -90,37 +85,37 @@ namespace spdlog
         template<typename... Args>
         void trace(const char *fmt, const Args &... args)
         {
-            log(level::trace, fmt, args...);
+        log(level::trace, fmt, args...);
         }
 
         template<typename... Args>
         void debug(const char *fmt, const Args &... args)
         {
-            log(level::debug, fmt, args...);
+        log(level::debug, fmt, args...);
         }
 
         template<typename... Args>
         void info(const char *fmt, const Args &... args)
         {
-            log(level::info, fmt, args...);
+        log(level::info, fmt, args...);
         }
 
         template<typename... Args>
         void warn(const char *fmt, const Args &... args)
         {
-            log(level::warn, fmt, args...);
+        log(level::warn, fmt, args...);
         }
 
         template<typename... Args>
         void error(const char *fmt, const Args &... args)
         {
-            log(level::err, fmt, args...);
+        log(level::err, fmt, args...);
         }
 
         template<typename... Args>
         void critical(const char *fmt, const Args &... args)
         {
-            log(level::critical, fmt, args...);
+        log(level::critical, fmt, args...);
         }
 
 #ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
@@ -129,87 +124,87 @@ namespace spdlog
 #else
         inline void wbuf_to_utf8buf(const fmt::wmemory_buffer &wbuf, fmt::memory_buffer &target)
         {
-            int wbuf_size = static_cast<int>(wbuf.size());
-            if (wbuf_size == 0)
-            {
-                return;
-            }
+        int wbuf_size = static_cast<int>(wbuf.size());
+        if (wbuf_size == 0)
+        {
+            return;
+        }
 
-            auto result_size = ::WideCharToMultiByte(CP_UTF8, 0, wbuf.data(), wbuf_size, NULL, 0, NULL, NULL);
+        auto result_size = ::WideCharToMultiByte(CP_UTF8, 0, wbuf.data(), wbuf_size, NULL, 0, NULL, NULL);
 
-            if (result_size > 0)
-            {
-                target.resize(result_size);
-                ::WideCharToMultiByte(CP_UTF8, 0, wbuf.data(), wbuf_size, &target.data()[0], result_size, NULL, NULL);
-            }
-            else
-            {
-                throw spdlog::spdlog_ex(fmt::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
-            }
+        if (result_size > 0)
+        {
+            target.resize(result_size);
+            ::WideCharToMultiByte(CP_UTF8, 0, wbuf.data(), wbuf_size, &target.data()[0], result_size, NULL, NULL);
+        }
+        else
+        {
+            throw spdlog::spdlog_ex(fmt::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
+        }
         }
 
         template<typename... Args>
         void log(source_loc source, level::level_enum lvl, const wchar_t *fmt, const Args &... args)
         {
-            if (!should_log(lvl))
-            {
-                return;
-            }
+        if (!should_log(lvl))
+        {
+            return;
+        }
 
-            try
-            {
-                // format to wmemory_buffer and convert to utf8
-                using details::fmt_helper::to_string_view;
-                fmt::wmemory_buffer wbuf;
-                fmt::format_to(wbuf, fmt, args...);
-                fmt::memory_buffer buf;
-                wbuf_to_utf8buf(wbuf, buf);
-                details::log_msg log_msg(source, &name_, lvl, to_string_view(buf));
-                sink_it_(log_msg);
-            }
-            SPDLOG_CATCH_AND_HANDLE
+        try
+        {
+            // format to wmemory_buffer and convert to utf8
+            using details::fmt_helper::to_string_view;
+            fmt::wmemory_buffer wbuf;
+            fmt::format_to(wbuf, fmt, args...);
+            fmt::memory_buffer buf;
+            wbuf_to_utf8buf(wbuf, buf);
+            details::log_msg log_msg(source, &name_, lvl, to_string_view(buf));
+            sink_it_(log_msg);
+        }
+        SPDLOG_CATCH_AND_HANDLE
         }
 
         template<typename... Args>
         void log(level::level_enum lvl, const wchar_t *fmt, const Args &... args)
         {
-            log(source_loc{}, lvl, fmt, args...);
+        log(source_loc{}, lvl, fmt, args...);
         }
 
         template<typename... Args>
         void trace(const wchar_t *fmt, const Args &... args)
         {
-            log(level::trace, fmt, args...);
+        log(level::trace, fmt, args...);
         }
 
         template<typename... Args>
         void debug(const wchar_t *fmt, const Args &... args)
         {
-            log(level::debug, fmt, args...);
+        log(level::debug, fmt, args...);
         }
 
         template<typename... Args>
         void info(const wchar_t *fmt, const Args &... args)
         {
-            log(level::info, fmt, args...);
+        log(level::info, fmt, args...);
         }
 
         template<typename... Args>
         void warn(const wchar_t *fmt, const Args &... args)
         {
-            log(level::warn, fmt, args...);
+        log(level::warn, fmt, args...);
         }
 
         template<typename... Args>
         void error(const wchar_t *fmt, const Args &... args)
         {
-            log(level::err, fmt, args...);
+        log(level::err, fmt, args...);
         }
 
         template<typename... Args>
         void critical(const wchar_t *fmt, const Args &... args)
         {
-            log(level::critical, fmt, args...);
+        log(level::critical, fmt, args...);
         }
 #endif // _WIN32
 #endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
@@ -217,92 +212,92 @@ namespace spdlog
         template<typename T>
         void log(level::level_enum lvl, const T &msg)
         {
-            log(source_loc{}, lvl, msg);
+        log(source_loc{}, lvl, msg);
         }
 
         // T can be statically converted to string_view
         template<class T, typename std::enable_if<std::is_convertible<T, spdlog::string_view_t>::value, T>::type * = nullptr>
         void log(source_loc loc, level::level_enum lvl, const T &msg)
         {
-            if (!should_log(lvl))
-            {
-                return;
-            }
-            try
-            {
-                details::log_msg log_msg(loc, &name_, lvl, msg);
-                sink_it_(log_msg);
-            }
-            catch (const std::exception &ex)
-            {
-                err_handler_(ex.what());
-            }
-            catch (...)
-            {
-                err_handler_("Unknown exception in logger");
-            }
+        if (!should_log(lvl))
+        {
+            return;
+        }
+        try
+        {
+            details::log_msg log_msg(loc, &name_, lvl, msg);
+            sink_it_(log_msg);
+        }
+        catch (const std::exception &ex)
+        {
+            err_handler_(ex.what());
+        }
+        catch (...)
+        {
+            err_handler_("Unknown exception in logger");
+        }
         }
 
