# spdlog
Very fast, header only, C++ logging library. [](https://travis-ci.org/gabime/spdlog) [](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 5,840,602/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 Example
```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);
}
#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;
}
}
#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);
}
#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);
}
#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<spdlog::async_factory>("async_file_logger", "logs/async_log.txt");
// alternatively:
// auto async_file = spdlog::create_async<spdlog::sinks::basic_file_sink_mt>("async_file_logger", "logs/async_log.txt");
for (int i = 1; i < 101; ++i)
{
async_file->info("Async message #{}", i);
}
}
// 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<spdlog::sinks::stdout_color_sink_mt>();
console_sink->set_level(spdlog::level::warn);
console_sink->set_pattern("[multi_sink_example] [%^%l%$] %v");
auto file_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("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 logging by implementing operator<<
#include "spdlog/fmt/ostr.h" // must be included
struct my_type
{
int i;
template<typename OStream>
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
//
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 example (linux/osx/freebsd)
#ifndef _WIN32
#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.");
}
#endif
// Android example
#if defined(__ANDROID__)
#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.");
}
#endif
```
## Documentation
Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki/1.-QuickStart) pages.