spdlog/README.md

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
• mingw with g++ 4.9.x

##Features

• Very fast - performance is the primary goal (see becnhmarks below).
• Headers only.
• No dependencies.
• Cross platform - Linux / Windows on 32/64 bits.
• new! Feature rich cppfromat call style using the excellent cppformat library: logger.info("Hello {}+{}={}", 1, 2, 3);
• ostream call style ```logger.info() << "Hello << "logger";
• Custom formatting.
• Multi/Single threaded loggers.
• Various log targets:
  • Rotating log files.
  • Daily log files.
  • Console logging.
  • Linux syslog.
  • Easily extendable with custom log targets (just implement a single function in the sink interface).
• Optional, even faster, async logging .
• Log levels.

Benchmarks

Below are some benchmarks comparing the time needed to log 1,000,000 lines to file under Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz:

threads	boost log	glog	g2log	spdlog	spdlog async mode
1	4.779s	1.109s	3.155s	0.947s	1.455s
10	15.151ss	3.546s	3.500s	1.549s	2.040s

Usage Example

#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)
        {
            file_logger->info("{} * {} = {}, i, i, i*i );
        }
        
        
        console->info("Easy padding in numbers like {:08d}", 12);
        console->info("int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
        console->info("Positional args are {1} {0}..", "too", "supported): 
        
        console->info("{:<30}", "left aligned");
        console->info("{:>30}", "right aligned");
        console->info("{:^30}", "centered");
        
        //see cppformat's full docs here:
        //http://cppformat.readthedocs.org/en/stable/syntax.html
        
        // 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;
}