         // T cannot be statically converted to string_view
         template<class T, typename std::enable_if<!std::is_convertible<T, spdlog::string_view_t>::value, T>::type * = nullptr>
         void log(source_loc loc, level::level_enum lvl, const T &msg)
         {
-            if (!should_log(lvl))
-            {
-                return;
-            }
-            try
-            {
-                using details::fmt_helper::to_string_view;
-                fmt::memory_buffer buf;
-                fmt::format_to(buf, "{}", msg);
-                details::log_msg log_msg(loc, &name_, lvl, to_string_view(buf));
-                sink_it_(log_msg);
-            }
-            catch (const std::exception &ex)
-            {
-                err_handler_(ex.what());
-            }
-            catch (...)
-            {
-                err_handler_("Unknown exception in logger");
-            }
+        if (!should_log(lvl))
+        {
+            return;
+        }
+        try
+        {
+            using details::fmt_helper::to_string_view;
+            fmt::memory_buffer buf;
+            fmt::format_to(buf, "{}", msg);
+            details::log_msg log_msg(loc, &name_, lvl, to_string_view(buf));
+            sink_it_(log_msg);
+        }
+        catch (const std::exception &ex)
+        {
+            err_handler_(ex.what());
+        }
+        catch (...)
+        {
+            err_handler_("Unknown exception in logger");
+        }
         }
 
         template<typename T>
         void trace(const T &msg)
         {
-            log(level::trace, msg);
+        log(level::trace, msg);
         }
 
         template<typename T>
         void debug(const T &msg)
         {
-            log(level::debug, msg);
+        log(level::debug, msg);
         }
 
         template<typename T>
         void info(const T &msg)
         {
-            log(level::info, msg);
+        log(level::info, msg);
         }
 
         template<typename T>
         void warn(const T &msg)
         {
-            log(level::warn, msg);
+        log(level::warn, msg);
         }
 
         template<typename T>
         void error(const T &msg)
         {
-            log(level::err, msg);
+        log(level::err, msg);
         }
 
         template<typename T>
         void critical(const T &msg)
         {
-            log(level::critical, msg);
+        log(level::critical, msg);
         }
 
         bool should_log(level::level_enum msg_level) const;
@@ -332,10 +327,8 @@ namespace spdlog
         std::vector<sink_ptr> &sinks();
 
         // error handler
-        void set_error_handler(log_err_handler err_handler);
-
-        log_err_handler error_handler() const;
-
+        void set_error_handler(void (*handler)(const std::string& msg));
+        
         // create new logger with same sinks and configuration.
         virtual std::shared_ptr<logger> clone(std::string logger_name);
 
@@ -347,7 +340,7 @@ namespace spdlog
 
         // default error handler.
         // print the error to stderr with the max rate of 1 message/minute.
-        void default_err_handler_(const std::string &msg);
+        void err_handler_(const std::string &msg);
 
         // increment the message count (only if defined(SPDLOG_ENABLE_MESSAGE_COUNTER))
         void incr_msg_counter_(details::log_msg &msg);
@@ -356,10 +349,8 @@ namespace spdlog
         std::vector<sink_ptr> sinks_;
         spdlog::level_t level_{spdlog::logger::default_level()};
         spdlog::level_t flush_level_{level::off};
-        log_err_handler err_handler_{[this](const std::string &msg) { this->default_err_handler_(msg); }};
-        std::atomic<time_t> last_err_time_{0};
-        std::atomic<size_t> msg_counter_{1};
-    };
+        void (*custom_err_handler_)(const std::string &msg) {nullptr};                        
+};
 } // namespace spdlog
 
 #ifdef SPDLOG_HEADER_ONLY
diff --git a/include/spdlog/spdlog.h b/include/spdlog/spdlog.h
index fd9a1d27..a70a7aa7 100644
--- a/include/spdlog/spdlog.h
+++ b/include/spdlog/spdlog.h
@@ -103,9 +103,9 @@ inline void flush_every(std::chrono::seconds interval)
 }
 
 // Set global error handler
-inline void set_error_handler(log_err_handler handler)
+inline void set_error_handler(void (*handler)(const std::string &msg))
 {
-    details::registry::instance().set_error_handler(std::move(handler));
+    details::registry::instance().set_error_handler(handler);
 }
 
 // Register the given logger with the given name
diff --git a/include/spdlog/tweakme.h b/include/spdlog/tweakme.h
index dfcb09d2..beae4f74 100644
--- a/include/spdlog/tweakme.h
+++ b/include/spdlog/tweakme.h
@@ -107,13 +107,6 @@
 // #define SPDLOG_PREVENT_CHILD_FD
 ///////////////////////////////////////////////////////////////////////////////
 
-///////////////////////////////////////////////////////////////////////////////
-// Uncomment to enable message counting feature.
-// Use the %i in the logger pattern to display log message sequence id.
-//
-// #define SPDLOG_ENABLE_MESSAGE_COUNTER
-///////////////////////////////////////////////////////////////////////////////
-
 ///////////////////////////////////////////////////////////////////////////////
 // Uncomment to customize level names (e.g. "MT TRACE")
 //
diff --git a/src/logger.cpp b/src/logger.cpp
index 88ff4d3b..cc28d883 100644
--- a/src/logger.cpp
+++ b/src/logger.cpp
@@ -113,14 +113,9 @@ SPDLOG_INLINE std::vector<spdlog::sink_ptr> &spdlog::logger::sinks()
 }
 
 // error handler
-SPDLOG_INLINE void spdlog::logger::set_error_handler(spdlog::log_err_handler err_handler)
+SPDLOG_INLINE void spdlog::logger::set_error_handler(void (*handler)(const std::string &msg))
 {
-    err_handler_ = std::move(err_handler);
-}
-
-SPDLOG_INLINE spdlog::log_err_handler spdlog::logger::error_handler() const
-{
-    return err_handler_;
+    custom_err_handler_ = handler;
 }
 
 // create new logger with same sinks and configuration.
@@ -129,16 +124,13 @@ SPDLOG_INLINE std::shared_ptr<spdlog::logger> spdlog::logger::clone(std::string
     auto cloned = std::make_shared<spdlog::logger>(std::move(logger_name), sinks_.begin(), sinks_.end());
     cloned->set_level(this->level());
     cloned->flush_on(this->flush_level());
-    cloned->set_error_handler(this->error_handler());
+    cloned->set_error_handler(this->custom_err_handler_);
     return cloned;
 }
 
