51工具盒子|---------------------|---------------------------------------------------------------------------------------------------------------------------------------------------|
| 1 2 3 4 5 6 | #include "spdlog/spdlog.h" int main() { //Use the default logger (stdout, multi-threaded, colored) spdlog::info("Hello, {}!", "World"); } |
spdlog 是一个仅有头文件的库。只需将 include下的文件复制到您的项目中并使用 C++11 编译器即可。
它使用了fmt库提供了类似 Python 的格式化 API （参见参考）：
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| 1 | logger->info("Hello {} {} !!", "param1", 123.4); |
spdlog 采用"包含您需要的内容"方法 - 您的代码应该包含实际需要的功能。
例如，如果您只需要旋转记录器，则需要包含" spdlog/sinks/rotating_file_sink.h "。
另一个示例是包含" spdlog/async.h "以获取异步日志记录功能。
基本示例 {#基本示例}
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | #include <iostream> #include "spdlog/spdlog.h" #include "spdlog/sinks/basic_file_sink.h" // support for basic file logging #include "spdlog/sinks/rotating_file_sink.h" // support for rotating file logging int main(int, char* []) { try { // Create basic file logger (not rotated) auto my_logger = spdlog::basic_logger_mt("basic_logger", "logs/basic.txt"); // create a file rotating logger with 5mb size max and 3 rotated files auto file_logger = spdlog::rotating_logger_mt("file_logger", "myfilename", 1024 * 1024 * 5, 3); } catch (const spdlog::spdlog_ex& ex) { std::cout << "Log initialization failed: " << ex.what() << std::endl; } } |
使用工厂方法创建异步记录器 {#使用工厂方法创建异步记录器}
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | #include <iostream> #include "spdlog/spdlog.h" #include "spdlog/async.h" //support for async logging. #include "spdlog/sinks/basic_file_sink.h" int main(int, char* []) { try { auto async_file = spdlog::basic_logger_mt<spdlog::async_factory>("async_file_logger", "logs/async_log.txt"); for (int i = 1; i < 101; ++i) { async_file->info("Async message #{}", i); } // Under VisualStudio, this must be called before main finishes to workaround a known VS issue spdlog::drop_all(); } catch (const spdlog::spdlog_ex& ex) { std::cout << "Log initialization failed: " << ex.what() << std::endl; } } |
创建异步记录器并更改线程池设置 {#创建异步记录器并更改线程池设置}
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | #include "spdlog/async.h" //support for async logging #include "spdlog/sinks/daily_file_sink.h" int main(int, char* []) { try { auto daily_sink = std::make_shared<spdlog::sinks::daily_file_sink_mt>("logfile", 23, 59); // default thread pool settings can be modified *before* creating the async logger: spdlog::init_thread_pool(10000, 1); // queue with 10K items and 1 backing thread. auto async_file = spdlog::basic_logger_mt<spdlog::async_factory>("async_file_logger", "logs/async_log.txt"); spdlog::drop_all(); } catch (const spdlog::spdlog_ex& ex) { std::cout << "Log initialization failed: " << ex.what() << std::endl; } } |
创建共享同一文件（接收器）又称类别的多个记录器 {#创建共享同一文件（接收器）又称类别的多个记录器}
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | #include <iostream> #include "spdlog/spdlog.h" #include "spdlog/sinks/daily_file_sink.h" int main(int, char* []) { try { auto daily_sink = std::make_shared<spdlog::sinks::daily_file_sink_mt>("logfile", 23, 59); // create synchronous loggers auto net_logger = std::make_shared<spdlog::logger>("net", daily_sink); auto hw_logger = std::make_shared<spdlog::logger>("hw", daily_sink); auto db_logger = std::make_shared<spdlog::logger>("db", daily_sink); net_logger->set_level(spdlog::level::critical); // independent levels hw_logger->set_level(spdlog::level::debug); // globally register the loggers so they can be accessed using spdlog::get(logger_name) spdlog::register_logger(net_logger); } catch (const spdlog::spdlog_ex& ex) { std::cout << "Log initialization failed: " << ex.what() << std::endl; } } |
创建一个具有多个接收器的记录器，每个接收器都有自己的格式和日志级别 {#创建一个具有多个接收器的记录器，每个接收器都有自己的格式和日志级别}
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | // // Logger with console and file output. // the console will show only warnings or worse, while the file will log all messages. // #include <iostream> #include "spdlog/spdlog.h" #include "spdlog/sinks/stdout_color_sinks.h" // or "../stdout_sinks.h" if no colors needed #include "spdlog/sinks/basic_file_sink.h" int main(int, char* []) { try { 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::sinks_init_list sink_list = { file_sink, console_sink }; spdlog::logger logger("multi_sink", sink_list.begin(), sink_list.end()); 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"); // or you can even set multi_sink logger as default logger spdlog::set_default_logger(std::make_shared<spdlog::logger>("multi_sink", spdlog::sinks_init_list({console_sink, file_sink}))); } catch (const spdlog::spdlog_ex& ex) { std::cout << "Log initialization failed: " << ex.what() << std::endl; } } |
记录宏 {#记录宏}
您可以在包含"spdlog.h"之前将 SPDLOG_ACTIVE_LEVEL 定义为所需的日志级别。
这将在编译时打开/关闭日志记录语句
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| 1 2 3 4 5 6 7 | #define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_DEBUG spdlog::set_level(spdlog::level::debug); // or spdlog::set_level(spdlog::level::trace); SPDLOG_LOGGER_TRACE(file_logger , "Some trace message that will not be evaluated.{} ,{}", 1, 3.23); SPDLOG_LOGGER_DEBUG(file_logger , "Some Debug message that will be evaluated.. {} ,{}", 1, 3.23); SPDLOG_DEBUG("Some debug message to default logger that will be evaluated"); |
请注意，spdlog::set_level还需要打印出调试或跟踪消息。
记录用户定义对象 {#记录用户定义对象}
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | #include "spdlog/spdlog.h" #include "spdlog/fmt/ostr.h" // must be included #include "spdlog/sinks/stdout_sinks.h" class some_class {}; std::ostream& operator<<(std::ostream& os, const some_class& c) { return os << "some_class"; } // fmt v10 and above requires `fmt::formatter<T>` extends `fmt::ostream_formatter`. // See: https://github.com/fmtlib/fmt/issues/3318 template <> struct fmt::formatter<some_class> : fmt::ostream_formatter {}; void custom_class_example() { some_class c; auto console = spdlog::stdout_logger_mt("console"); console->info("custom class with operator<<: {}..", c); } |
或者在需要高级格式化时使用捆绑的库：fmt
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | #include <iterator> #include "spdlog/spdlog.h" #include "spdlog/fmt/ostr.h" // must be included #include "spdlog/sinks/stdout_sinks.h" class some_class { int code; }; template<typename OStream> friend OStream &operator<<(OStream &os, const some_class& to_log) { fmt::format_to(std::ostream_iterator<char>(os), "{:04X}", to_log.code); return os; } void custom_class_example() { some_class c; c.code = 17; auto console = spdlog::stdout_logger_mt("console"); console->info("custom class with operator<< using fmt: {}..", c); } |
参考链接：https://github.com/gabime/spdlog/wiki/1.-QuickStart
