103 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
# spdlog
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Very fast, header only, C++ logging library.
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## Install
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Just copy the files to your build tree and use a C++11 compiler
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## Tested on:
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* gcc 4.8.1 and above
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* clang 3.5
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* visual studio 2013
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* mingw with g++ 4.9.x
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##Features
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* Very fast - performance is the primary goal (see becnhmarks below).
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* Headers only.
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* No dependencies.
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* Cross platform - Linux / Windows on 32/64 bits.
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* **new**! Feature rich [cppfromat call style](http://cppformat.readthedocs.org/en/stable/syntax.html) using the excellent [cppformat](http://cppformat.github.io/) library:```logger.info("Hello {} !!", "world");```
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* ostream call style ```logger.info() << "Hello << "logger";```
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* Mixed cppformat/ostream call style ```logger.info("{} + {} = ", 1, 2) << "?";```
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* [Custom](https://github.com/gabime/spdlog/wiki/Custom-formatting) formatting.
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* Multi/Single threaded loggers.
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* Various log targets:
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    * Rotating log files.
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    * Daily log files.
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    * Console logging.
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    * Linux syslog.
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    * Easily extendable with custom log targets  (just implement a single function in the [sink](include/spdlog/sinks/sink.h) interface).
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* Optional, even faster, async logging .
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* Log levels.
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## Benchmarks
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Below are some [benchmarks](bench) comparing the time needed to log 1,000,000 lines to file under Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz:
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|threads|boost log|glog|g2log|spdlog|spdlog <sup>async mode</sup>|
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|-------|:-------:|:-----:|------:|------:|------:|
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|1|4.779s|1.109s|3.155s|0.947s|1.455s
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|10|15.151ss|3.546s|3.500s|1.549s|2.040s|
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## Usage Example
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```c++
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#include <iostream>
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#include "spdlog/spdlog.h"
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int main(int, char* [])
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{
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    namespace spd = spdlog;
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    try
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    {
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        std::string filename = "spdlog_example";
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        auto console = spd::stdout_logger_mt("console");
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        console->info("Welcome to spdlog!") ;
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        console->info("Creating file {}..", filename);
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        auto file_logger = spd::rotating_logger_mt("file_logger", filename, 1024 * 1024 * 5, 3);
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        file_logger->info("Log file message number", 1);
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        for (int i = 0; i < 100; ++i)
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        {
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            file_logger->info("{} * {} = {}, i, i, i*i );
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        }
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        console->info("Easy padding in numbers like {:08d}", 12);
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        console->info("int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
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        console->info("Positional args are {1} {0}..", "too", "supported): 
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        console->info("{:<30}", "left aligned");
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        console->info("{:>30}", "right aligned");
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        console->info("{:^30}", "centered");
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        //see cppformat's full docs here:
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        //http://cppformat.readthedocs.org/en/stable/syntax.html
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        // Change log level to all loggers to warning and above
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        spd::set_level(spd::level::WARN);
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        console->info("This should not be displayed");
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        console->warn("This should!");
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        spd::set_level(spd::level::INFO);
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        // Change format pattern to all loggers
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        spd::set_pattern(" **** %Y-%m-%d %H:%M:%S.%e %l **** %v");
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        spd::get("console")->info("This is another message with different format");
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    }
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    catch (const spd::spdlog_ex& ex)
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    {
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        std::cout << "Log failed: " << ex.what() << std::endl;
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    }
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    return 0;
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}
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```
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