 // protected methods
 SPDLOG_INLINE void spdlog::logger::sink_it_(spdlog::details::log_msg &msg)
 {
-#if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
-    incr_msg_counter_(msg);
-#endif
     for (auto &sink : sinks_)
     {
         if (sink->should_log(msg.level))
@@ -167,21 +159,17 @@ SPDLOG_INLINE bool spdlog::logger::should_flush_(const spdlog::details::log_msg
     return (msg.level >= flush_level) && (msg.level != level::off);
 }
 
-SPDLOG_INLINE void spdlog::logger::default_err_handler_(const std::string &msg)
-{
-    auto now = time(nullptr);
-    if (now - last_err_time_ < 60)
+void spdlog::logger::err_handler_(const std::string &msg)
+{    
+	if (custom_err_handler_)
+	{
+		custom_err_handler_(msg);
+	}
+    else
     {
-        return;
+        auto tm_time = spdlog::details::os::localtime();
+        char date_buf[64];
+        std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
+        fmt::print(stderr, "[*** LOG ERROR ***] [{}] [{}] {}\n", date_buf, name(), msg);
     }
-    last_err_time_ = now;
-    auto tm_time = details::os::localtime(now);
-    char date_buf[100];
-    std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
-    fmt::print(stderr, "[*** LOG ERROR ***] [{}] [{}] {}\n", date_buf, name(), msg);
-}
-
-SPDLOG_INLINE void spdlog::logger::incr_msg_counter_(spdlog::details::log_msg &msg)
-{
-    msg.msg_id = msg_counter_.fetch_add(1, std::memory_order_relaxed);
-}
+}
\ No newline at end of file
diff --git a/src/os.cpp b/src/os.cpp
index 4a8248f0..9df80e3b 100644
--- a/src/os.cpp
+++ b/src/os.cpp
@@ -344,14 +344,12 @@ SPDLOG_INLINE void sleep_for_millis(int milliseconds) SPDLOG_NOEXCEPT
 
