spdlog/README.md
2014-11-04 01:49:51 +02:00

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# spdlog
Very fast, header only, C++ logging library.
## Install
Just copy the files to your build tree and use a C++11 compiler
## Tested on:
* gcc 4.8.1 and above
* clang 3.5
* visual studio 2013
##Features
* Very fast - performance is the primary goal (see becnhmarks below)
* Headers only
* No dependencies
* Cross platform - Linux / Windows on 32/64 bits
* Mult/Single threaded loggers
* Rotating log files
* Daily log files
* Console logging
* Optional async logging
* Logging levels
* Custom formatting with user defined patterns
## Benchmarks comparison
Here are some [benchmarks](bench-comparison) comparing spdlog vs boost log(1.56.0) on Ubuntu 64 bits, Intel i7-4770 CPU @ 3.40GHz.
The bench writes 1000,000 log lines to a rotating log file of size 10MB with 5 back rotated files.
The multi threaded test uses a shared logger object across 10 threads.
#### spdlog vs. boost - Single threaded
|library|log lines|threads|elapsed|
|-------|:-------:|:-----:|------:|
|*boost*|1000,000|1|**4.207s**|
|*spdlog*|1000,000|1|**0.975s**|
#### spdlog vs. boost - Multi threaded
|library|log lines|threads|elapsed|
|-------|:-------:|:-----:|------:|
|*boost*|1000,000|10|**6.592s**|
|*spdlog*|1000,000|10|**0.961s**|
## Usage Example
```c++
#include <iostream>
#include "spdlog/spdlog.h"
int main(int, char* [])
{
namespace spd = spdlog;
try
{
std::string filename = "spdlog_example";
auto console = spd::stdout_logger_mt("console");
console->info("Welcome to spdlog!") ;
console->info() << "Creating file " << filename << "..";
auto file_logger = spd::rotating_logger_mt("file_logger", filename, 1024 * 1024 * 5, 3);
file_logger->info("Log file message number", 1);
for (int i = 0; i < 100; ++i)
{
auto square = i*i;
file_logger->info() << i << '*' << i << '=' << square << " (" << "0x" << std::hex << square << ")";
}
// Change log level to all loggers to warning and above
spd::set_level(spd::level::WARN);
console->info("This should not be displayed");
console->warn("This should!");
spd::set_level(spd::level::INFO);
// Change format pattern to all loggers
spd::set_pattern(" **** %Y-%m-%d %H:%M:%S.%e %l **** %v");
spd::get("console")->info("This is another message with different format");
}
catch (const spd::spdlog_ex& ex)
{
std::cout << "Log failed: " << ex.what() << std::endl;
}
return 0;
}
```