spdlog

Install

Just copy the headers:

Or use your favorite package manager:

Platforms

Features

Benchmarks

Synchronous mode

Asynchronous mode

Usage Example

#include "spdlog/spdlog.h"
#include <iostream>
#include <memory>
void async_example();
void syslog_example();
void user_defined_example();
void err_handler_example();
namespace spd = spdlog;
int main(int, char*[])
{
 try
 {
 // Console logger with color
 auto console = spd::stdout_color_mt("console");
 console->info("Welcome to spdlog!");
 console->error("Some error message with arg{}..", 1);
	
 // 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");
	
	// Use global registry to retrieve loggers
 spd::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name) function");
 
 // Create basic file logger (not rotated)
 auto my_logger = spd::basic_logger_mt("basic_logger", "logs/basic.txt");
 my_logger->info("Some log message");
 // Create a file rotating logger with 5mb size max and 3 rotated files
 auto rotating_logger = spd::rotating_logger_mt("some_logger_name", "logs/mylogfile.txt", 1048576 * 5, 3);
 for (int i = 0; i < 10; ++i)
 rotating_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.txt", 2, 30);
 // trigger flush if the log severity is error or higher
 daily_logger->flush_on(spd::level::err);
 daily_logger->info(123.44);
 // Customize msg format for all messages
 spd::set_pattern("[%^+++%$] [%H:%M:%S %z] [thread %t] %v");
 console->info("This an info message with custom format (and custom color range between the '%^' and '%$')");
	console->error("This an error message with custom format (and custom color range between the '%^' and '%$')");
 // Runtime log levels
	spd::set_level(spd::level::info); //Set global log level to info
	console->debug("This message should not be displayed!");
	console->set_level(spd::level::debug); // Set specific logger's log level
	console->debug("This message should be displayed..");
 // 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);
 // Asynchronous logging is very fast..
 // Just call spdlog::set_async_mode(q_size) and all created loggers from now on will be asynchronous..
 async_example();
 // syslog example. linux/osx only
 syslog_example();
 // android example. compile with NDK
 android_example();
 // Log user-defined types example
 user_defined_example();
 // Change default log error handler
 err_handler_example();
 // Apply a function on all registered loggers
 spd::apply_all([&](std::shared_ptr<spd::logger> l)
 {
 l->info("End of example.");
 });
 // Release and close all loggers
 spd::drop_all();
 }
 // Exceptions will only be thrown upon failed logger or sink construction (not during logging)
 catch (const spd::spdlog_ex& ex)
 {
 std::cout << "Log init failed: " << ex.what() << std::endl;
 return 1;
 }
}
void async_example()
{
 size_t q_size = 4096; 
 spd::set_async_mode(q_size);
 auto async_file = spd::daily_logger_st("async_file_logger", "logs/async_log.txt");
 for (int i = 0; i < 100; ++i)
 async_file->info("Async message #{}", i);
}
//syslog example
void syslog_example()
{
#ifdef SPDLOG_ENABLE_SYSLOG 
 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..");
#endif
}
// user defined types logging by implementing operator<<
struct my_type
{
 int i;
 template<typename OStream>
 friend OStream& operator<<(OStream& os, const my_type &c)
 {
 return os << "[my_type i="<<c.i << "]";
 }
};
#include <spdlog/fmt/ostr.h> // must be included
void user_defined_example()
{
 spd::get("console")->info("user defined type: {}", my_type { 14 });
}
//
//custom error handler
//
void err_handler_example()
{	
	spd::set_error_handler([](const std::string& msg) {
		std::cerr << "my err handler: " << msg << std::endl;
	}); 
	// (or logger->set_error_handler(..) to set for specific logger)
}

Documentation