 // wchar support for windows file names (SPDLOG_WCHAR_FILENAMES must be defined)
 #if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
-#define SPDLOG_FILENAME_T(s) L##s
 SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
 {
     std::wstring_convert<std::codecvt_utf8<wchar_t>, wchar_t> c;
     return c.to_bytes(filename);
 }
 #else
-#define SPDLOG_FILENAME_T(s) s
 SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
 {
     return filename;
diff --git a/src/pattern_formatter.cpp b/src/pattern_formatter.cpp
new file mode 100644
index 00000000..b3037480
--- /dev/null
+++ b/src/pattern_formatter.cpp
@@ -0,0 +1,1266 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#ifndef SPDLOG_HEADER_ONLY
+#include "spdlog/details/pattern_formatter.h"
+#endif // !SPDLOG_HEADER_ONLY
+
+#include "spdlog/details/fmt_helper.h"
+#include "spdlog/details/log_msg.h"
+#include "spdlog/details/os.h"
+#include "spdlog/fmt/fmt.h"
+#include "spdlog/formatter.h"
+
+#include <array>
+#include <chrono>
+#include <ctime>
+#include <cctype>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <thread>
+#include <utility>
+#include <vector>
+
+namespace spdlog {
+namespace details {
+
+///////////////////////////////////////////////////////////////////////
+// name & level pattern appender
+///////////////////////////////////////////////////////////////////////
+
+class scoped_pad
+{
+public:
+    scoped_pad(size_t wrapped_size, padding_info &padinfo, fmt::memory_buffer &dest)
+        : padinfo_(padinfo)
+        , dest_(dest)
+    {
+
+        if (padinfo_.width_ <= wrapped_size)
+        {
+            total_pad_ = 0;
+            return;
+        }
+
+        total_pad_ = padinfo.width_ - wrapped_size;
+        if (padinfo_.side_ == padding_info::left)
+        {
+            pad_it(total_pad_);
+            total_pad_ = 0;
+        }
+        else if (padinfo_.side_ == padding_info::center)
+        {
+            auto half_pad = total_pad_ / 2;
+            auto reminder = total_pad_ & 1;
+            pad_it(half_pad);
+            total_pad_ = half_pad + reminder; // for the right side
+        }
+    }
+
+    scoped_pad(spdlog::string_view_t txt, padding_info &padinfo, fmt::memory_buffer &dest)
+        : scoped_pad(txt.size(), padinfo, dest)
+    {
+    }
+
+    ~scoped_pad()
+    {
+        if (total_pad_)
+        {
+            pad_it(total_pad_);
+        }
+    }
+
+private:
+    void pad_it(size_t count)
+    {
+        // count = std::min(count, spaces_.size());
+        assert(count <= spaces_.size());
+        fmt_helper::append_string_view(string_view_t(spaces_.data(), count), dest_);
+    }
+
+    const padding_info &padinfo_;
+    fmt::memory_buffer &dest_;
+    size_t total_pad_;
+    string_view_t spaces_{"                                                                "
+                          "                                                                ",
+        128};
+};
+
+class name_formatter : public flag_formatter
+{
+public:
+    explicit name_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        if (padinfo_.enabled())
+        {
+            scoped_pad p(*msg.logger_name, padinfo_, dest);
+            fmt_helper::append_string_view(*msg.logger_name, dest);
+        }
+        else
+        {
+            fmt_helper::append_string_view(*msg.logger_name, dest);
+        }
+    }
+};
+
+// log level appender
+class level_formatter : public flag_formatter
+{
+public:
+    explicit level_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        string_view_t &level_name = level::to_string_view(msg.level);
+        if (padinfo_.enabled())
+        {
+            scoped_pad p(level_name, padinfo_, dest);
+            fmt_helper::append_string_view(level_name, dest);
+        }
+        else
+        {
+            fmt_helper::append_string_view(level_name, dest);
+        }
+    }
+};
+
+// short log level appender
+class short_level_formatter : public flag_formatter
+{
+public:
+    explicit short_level_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        string_view_t level_name{level::to_short_c_str(msg.level)};
+        scoped_pad p(level_name, padinfo_, dest);
+        fmt_helper::append_string_view(level_name, dest);
+    }
+};
+
+///////////////////////////////////////////////////////////////////////
+// Date time pattern appenders
+///////////////////////////////////////////////////////////////////////
+
+static const char *ampm(const tm &t)
+{
+    return t.tm_hour >= 12 ? "PM" : "AM";
+}
+
+static int to12h(const tm &t)
+{
+    return t.tm_hour > 12 ? t.tm_hour - 12 : t.tm_hour;
+}
+
+// Abbreviated weekday name
+static const char *days[]{"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
+class a_formatter : public flag_formatter
+{
+public:
+    explicit a_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        string_view_t field_value{days[tm_time.tm_wday]};
+        scoped_pad p(field_value, padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Full weekday name
+static const char *full_days[]{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
+class A_formatter : public flag_formatter
+{
+public:
+    explicit A_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        string_view_t field_value{full_days[tm_time.tm_wday]};
+        scoped_pad p(field_value, padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Abbreviated month
+static const char *months[]{"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec"};
+class b_formatter : public flag_formatter
+{
+public:
+    explicit b_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        string_view_t field_value{months[tm_time.tm_mon]};
+        scoped_pad p(field_value, padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Full month name
+static const char *full_months[]{
+    "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
+class B_formatter : public flag_formatter
+{
+public:
+    explicit B_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        string_view_t field_value{full_months[tm_time.tm_mon]};
+        scoped_pad p(field_value, padinfo_, dest);
+        fmt_helper::append_string_view(field_value, dest);
+    }
+};
+
+// Date and time representation (Thu Aug 23 15:35:46 2014)
+class c_formatter final : public flag_formatter
+{
+public:
+    explicit c_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 24;
+        scoped_pad p(field_size, padinfo_, dest);
+
+        fmt_helper::append_string_view(days[tm_time.tm_wday], dest);
+        dest.push_back(' ');
+        fmt_helper::append_string_view(months[tm_time.tm_mon], dest);
+        dest.push_back(' ');
+        fmt_helper::append_int(tm_time.tm_mday, dest);
+        dest.push_back(' ');
+        // time
+
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+        dest.push_back(' ');
+        fmt_helper::append_int(tm_time.tm_year + 1900, dest);
+    }
+};
+
+// year - 2 digit
+class C_formatter final : public flag_formatter
+{
+public:
+    explicit C_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_year % 100, dest);
+    }
+};
+
+// Short MM/DD/YY date, equivalent to %m/%d/%y 08/23/01
+class D_formatter final : public flag_formatter
+{
+public:
+    explicit D_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 10;
+        scoped_pad p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(tm_time.tm_mon + 1, dest);
+        dest.push_back('/');
+        fmt_helper::pad2(tm_time.tm_mday, dest);
+        dest.push_back('/');
+        fmt_helper::pad2(tm_time.tm_year % 100, dest);
+    }
+};
+
+// year - 4 digit
+class Y_formatter final : public flag_formatter
+{
+public:
+    explicit Y_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 4;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::append_int(tm_time.tm_year + 1900, dest);
+    }
+};
+
+// month 1-12
+class m_formatter final : public flag_formatter
+{
+public:
+    explicit m_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_mon + 1, dest);
+    }
+};
+
+// day of month 1-31
+class d_formatter final : public flag_formatter
+{
+public:
+    explicit d_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_mday, dest);
+    }
+};
+
+// hours in 24 format 0-23
+class H_formatter final : public flag_formatter
+{
+public:
+    explicit H_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+    }
+};
+
+// hours in 12 format 1-12
+class I_formatter final : public flag_formatter
+{
+public:
+    explicit I_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::pad2(to12h(tm_time), dest);
+    }
+};
+
+// minutes 0-59
+class M_formatter final : public flag_formatter
+{
+public:
+    explicit M_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_min, dest);
+    }
+};
+
+// seconds 0-59
+class S_formatter final : public flag_formatter
+{
+public:
+    explicit S_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+    }
+};
+
+// milliseconds
+class e_formatter final : public flag_formatter
+{
+public:
+    explicit e_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        auto millis = fmt_helper::time_fraction<std::chrono::milliseconds>(msg.time);
+        if (padinfo_.enabled())
+        {
+            const size_t field_size = 3;
+            scoped_pad p(field_size, padinfo_, dest);
+            fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
+        }
+        else
+        {
+            fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
+        }
+    }
+};
+
+// microseconds
+class f_formatter final : public flag_formatter
+{
+public:
+    explicit f_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        auto micros = fmt_helper::time_fraction<std::chrono::microseconds>(msg.time);
+        if (padinfo_.enabled())
+        {
+            const size_t field_size = 6;
+            scoped_pad p(field_size, padinfo_, dest);
+            fmt_helper::pad6(static_cast<size_t>(micros.count()), dest);
+        }
+        else
+        {
+            fmt_helper::pad6(static_cast<size_t>(micros.count()), dest);
+        }
+    }
+};
+
+// nanoseconds
+class F_formatter final : public flag_formatter
+{
+public:
+    explicit F_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        auto ns = fmt_helper::time_fraction<std::chrono::nanoseconds>(msg.time);
+        if (padinfo_.enabled())
+        {
+            const size_t field_size = 9;
+            scoped_pad p(field_size, padinfo_, dest);
+            fmt_helper::pad9(static_cast<size_t>(ns.count()), dest);
+        }
+        else
+        {
+            fmt_helper::pad9(static_cast<size_t>(ns.count()), dest);
+        }
+    }
+};
+
+// seconds since epoch
+class E_formatter final : public flag_formatter
+{
+public:
+    explicit E_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 10;
+        scoped_pad p(field_size, padinfo_, dest);
+        auto duration = msg.time.time_since_epoch();
+        auto seconds = std::chrono::duration_cast<std::chrono::seconds>(duration).count();
+        fmt_helper::append_int(seconds, dest);
+    }
+};
+
+// AM/PM
