Very fast, header only, C++ logging library.
Just copy the source folder to your build tree and use a C++11 compiler
- Linux (gcc 4.8.1+, clang 3.5+)
- Windows (visual studio 2013+, mingw with g++ 4.9.1+)
- Mac OSX (clang 3.5+)
##Features
- Very fast - performance is the primary goal (see benchmarks below).
- Headers only.
- No dependencies - just copy and use.
- Feature rich call style using the excellent cppformat library.
- ostream call style is supported too.
- Extremely fast asynchronous mode (optional) - using lockfree queues and other tricks to reach millions of calls/sec.
- 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).
- Severity based filtering - threshold levels can be modified in runtime as well as in compile time.
Below are some benchmarks comparing popular log libraries under Ubuntu 64 bit, Intel i7-4770 CPU @ 3.40GHz
Time needed to log 1,000,000 lines in synchronous mode (in seconds, the best of 3 runs):
| threads | boost log | glog | easylogging | spdlog |
|---|---|---|---|---|
| 1 | 4.169s | 1.066s | 0.975s | 0.302s |
| 10 | 16.029 | 3.032s | 2.857s | 0.968s |
| 100 | 15.008 | 1.139s | 4.512s | 0.497s |
Time needed to log 1,000,000 lines in asynchronous mode, i.e. the time it takes to put them in the async queue (in seconds, the best of 3 runs):
| threads | g2log async logger | spdlog async mode |
|---|---|---|
| 1 | 1.850s | 0.216s |
| 10 | 0.943s | 0.173s |
| 100 | 0.959s | 0.202s |
#include <iostream>
#include "spdlog/spdlog.h"
int main(int, char* [])
{
namespace spd = spdlog;
try
{
//Create console, multithreaded logger
auto console = spd::stdout_logger_mt("console");
console->info("Welcome to spdlog!") ;
console->info("An info message example {}..", 1);
console->info() << "Streams are supported too " << 1;
//Formatting examples
console->info("Easy padding in numbers like {:08d}", 12);
console->info("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");
console->info("{:>30}", "right aligned");
console->info("{:^30}", "centered");
//
// Runtime log levels
//
spd::set_level(spd::level::info); //Set global log level to info
console->debug("This message shold not be displayed!");
console->set_level(spd::level::debug); // Set specific logger's log level
console->debug("Now it should..");
//
// Create a file rotating logger with 5mb size max and 3 rotated files
//
auto file_logger = spd::rotating_logger_mt("file_logger", "logs/mylogfile", 1048576 * 5, 3);
for(int i = 0; i < 10; ++i)
file_logger->info("{} * {} equals {:>10}", i, i, i*i);
//
// Create a daily logger - a new file is created every day on 2:30am
//
auto daily_logger = spd::daily_logger_mt("daily_logger", "logs/daily", 2, 30);
//
// Customize msg format for all messages
//
spd::set_pattern("*** [%H:%M:%S %z] [thread %t] %v ***");
file_logger->info("This is another message with custom format");
spd::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name) function");
//
// Compile time debug or trace macros.
// Enabled #ifdef SPDLOG_DEBUG_ON or #ifdef 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);
//
// Asynchronous logging is very fast..
// Just call spdlog::set_async_mode(q_size) and all created loggers from now on will be asynchronous..
//
size_t q_size = 1048576; //queue size must be power of 2
spdlog::set_async_mode(q_size);
auto async_file= spd::daily_logger_st("async_file_logger", "logs/async_log.txt");
async_file->info() << "This is async log.." << "Should be very fast!";
//
// syslog example. linux only..
//
#ifdef __linux__
std::string ident = "spdlog-example";
auto syslog_logger = spd::syslog_logger("syslog", ident, LOG_PID);
syslog_logger->warn("This is warning that will end up in syslog. This is Linux only!");
#endif
}
catch (const spd::spdlog_ex& ex)
{
std::cout << "Log failed: " << ex.what() << std::endl;
}
}
// Example of user defined class with operator<<
class some_class {};
std::ostream& operator<<(std::ostream& os, const some_class& c) { return os << "some_class"; }
void custom_class_example()
{
some_class c;
spdlog::get("console")->info("custom class with operator<<: {}..", c);
spdlog::get("console")->info() << "custom class with operator<<: " << c << "..";
}Documentation can be found in the wiki pages.