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114 lines
4.2 KiB
Markdown
114 lines
4.2 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](#benchmarks) 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.
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* Example: ```logger.info("Hello {} {:08x}!!", "world", 42);```
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* ostream call style: ```logger.info() << "Hello << "logger";```
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* **new!** Extremely fast asynchronous mode (optional) - use of lockfree queues and other tricks to reach millions of calls per second from multiple threads.
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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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* Severity based filtering - threshold levels can be modified in runtime.
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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 (the best of 3 runs for each logger):
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|threads|boost log|glog|g2log <sup>async mode</sup>|spdlog|spdlog <sup>async mode</sup>|
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|-------|:-------:|:-----:|------:|------:|------:|
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|1|4.779s|1.109s|3.155s|0.319s|0.212s
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|10|15.151ss|3.546s|3.500s|0.641s|0.199s|
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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 = "logs/spdlog_example";
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// Set log level to all loggers to DEBUG and above
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spd::set_level(spd::level::DEBUG);
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//Create console, multithreaded logger
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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("An info message example {}..", 1);
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console->info() << "Streams are supported too " << 1;
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console->info("Easy padding in numbers like {:08d}", 12);
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console->info("Support for int: {0:d}; hex: {0:x}; oct: {0:o}; bin: {0:b}", 42);
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console->info("Support for floats {:03.2f}", 1.23456);
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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 syntax documation here:
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//http://cppformat.readthedocs.org/en/stable/syntax.html
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//Create a file rotating logger with 5mb size max and 3 rotated files
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auto file_logger = spd::rotating_logger_mt("file_logger", filename, 1024 * 1024 * 5, 3);
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for(int i = 0; i < 10; ++i)
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file_logger->info("{} * {} equals {:>10}", i, i, i*i);
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//Customize msg format
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spd::set_pattern("*** [%H:%M:%S %z] [thread %t] %v ***");
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file_logger->info("This is another message with custom format");
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spd::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name) function");
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SPDLOG_TRACE(file_logger, "This is a trace message (only #ifdef _DEBUG)", 123);
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//
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// Asynchronous logging is easy..
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// Just call spdlog::set_async_mode(max_q_size) and all created loggers from now on will be asynchronous..
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//
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size_t q_size = 1048576; //queue size must be power of 2
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spdlog::set_async_mode(q_size);
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auto async_file= spd::daily_logger_st("async_file_logger", "logs/async_log.txt");
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async_file->info() << "This is async log.." << "Should be very fast!";
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//
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// syslog example
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//
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#ifdef __linux__
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auto syslog_logger = spd::syslog_logger("syslog");
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syslog_logger->warn("This is warning that will end up in syslog. This is Linux only!");
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#endif
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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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}
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```
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