+class p_formatter final : public flag_formatter
+{
+public:
+    explicit p_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 2;
+        scoped_pad p(field_size, padinfo_, dest);
+        fmt_helper::append_string_view(ampm(tm_time), dest);
+    }
+};
+
+// 12 hour clock 02:55:02 pm
+class r_formatter final : public flag_formatter
+{
+public:
+    explicit r_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 11;
+        scoped_pad p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(to12h(tm_time), dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+        dest.push_back(' ');
+        fmt_helper::append_string_view(ampm(tm_time), dest);
+    }
+};
+
+// 24-hour HH:MM time, equivalent to %H:%M
+class R_formatter final : public flag_formatter
+{
+public:
+    explicit R_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 5;
+        scoped_pad p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+    }
+};
+
+// ISO 8601 time format (HH:MM:SS), equivalent to %H:%M:%S
+class T_formatter final : public flag_formatter
+{
+public:
+    explicit T_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 8;
+        scoped_pad p(field_size, padinfo_, dest);
+
+        fmt_helper::pad2(tm_time.tm_hour, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_min, dest);
+        dest.push_back(':');
+        fmt_helper::pad2(tm_time.tm_sec, dest);
+    }
+};
+
+// ISO 8601 offset from UTC in timezone (+-HH:MM)
+class z_formatter final : public flag_formatter
+{
+public:
+    explicit z_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    const std::chrono::seconds cache_refresh = std::chrono::seconds(5);
+
+    z_formatter() = default;
+    z_formatter(const z_formatter &) = delete;
+    z_formatter &operator=(const z_formatter &) = delete;
+
+    void format(const details::log_msg &msg, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 6;
+        scoped_pad p(field_size, padinfo_, dest);
+
+#ifdef _WIN32
+        int total_minutes = get_cached_offset(msg, tm_time);
+#else
+        // No need to chache under gcc,
+        // it is very fast (already stored in tm.tm_gmtoff)
+        (void)(msg);
+        int total_minutes = os::utc_minutes_offset(tm_time);
+#endif
+        bool is_negative = total_minutes < 0;
+        if (is_negative)
+        {
+            total_minutes = -total_minutes;
+            dest.push_back('-');
+        }
+        else
+        {
+            dest.push_back('+');
+        }
+
+        fmt_helper::pad2(total_minutes / 60, dest); // hours
+        dest.push_back(':');
+        fmt_helper::pad2(total_minutes % 60, dest); // minutes
+    }
+
+private:
+    log_clock::time_point last_update_{std::chrono::seconds(0)};
+#ifdef _WIN32
+    int offset_minutes_{0};
+
+    int get_cached_offset(const log_msg &msg, const std::tm &tm_time)
+    {
+        if (msg.time - last_update_ >= cache_refresh)
+        {
+            offset_minutes_ = os::utc_minutes_offset(tm_time);
+            last_update_ = msg.time;
+        }
+        return offset_minutes_;
+    }
+#endif
+};
+
+// Thread id
+class t_formatter final : public flag_formatter
+{
+public:
+    explicit t_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        if (padinfo_.enabled())
+        {
+            const auto field_size = fmt_helper::count_digits(msg.thread_id);
+            scoped_pad p(field_size, padinfo_, dest);
+            fmt_helper::append_int(msg.thread_id, dest);
+        }
+        else
+        {
+            fmt_helper::append_int(msg.thread_id, dest);
+        }
+    }
+};
+
+// Current pid
+class pid_formatter final : public flag_formatter
+{
+public:
+    explicit pid_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        const auto pid = static_cast<uint32_t>(details::os::pid());
+        if (padinfo_.enabled())
+        {
+            auto field_size = fmt_helper::count_digits(pid);
+            scoped_pad p(field_size, padinfo_, dest);
+            fmt_helper::append_int(pid, dest);
+        }
+        else
+        {
+            fmt_helper::append_int(pid, dest);
+        }
+    }
+};
+
+class v_formatter final : public flag_formatter
+{
+public:
+    explicit v_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        if (padinfo_.enabled())
+        {
+            scoped_pad p(msg.payload, padinfo_, dest);
+            fmt_helper::append_string_view(msg.payload, dest);
+        }
+        else
+        {
+            fmt_helper::append_string_view(msg.payload, dest);
+        }
+    }
+};
+
+class ch_formatter final : public flag_formatter
+{
+public:
+    explicit ch_formatter(char ch)
+        : ch_(ch)
+    {
+    }
+
+    void format(const details::log_msg &, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        const size_t field_size = 1;
+        scoped_pad p(field_size, padinfo_, dest);
+        dest.push_back(ch_);
+    }
+
+private:
+    char ch_;
+};
+
+// aggregate user chars to display as is
+class aggregate_formatter final : public flag_formatter
+{
+public:
+    aggregate_formatter() = default;
+
+    void add_ch(char ch)
+    {
+        str_ += ch;
+    }
+    void format(const details::log_msg &, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        fmt_helper::append_string_view(str_, dest);
+    }
+
+private:
+    std::string str_;
+};
+
+// mark the color range. expect it to be in the form of "%^colored text%$"
+class color_start_formatter final : public flag_formatter
+{
+public:
+    explicit color_start_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        msg.color_range_start = dest.size();
+    }
+};
+class color_stop_formatter final : public flag_formatter
+{
+public:
+    explicit color_stop_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        msg.color_range_end = dest.size();
+    }
+};
+
+// print source location
+class source_location_formatter final : public flag_formatter
+{
+public:
+    explicit source_location_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+        if (padinfo_.enabled())
+        {
+            const auto text_size = std::char_traits<char>::length(msg.source.filename) + fmt_helper::count_digits(msg.source.line) + 1;
+            scoped_pad p(text_size, padinfo_, dest);
+            fmt_helper::append_string_view(msg.source.filename, dest);
+            dest.push_back(':');
+            fmt_helper::append_int(msg.source.line, dest);
+        }
+        else
+        {
+            fmt_helper::append_string_view(msg.source.filename, dest);
+            dest.push_back(':');
+            fmt_helper::append_int(msg.source.line, dest);
+        }
+    }
+};
+// print source filename
+class source_filename_formatter final : public flag_formatter
+{
+public:
+    explicit source_filename_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+        scoped_pad p(msg.source.filename, padinfo_, dest);
+        fmt_helper::append_string_view(msg.source.filename, dest);
+    }
+};
+
+class source_linenum_formatter final : public flag_formatter
+{
+public:
+    explicit source_linenum_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+        if (padinfo_.enabled())
+        {
+            auto field_size = fmt_helper::count_digits(msg.source.line);
+            scoped_pad p(field_size, padinfo_, dest);
+            fmt_helper::append_int(msg.source.line, dest);
+        }
+        else
+        {
+            fmt_helper::append_int(msg.source.line, dest);
+        }
+    }
+};
+// print source funcname
+class source_funcname_formatter final : public flag_formatter
+{
+public:
+    explicit source_funcname_formatter(padding_info padinfo)
+        : flag_formatter(padinfo){};
+
+    void format(const details::log_msg &msg, const std::tm &, fmt::memory_buffer &dest) override
+    {
+        if (msg.source.empty())
+        {
+            return;
+        }
+        scoped_pad p(msg.source.funcname, padinfo_, dest);
+        fmt_helper::append_string_view(msg.source.funcname, dest);
+    }
+};
+
+// Full info formatter
+// pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] %v
+class full_formatter final : public flag_formatter
+{
+public:
+    explicit full_formatter(padding_info padinfo)
+        : flag_formatter(padinfo)
+    {
+    }
+
+    void format(const details::log_msg &msg, const std::tm &tm_time, fmt::memory_buffer &dest) override
+    {
+        using std::chrono::duration_cast;
+        using std::chrono::milliseconds;
+        using std::chrono::seconds;
+
+#ifndef SPDLOG_NO_DATETIME
+
+        // cache the date/time part for the next second.
+        auto duration = msg.time.time_since_epoch();
+        auto secs = duration_cast<seconds>(duration);
+
+        if (cache_timestamp_ != secs || cached_datetime_.size() == 0)
+        {
+            cached_datetime_.clear();
+            cached_datetime_.push_back('[');
+            fmt_helper::append_int(tm_time.tm_year + 1900, cached_datetime_);
+            cached_datetime_.push_back('-');
+
+            fmt_helper::pad2(tm_time.tm_mon + 1, cached_datetime_);
+            cached_datetime_.push_back('-');
+
+            fmt_helper::pad2(tm_time.tm_mday, cached_datetime_);
+            cached_datetime_.push_back(' ');
+
+            fmt_helper::pad2(tm_time.tm_hour, cached_datetime_);
+            cached_datetime_.push_back(':');
+
+            fmt_helper::pad2(tm_time.tm_min, cached_datetime_);
+            cached_datetime_.push_back(':');
+
+            fmt_helper::pad2(tm_time.tm_sec, cached_datetime_);
+            cached_datetime_.push_back('.');
+
+            cache_timestamp_ = secs;
+        }
+        fmt_helper::append_buf(cached_datetime_, dest);
+
+        auto millis = fmt_helper::time_fraction<milliseconds>(msg.time);
+        fmt_helper::pad3(static_cast<uint32_t>(millis.count()), dest);
+        dest.push_back(']');
+        dest.push_back(' ');
+
+#else // no datetime needed
+        (void)tm_time;
+#endif
+
+#ifndef SPDLOG_NO_NAME
+        if (!msg.logger_name->empty())
+        {
+            dest.push_back('[');
+            // fmt_helper::append_str(*msg.logger_name, dest);
+            fmt_helper::append_string_view(*msg.logger_name, dest);
+            dest.push_back(']');
+            dest.push_back(' ');
+        }
+#endif
+
+        dest.push_back('[');
+        // wrap the level name with color
+        msg.color_range_start = dest.size();
+        // fmt_helper::append_string_view(level::to_c_str(msg.level), dest);
+        fmt_helper::append_string_view(level::to_string_view(msg.level), dest);
+        msg.color_range_end = dest.size();
+        dest.push_back(']');
+        dest.push_back(' ');
+
+        // add source location if present
+        if (!msg.source.empty())
+        {
+            dest.push_back('[');
+            fmt_helper::append_string_view(msg.source.filename, dest);
+            dest.push_back(':');
+            fmt_helper::append_int(msg.source.line, dest);
+            dest.push_back(']');
+            dest.push_back(' ');
+        }
+        // fmt_helper::append_string_view(msg.msg(), dest);
