# spdlog Very fast, header only, C++ logging library. [![Build Status](https://travis-ci.org/gabime/spdlog.svg?branch=master)](https://travis-ci.org/gabime/spdlog)  [![Build status](https://ci.appveyor.com/api/projects/status/d2jnxclg20vd0o50?svg=true)](https://ci.appveyor.com/project/gabime/spdlog) ## Install #### Just copy the headers: * Copy the source [folder](https://github.com/gabime/spdlog/tree/master/include/spdlog) to your build tree and use a C++11 compiler. #### Or use your favorite package manager: * Ubuntu: `apt-get install libspdlog-dev` * Homebrew: `brew install spdlog` * FreeBSD: `cd /usr/ports/devel/spdlog/ && make install clean` * Fedora: `yum install spdlog` * Gentoo: `emerge dev-libs/spdlog` * Arch Linux: `yaourt -S spdlog-git` * vcpkg: `vcpkg install spdlog` ## Platforms * Linux, FreeBSD, Solaris, AIX * Windows (vc 2013+, cygwin) * Mac OSX (clang 3.5+) * Android ## Features * Very fast - performance is the primary goal (see [benchmarks](#benchmarks) below). * Headers only, just copy and use. * Feature rich [call style](#usage-example) using the excellent [fmt](https://github.com/fmtlib/fmt) library. * Fast asynchronous mode (optional) * [Custom](https://github.com/gabime/spdlog/wiki/3.-Custom-formatting) formatting. * Conditional Logging * Multi/Single threaded loggers. * Various log targets: * Rotating log files. * Daily log files. * Console logging (colors supported). * syslog. * Windows debugger (```OutputDebugString(..)```) * Easily extendable with custom log targets (just implement a single function in the [sink](include/spdlog/sinks/sink.h) interface). * Severity based filtering - threshold levels can be modified in runtime as well as in compile time. ## Benchmarks Below are some [benchmarks](https://github.com/gabime/spdlog/blob/v1.x/bench/bench.cpp) done in Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz #### Synchronous mode ``` ******************************************************************************* Single thread, 1,000,000 iterations ******************************************************************************* basic_st... Elapsed: 0.231041 4,328,228/sec rotating... Elapsed: 0.233466 4,283,282/sec daily_st... Elapsed: 0.244491 4,090,136/sec null_st... Elapsed: 0.162708 6,145,995/sec ******************************************************************************* 10 threads sharing same logger, 1,000,000 iterations ******************************************************************************* basic_mt... Elapsed: 0.854029 1,170,920/sec rotating_mt Elapsed: 0.867038 1,153,351/sec daily_mt... Elapsed: 0.869593 1,149,963/sec null_mt... Elapsed: 0.171215 2,033,537/sec ``` #### Asynchronous mode ``` ******************************************************************************* 10 threads sharing same logger, 1,000,000 iterations ******************************************************************************* async... Elapsed: 0.442731 2,258,706/sec async... Elapsed: 0.427072 2,341,527/sec async... Elapsed: 0.449768 2,223,369/sec ``` ## Usage #### Terminal logging ```c++ #include "spdlog/spdlog.h" #include "spdlog/sinks/stdout_color_sinks.h" void stdout_example() { // create color multi threaded logger auto console = spdlog::stdout_color_mt("console"); console->info("Welcome to spdlog!"); console->error("Some error message with arg: {}", 1); auto err_logger = spdlog::stderr_color_mt("stderr"); err_logger->error("Some error message"); // Formatting examples console->warn("Easy padding in numbers like {:08d}", 12); console->critical("Support for int: {0:d}; hex: {0:x}; oct: {0:o}; bin: {0:b}", 42); console->info("Support for floats {:03.2f}", 1.23456); console->info("Positional args are {1} {0}..", "too", "supported"); console->info("{:<30}", "left aligned"); spdlog::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name)"); // Runtime log levels spdlog::set_level(spdlog::level::info); // Set global log level to info console->debug("This message should not be displayed!"); console->set_level(spdlog::level::trace); // Set specific logger's log level console->debug("This message should be displayed.."); // Customize msg format for all loggers spdlog::set_pattern("[%H:%M:%S %z] [%n] [%^---%L---%$] [thread %t] %v"); console->info("This an info message with custom format"); // Compile time log levels // define SPDLOG_DEBUG_ON or SPDLOG_TRACE_ON SPDLOG_TRACE(console, "Enabled only #ifdef SPDLOG_TRACE_ON..