pid support (added the %P option to formatter)

include/spdlog/details/os.h

@@ -356,6 +356,17 @@ inline std::string errno_str(int err_num)
 #endif
 }
 
+inline int pid() 
+{
+
+#ifdef _WIN32
+    return ::_getpid();
+#else
+    return static_cast<int>(::getpid());
+#endif
+
+}
+
 } //os
 } //details
 } //spdlog

include/spdlog/details/pattern_formatter_impl.h

@@ -356,7 +356,7 @@ private:
 
 
 
-//Thread id
+// Thread id
 class t_formatter:public flag_formatter
 {
     void format(details::log_msg& msg, const std::tm&) override
@@ -365,6 +365,15 @@ class t_formatter:public flag_formatter
     }
 };
 
+// Current pid 
+class pid_formatter:public flag_formatter
+{
+    void format(details::log_msg& msg, const std::tm&) override
+    {
+        msg.formatted << details::os::pid(); 
+    }
+};
+
 
 class v_formatter:public flag_formatter
 {
@@ -453,6 +462,8 @@ class full_formatter:public flag_formatter
     }
 };
 
+
+
 }
 }
 ///////////////////////////////////////////////////////////////////////////////
@@ -611,6 +622,10 @@ inline void spdlog::pattern_formatter::handle_flag(char flag)
         _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::full_formatter()));
         break;
 
+    case ('P'):
+        _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::pid_formatter()));
+        break;
+
     default: //Unkown flag appears as is
         _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::ch_formatter('%')));
         _formatters.push_back(std::unique_ptr<details::flag_formatter>(new details::ch_formatter(flag)));