+        fmt_helper::append_string_view(msg.payload, dest);
+    }
+
+private:
+    std::chrono::seconds cache_timestamp_{0};
+    fmt::basic_memory_buffer<char, 128> cached_datetime_;
+};
+
+} // namespace details
+
+
+ pattern_formatter::pattern_formatter(
+        std::string pattern, pattern_time_type time_type, std::string eol)
+        : pattern_(std::move(pattern))
+        , eol_(std::move(eol))
+        , pattern_time_type_(time_type)
+        , last_log_secs_(0)
+    {
+        std::memset(&cached_tm_, 0, sizeof(cached_tm_));
+        compile_pattern_(pattern_);
+    }
+
+    // use by default full formatter for if pattern is not given
+    pattern_formatter::pattern_formatter(pattern_time_type time_type, std::string eol)
+        : pattern_("%+")
+        , eol_(std::move(eol))
+        , pattern_time_type_(time_type)
+        , last_log_secs_(0)
+    {
+        std::memset(&cached_tm_, 0, sizeof(cached_tm_));
+        formatters_.push_back(details::make_unique<details::full_formatter>(details::padding_info{}));
+    }
+
+    
+    std::unique_ptr<formatter> pattern_formatter::clone() const
+    {
+        return details::make_unique<pattern_formatter>(pattern_, pattern_time_type_, eol_);
+    }
+
+    void pattern_formatter::format(const details::log_msg &msg, fmt::memory_buffer &dest)
+    {
+#ifndef SPDLOG_NO_DATETIME
+        auto secs = std::chrono::duration_cast<std::chrono::seconds>(msg.time.time_since_epoch());
+        if (secs != last_log_secs_)
+        {
+            cached_tm_ = get_time_(msg);
+            last_log_secs_ = secs;
+        }
+#endif
+        for (auto &f : formatters_)
+        {
+            f->format(msg, cached_tm_, dest);
+        }
+        // write eol
+        details::fmt_helper::append_string_view(eol_, dest);
+    }
+
+    std::tm pattern_formatter::get_time_(const details::log_msg &msg)
+    {
+        if (pattern_time_type_ == pattern_time_type::local)
+        {
+            return details::os::localtime(log_clock::to_time_t(msg.time));
+        }
+        return details::os::gmtime(log_clock::to_time_t(msg.time));
+    }
+
+    void pattern_formatter::handle_flag_(char flag, details::padding_info padding)
+    {
+        switch (flag)
+        {
+
+        case ('+'): // default formatter
+            formatters_.push_back(details::make_unique<details::full_formatter>(padding));
+            break;
+
+        case 'n': // logger name
+            formatters_.push_back(details::make_unique<details::name_formatter>(padding));
+            break;
+
+        case 'l': // level
+            formatters_.push_back(details::make_unique<details::level_formatter>(padding));
+            break;
+
+        case 'L': // short level
+            formatters_.push_back(details::make_unique<details::short_level_formatter>(padding));
+            break;
+
+        case ('t'): // thread id
+            formatters_.push_back(details::make_unique<details::t_formatter>(padding));
+            break;
+
+        case ('v'): // the message text
+            formatters_.push_back(details::make_unique<details::v_formatter>(padding));
+            break;
+
+        case ('a'): // weekday
+            formatters_.push_back(details::make_unique<details::a_formatter>(padding));
+            break;
+
+        case ('A'): // short weekday
+            formatters_.push_back(details::make_unique<details::A_formatter>(padding));
+            break;
+
+        case ('b'):
+        case ('h'): // month
+            formatters_.push_back(details::make_unique<details::b_formatter>(padding));
+            break;
+
+        case ('B'): // short month
+            formatters_.push_back(details::make_unique<details::B_formatter>(padding));
+            break;
+
+        case ('c'): // datetime
+            formatters_.push_back(details::make_unique<details::c_formatter>(padding));
+            break;
+
+        case ('C'): // year 2 digits
+            formatters_.push_back(details::make_unique<details::C_formatter>(padding));
+            break;
+
+        case ('Y'): // year 4 digits
+            formatters_.push_back(details::make_unique<details::Y_formatter>(padding));
+            break;
+
+        case ('D'):
+        case ('x'): // datetime MM/DD/YY
+            formatters_.push_back(details::make_unique<details::D_formatter>(padding));
+            break;
+
+        case ('m'): // month 1-12
+            formatters_.push_back(details::make_unique<details::m_formatter>(padding));
+            break;
+
+        case ('d'): // day of month 1-31
+            formatters_.push_back(details::make_unique<details::d_formatter>(padding));
+            break;
+
+        case ('H'): // hours 24
+            formatters_.push_back(details::make_unique<details::H_formatter>(padding));
+            break;
+
+        case ('I'): // hours 12
+            formatters_.push_back(details::make_unique<details::I_formatter>(padding));
+            break;
+
+        case ('M'): // minutes
+            formatters_.push_back(details::make_unique<details::M_formatter>(padding));
+            break;
+
+        case ('S'): // seconds
+            formatters_.push_back(details::make_unique<details::S_formatter>(padding));
+            break;
+
+        case ('e'): // milliseconds
+            formatters_.push_back(details::make_unique<details::e_formatter>(padding));
+            break;
+
+        case ('f'): // microseconds
+            formatters_.push_back(details::make_unique<details::f_formatter>(padding));
+            break;
+
+        case ('F'): // nanoseconds
+            formatters_.push_back(details::make_unique<details::F_formatter>(padding));
+            break;
+
+        case ('E'): // seconds since epoch
+            formatters_.push_back(details::make_unique<details::E_formatter>(padding));
+            break;
+
+        case ('p'): // am/pm
+            formatters_.push_back(details::make_unique<details::p_formatter>(padding));
+            break;
+
+        case ('r'): // 12 hour clock 02:55:02 pm
+            formatters_.push_back(details::make_unique<details::r_formatter>(padding));
+            break;
+
+        case ('R'): // 24-hour HH:MM time
+            formatters_.push_back(details::make_unique<details::R_formatter>(padding));
+            break;
+
+        case ('T'):
+        case ('X'): // ISO 8601 time format (HH:MM:SS)
+            formatters_.push_back(details::make_unique<details::T_formatter>(padding));
+            break;
+
+        case ('z'): // timezone
+            formatters_.push_back(details::make_unique<details::z_formatter>(padding));
+            break;
+
+        case ('P'): // pid
+            formatters_.push_back(details::make_unique<details::pid_formatter>(padding));
+            break;
+
+        case ('^'): // color range start
+            formatters_.push_back(details::make_unique<details::color_start_formatter>(padding));
+            break;
+
+        case ('$'): // color range end
+            formatters_.push_back(details::make_unique<details::color_stop_formatter>(padding));
+            break;
+
+        case ('@'): // source location (filename:filenumber)
+            formatters_.push_back(details::make_unique<details::source_location_formatter>(padding));
+            break;
+
+        case ('s'): // source filename
+            formatters_.push_back(details::make_unique<details::source_filename_formatter>(padding));
+            break;
+
+        case ('#'): // source line number
+            formatters_.push_back(details::make_unique<details::source_linenum_formatter>(padding));
+            break;
+
+        case ('!'): // source funcname
+            formatters_.push_back(details::make_unique<details::source_funcname_formatter>(padding));
+            break;
+
+        case ('%'): // % char
+            formatters_.push_back(details::make_unique<details::ch_formatter>('%'));
+            break;
+
+        default: // Unknown flag appears as is
+            auto unknown_flag = details::make_unique<details::aggregate_formatter>();
+            unknown_flag->add_ch('%');
+            unknown_flag->add_ch(flag);
+            formatters_.push_back((std::move(unknown_flag)));
+            break;
+        }
+    }
+
+    // Extract given pad spec (e.g. %8X)
+    // Advance the given it pass the end of the padding spec found (if any)
+    // Return padding.
+    details::padding_info pattern_formatter::handle_padspec_(std::string::const_iterator &it, std::string::const_iterator end)
+    {
+        using details::padding_info;
+        using details::scoped_pad;
+        const size_t max_width = 128;
+        if (it == end)
+        {
+            return padding_info{};
+        }
+
+        padding_info::pad_side side;
+        switch (*it)
+        {
+        case '-':
+            side = padding_info::right;
+            ++it;
+            break;
+        case '=':
+            side = padding_info::center;
+            ++it;
+            break;
+        default:
+            side = details::padding_info::left;
+            break;
+        }
+
+        if (it == end || !std::isdigit(static_cast<unsigned char>(*it)))
+        {
+            return padding_info{0, side};
+        }
+
+        auto width = static_cast<size_t>(*it - '0');
+        for (++it; it != end && std::isdigit(static_cast<unsigned char>(*it)); ++it)
+        {
+            auto digit = static_cast<size_t>(*it - '0');
+            width = width * 10 + digit;
+        }
+        return details::padding_info{std::min<size_t>(width, max_width), side};
+    }
+
+    void pattern_formatter::compile_pattern_(const std::string &pattern)
+    {
+        auto end = pattern.end();
+        std::unique_ptr<details::aggregate_formatter> user_chars;
+        formatters_.clear();
+        for (auto it = pattern.begin(); it != end; ++it)
+        {
+            if (*it == '%')
+            {
+                if (user_chars) // append user chars found so far
+                {
+                    formatters_.push_back(std::move(user_chars));
+                }
+
+                auto padding = handle_padspec_(++it, end);
+
+                if (it != end)
+                {
+                    handle_flag_(*it, padding);
+                }
+                else
+                {
+                    break;
+                }
+            }
+            else // chars not following the % sign should be displayed as is
+            {
+                if (!user_chars)
+                {
+                    user_chars = details::make_unique<details::aggregate_formatter>();
+                }
+                user_chars->add_ch(*it);
+            }
+        }
+        if (user_chars) // append raw chars found so far
+        {
+            formatters_.push_back(std::move(user_chars));
+        }
+    }
+} // namespace spdlog
+
diff --git a/tests/includes.h b/tests/includes.h
index 54601602..26517922 100644
--- a/tests/includes.h
+++ b/tests/includes.h
@@ -11,7 +11,6 @@
 #include <string>
 
