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263 lines
8.9 KiB
Markdown
263 lines
8.9 KiB
Markdown
# spdlog
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Very fast, header only, C++ logging library. [](https://travis-ci.org/gabime/spdlog) [](https://ci.appveyor.com/project/gabime/spdlog)
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## Install
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#### Just copy the headers:
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* Copy the source [folder](https://github.com/gabime/spdlog/tree/master/include/spdlog) to your build tree and use a C++11 compiler.
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#### Or use your favorite package manager:
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* Ubuntu: `apt-get install libspdlog-dev`
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* Homebrew: `brew install spdlog`
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* FreeBSD: `cd /usr/ports/devel/spdlog/ && make install clean`
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* Fedora: `yum install spdlog`
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* Gentoo: `emerge dev-libs/spdlog`
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* Arch Linux: `yaourt -S spdlog-git`
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* vcpkg: `vcpkg install spdlog`
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## Platforms
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* Linux, FreeBSD, Solaris, AIX
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* Windows (vc 2013+, cygwin)
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* Mac OSX (clang 3.5+)
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* Android
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## Features
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* Very fast - performance is the primary goal (see [benchmarks](#benchmarks) below).
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* Headers only, just copy and use.
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* Feature rich [call style](#usage-example) using the excellent [fmt](https://github.com/fmtlib/fmt) library.
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* Fast asynchronous mode (optional)
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* [Custom](https://github.com/gabime/spdlog/wiki/3.-Custom-formatting) formatting.
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* Conditional Logging
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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 (colors supported).
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* syslog.
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* Windows debugger (```OutputDebugString(..)```)
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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 as well as in compile time.
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## Benchmarks
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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
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#### Synchronous mode
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```
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*******************************************************************************
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Single thread, 1,000,000 iterations
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*******************************************************************************
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basic_st... Elapsed: 0.231041 4,328,228/sec
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rotating... Elapsed: 0.233466 4,283,282/sec
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daily_st... Elapsed: 0.244491 4,090,136/sec
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null_st... Elapsed: 0.162708 6,145,995/sec
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*******************************************************************************
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10 threads sharing same logger, 1,000,000 iterations
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*******************************************************************************
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basic_mt... Elapsed: 0.854029 1,170,920/sec
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rotating_mt Elapsed: 0.867038 1,153,351/sec
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daily_mt... Elapsed: 0.869593 1,149,963/sec
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null_mt... Elapsed: 0.171215 2,033,537/sec
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```
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#### Asynchronous mode
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```
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*******************************************************************************
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10 threads sharing same logger, 1,000,000 iterations
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*******************************************************************************
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async... Elapsed: 0.442731 2,258,706/sec
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async... Elapsed: 0.427072 2,341,527/sec
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async... Elapsed: 0.449768 2,223,369/sec
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```
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## Usage
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#### Terminal logging
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```c++
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#include "spdlog/spdlog.h"
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#include "spdlog/sinks/stdout_color_sinks.h"
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void stdout_example()
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{
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// create color multi threaded logger
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auto console = spdlog::stdout_color_mt("console");
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console->info("Welcome to spdlog!");
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console->error("Some error message with arg: {}", 1);
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auto err_logger = spdlog::stderr_color_mt("stderr");
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err_logger->error("Some error message");
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// Formatting examples
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console->warn("Easy padding in numbers like {:08d}", 12);
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console->critical("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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spdlog::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name)");
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// Runtime log levels
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spdlog::set_level(spdlog::level::info); // Set global log level to info
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console->debug("This message should not be displayed!");
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console->set_level(spdlog::level::trace); // Set specific logger's log level
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console->debug("This message should be displayed..");
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// Customize msg format for all loggers
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spdlog::set_pattern("[%H:%M:%S %z] [%n] [%^---%L---%$] [thread %t] %v");
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console->info("This an info message with custom format");
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// Compile time log levels
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// define SPDLOG_DEBUG_ON or SPDLOG_TRACE_ON
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SPDLOG_TRACE(console, "Enabled only #ifdef SPDLOG_TRACE_ON..{} ,{}", 1, 3.23);
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SPDLOG_DEBUG(console, "Enabled only #ifdef SPDLOG_DEBUG_ON.. {} ,{}", 1, 3.23);
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}
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```
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---
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#### Simple file logger
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```c++
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#include "spdlog/sinks/basic_file_sink.h"
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void basic_logfile_example()
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{
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// Create basic file logger (not rotated)
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try
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{
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auto my_logger = spdlog::basic_logger_mt("basic_logger", "logs/basic-log.txt");
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}
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catch (const spdlog::spdlog_ex &ex)
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{
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std::cout << "Log init failed: " << ex.what() << std::endl;