{} ,{}", 1, 3.23); SPDLOG_DEBUG(console, "Enabled only #ifdef SPDLOG_DEBUG_ON.. {} ,{}", 1, 3.23); } ``` --- #### Simple file logger ```c++ #include "spdlog/sinks/basic_file_sink.h" void basic_logfile_example() { // Create basic file logger (not rotated) try { auto my_logger = spdlog::basic_logger_mt("basic_logger", "logs/basic-log.txt"); } catch (const spdlog::spdlog_ex &ex) { std::cout << "Log init failed: " << ex.what() << std::endl; return 1; } } ```
#### Rotating files ```c++ #include "spdlog/sinks/rotating_file_sink.h" void rotating_example() { // Create a file rotating logger with 5mb size max and 3 rotated files auto rotating_logger = spdlog::rotating_logger_mt("some_logger_name", "logs/rotating.txt", 1048576 * 5, 3); } ``` --- #### Daily files ```c++ #include "spdlog/sinks/daily_file_sink.h" void daily_example() { // Create a daily logger - a new file is created every day on 2:30am auto daily_logger = spdlog::daily_logger_mt("daily_logger", "logs/daily.txt", 2, 30); } ``` --- #### Asynchronous logging ```c++ #include "spdlog/async.h" void async_example() { // default thread pool settings can be modified *before* creating the async logger: // spdlog::init_thread_pool(32768, 1); // queue with 32k items and 1 backing thread. auto async_file = spdlog::basic_logger_mt("async_file_logger", "logs/async_log.txt"); // alternatively: // auto async_file = spdlog::create_async("async_file_logger", "logs/async_log.txt"); for (int i = 1; i < 101; ++i) { async_file->info("Async message #{}", i); } } ``` --- #### Multi sink with different formatting per target ```c++ // create logger with 2 targets with different log levels and formats. // the console will show only warnings or errors, while the file will log all. void multi_sink_example() { auto console_sink = std::make_shared(); console_sink->set_level(spdlog::level::warn); console_sink->set_pattern("[multi_sink_example] [%^%l%$] %v"); auto file_sink = std::make_shared("logs/multisink.txt", true); file_sink->set_level(spdlog::level::trace); spdlog::logger logger("multi_sink", {console_sink, file_sink}); logger.set_level(spdlog::level::debug); logger.warn("this should appear in both console and file"); logger.info("this message should not appear in the console, only in the file"); } ``` --- #### User defined types ```c++ // user defined types logging by implementing operator<< #include "spdlog/fmt/ostr.h" // must be included struct my_type { int i; template friend OStream &operator<<(OStream &os, const my_type &c) { return os << "[my_type i=" << c.i << "]"; } }; void user_defined_example() { spdlog::get("console")->info("user defined type: {}", my_type{14}); } ``` --- #### Custom error handler ```c++ void err_handler_example() { // can be set globally or per logger(logger->set_error_handler(..)) spdlog::set_error_handler([](const std::string &msg) { spdlog::get("console")->error("*** LOGGER ERROR ***: {}", msg); }); spdlog::get("console")->info("some invalid message to trigger an error {}{}{}{}", 3); } ``` --- #### syslog ```c++ #include "spdlog/sinks/syslog_sink.h" void syslog_example() { std::string ident = "spdlog-example"; auto syslog_logger = spdlog::syslog_logger("syslog", ident, LOG_PID); syslog_logger->warn("This is warning that will end up in syslog."); } ``` --- #### Android example ```c++ #incude "spdlog/sinks/android_sink.h" void android_example() { std::string tag = "spdlog-android"; auto android_logger = spdlog::android_logger("android", tag); android_logger->critical("Use \"adb shell logcat\" to view this message."); } ``` ## Documentation Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki/1.-QuickStart) pages.