 #define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_DEBUG
-#define SPDLOG_ENABLE_MESSAGE_COUNTER
 
 #include "spdlog/spdlog.h"
 #include "spdlog/async.h"
diff --git a/tests/test_errors.cpp b/tests/test_errors.cpp
index 24075634..e675cfd3 100644
--- a/tests/test_errors.cpp
+++ b/tests/test_errors.cpp
@@ -41,13 +41,18 @@ TEST_CASE("default_error_handler", "[errors]]")
 struct custom_ex
 {
 };
+
+static void custom_handler(const std::string &msg)
+{
+    throw custom_ex();
+}
 TEST_CASE("custom_error_handler", "[errors]]")
 {
     prepare_logdir();
     std::string filename = "logs/simple_log.txt";
     auto logger = spdlog::create<spdlog::sinks::basic_file_sink_mt>("logger", filename, true);
     logger->flush_on(spdlog::level::info);
-    logger->set_error_handler([=](const std::string &) { throw custom_ex(); });
+    logger->set_error_handler(custom_handler);
     logger->info("Good message #1");
 
     REQUIRE_THROWS_AS(logger->info("Bad format msg {} {}", "xxx"), custom_ex);
@@ -59,7 +64,7 @@ TEST_CASE("default_error_handler2", "[errors]]")
 {
     spdlog::drop_all();
     auto logger = spdlog::create<failing_sink>("failed_logger");
-    logger->set_error_handler([=](const std::string &) { throw custom_ex(); });
+    logger->set_error_handler(custom_handler);
     REQUIRE_THROWS_AS(logger->info("Some message"), custom_ex);
 }
 