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return 1;
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}
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}
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```
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---
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#### Rotating files
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```c++
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#include "spdlog/sinks/rotating_file_sink.h"
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void rotating_example()
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{
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// Create a file rotating logger with 5mb size max and 3 rotated files
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auto rotating_logger = spdlog::rotating_logger_mt("some_logger_name", "logs/rotating.txt", 1048576 * 5, 3);
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}
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```
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---
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#### Daily files
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```c++
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#include "spdlog/sinks/daily_file_sink.h"
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void daily_example()
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{
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// Create a daily logger - a new file is created every day on 2:30am
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auto daily_logger = spdlog::daily_logger_mt("daily_logger", "logs/daily.txt", 2, 30);
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}
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```
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---
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#### Periodic flush
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```c++
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// periodically flush all *registered* loggers every 3 seconds:
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// warning: only use if all your loggers are thread safe!
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spdlog::flush_every(std::chrono::seconds(3));
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```
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---
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#### Asynchronous logging
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```c++
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#include "spdlog/async.h"
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void async_example()
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{
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// default thread pool settings can be modified *before* creating the async logger:
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// spdlog::init_thread_pool(8192, 1); // queue with 8k items and 1 backing thread.
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auto async_file = spdlog::basic_logger_mt<spdlog::async_factory>("async_file_logger", "logs/async_log.txt");
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// alternatively:
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// auto async_file = spdlog::create_async<spdlog::sinks::basic_file_sink_mt>("async_file_logger", "logs/async_log.txt");
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}
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```
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---
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#### Logger with multi targets - each with different format and log level
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```c++
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// create logger with 2 targets with different log levels and formats.
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// the console will show only warnings or errors, while the file will log all.
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void multi_sink_example()
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{
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auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
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console_sink->set_level(spdlog::level::warn);
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console_sink->set_pattern("[multi_sink_example] [%^%l%$] %v");
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auto file_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("logs/multisink.txt", true);
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file_sink->set_level(spdlog::level::trace);
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spdlog::logger logger("multi_sink", {console_sink, file_sink});
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logger.set_level(spdlog::level::debug);
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logger.warn("this should appear in both console and file");
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logger.info("this message should not appear in the console, only in the file");
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}
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```
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---
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#### User defined types
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```c++
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// user defined types logging by implementing operator<<
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#include "spdlog/fmt/ostr.h" // must be included
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struct my_type
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{
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int i;
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template<typename OStream>
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friend OStream &operator<<(OStream &os, const my_type &c)
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{
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return os << "[my_type i=" << c.i << "]";
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}
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};
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void user_defined_example()
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{
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spdlog::get("console")->info("user defined type: {}", my_type{14});
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}
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```
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---
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#### Custom error handler
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```c++
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void err_handler_example()
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{
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// can be set globally or per logger(logger->set_error_handler(..))
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spdlog::set_error_handler([](const std::string &msg) { spdlog::get("console")->error("*** LOGGER ERROR ***: {}", msg); });
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spdlog::get("console")->info("some invalid message to trigger an error {}{}{}{}", 3);
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}
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```
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---
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#### syslog
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```c++
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#include "spdlog/sinks/syslog_sink.h"
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void syslog_example()
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{
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std::string ident = "spdlog-example";
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auto syslog_logger = spdlog::syslog_logger("syslog", ident, LOG_PID);
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syslog_logger->warn("This is warning that will end up in syslog.");
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}
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```
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---
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#### Android example
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```c++
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#incude "spdlog/sinks/android_sink.h"
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void android_example()
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{
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std::string tag = "spdlog-android";
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auto android_logger = spdlog::android_logger("android", tag);
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android_logger->critical("Use \"adb shell logcat\" to view this message.");
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}
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```
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## Documentation
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Documentation can be found in the [wiki](https://github.com/gabime/spdlog/wiki/1.-QuickStart) pages.
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