@@ -67,26 +72,26 @@ TEST_CASE("flush_error_handler", "[errors]]")
 {
     spdlog::drop_all();
     auto logger = spdlog::create<failing_sink>("failed_logger");
-    logger->set_error_handler([=](const std::string &) { throw custom_ex(); });
+    logger->set_error_handler(custom_handler);
     REQUIRE_THROWS_AS(logger->flush(), custom_ex);
 }
 
 TEST_CASE("async_error_handler", "[errors]]")
 {
     prepare_logdir();
-    std::string err_msg("log failed with some msg");
+    
 
     std::string filename = "logs/simple_async_log.txt";
     {
         spdlog::init_thread_pool(128, 1);
         auto logger = spdlog::create_async<spdlog::sinks::basic_file_sink_mt>("logger", filename, true);
-        logger->set_error_handler([=](const std::string &) {
+        logger->set_error_handler([](const std::string &) {
             std::ofstream ofs("logs/custom_err.txt");
             if (!ofs)
             {
                 throw std::runtime_error("Failed open logs/custom_err.txt");
             }
-            ofs << err_msg;
+            ofs << "log failed with some msg";
         });
         logger->info("Good message #1");
         logger->info("Bad format msg {} {}", "xxx");
@@ -95,27 +100,26 @@ TEST_CASE("async_error_handler", "[errors]]")
     }
     spdlog::init_thread_pool(128, 1);
     REQUIRE(count_lines(filename) == 2);
-    REQUIRE(file_contents("logs/custom_err.txt") == err_msg);
+    REQUIRE(file_contents("logs/custom_err.txt") == "log failed with some msg");
 }
 
 // Make sure async error handler is executed
 TEST_CASE("async_error_handler2", "[errors]]")
 {
-    prepare_logdir();
-    std::string err_msg("This is async handler error message");
+    prepare_logdir();    
     {
         spdlog::init_thread_pool(128, 1);
         auto logger = spdlog::create_async<failing_sink>("failed_logger");
-        logger->set_error_handler([=](const std::string &) {
+        logger->set_error_handler([](const std::string &) {
             std::ofstream ofs("logs/custom_err2.txt");
             if (!ofs)
                 throw std::runtime_error("Failed open logs/custom_err2.txt");
-            ofs << err_msg;
+            ofs << "handler error message";
         });
         logger->info("Hello failure");
         spdlog::drop("failed_logger"); // force logger to drain the queue and shutdown
     }
 
     spdlog::init_thread_pool(128, 1);
-    REQUIRE(file_contents("logs/custom_err2.txt") == err_msg);
+    REQUIRE(file_contents("logs/custom_err2.txt") == "handler error message");
 }
diff --git a/tests/test_misc.cpp b/tests/test_misc.cpp
index 1b880835..5f4c094c 100644
--- a/tests/test_misc.cpp
+++ b/tests/test_misc.cpp
@@ -107,8 +107,7 @@ TEST_CASE("clone-logger", "[clone]")
     cloned->info("Some message 2");
 
     auto test_sink = std::static_pointer_cast<sinks::test_sink_mt>(cloned->sinks()[0]);
-    REQUIRE(test_sink->msg_counter() == 2);
-
+    
     spdlog::drop_all();
 }
 
@@ -129,8 +128,7 @@ TEST_CASE("clone async", "[clone]")
 
     spdlog::details::os::sleep_for_millis(10);
 
-    auto test_sink = std::static_pointer_cast<sinks::test_sink_mt>(cloned->sinks()[0]);
-    REQUIRE(test_sink->msg_counter() == 2);
+    auto test_sink = std::static_pointer_cast<sinks::test_sink_mt>(cloned->sinks()[0]);    
 
     spdlog::drop_all();
 }
@@ -176,22 +174,6 @@ TEST_CASE("to_hex_no_delimiter", "[to_hex]")
     REQUIRE(ends_with(output, "0000: 090A0B0CFFFF" + std::string(spdlog::details::os::default_eol)));
 }
 
-TEST_CASE("message_counter", "[message_counter]")
-{
-    std::ostringstream oss;
-    auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
-    spdlog::logger oss_logger("oss", oss_sink);
-    oss_logger.set_pattern("%i %v");
-
-    oss_logger.info("Hello");
-    REQUIRE(oss.str() == "000001 Hello" + std::string(spdlog::details::os::default_eol));
-
-    oss.str("");
-    oss_logger.info("Hello again");
-
-    REQUIRE(oss.str() == "000002 Hello again" + std::string(spdlog::details::os::default_eol));
-}
-
 TEST_CASE("default logger API", "[default logger]")
 {
     std::ostringstream oss;