原文链接：

工具库1：封装一个日志库（linux)-CSDN博客

一、，需求
（1）封装一个c/c++日志库，提供格式打印接口，编写程序代码时方便使用；
（2） 格式打印接口支持可变参数；
（3）格式打印接口封装成可变参数宏，便于使用；

二，实现
（1）提供格式打印接口；
（2）日志等级分成三个级别，分别是错误、警告、普通信息；
（3）支持输出到终端，同时支持输出到指定日志文件；
（4）格式打印接口支持可变参数；
（5）打印字符串长度无限制；

三，源码
（1）messages.h
 

/**
*****************************************************************************
*  Copyright (C), 2023-2024
*
*  @file    messages.h
*  @brief   printf pretty
*
*
*  @author  sbinhuang
*  @date    2023-06-28
*  @version v1.0.0 20230628
*----------------------------------------------------------------------------
*  @note 历史版本   修改人员    修改日期      修改内容
*  @note v1.0    sbinhuang   2023-06-28   1.创建
*
*****************************************************************************
*/
#ifndef _SELF_UTILITY_MESSAGES_H_
#define _SELF_UTILITY_MESSAGES_H_
#include <iostream>
#include <fstream>namespace SelfUtility {
// message type
enum MessageType {NONE  = 0,ERROR = 1,WARN  = 2,INFO  = 3
};class Messages {public:// default close file and enable terminal outputstatic bool Init();// open log file// mode = true, open or create file and clear file content// mode = false, open or create file, doesn't clear file contentstatic bool OpenLogFile(const char *file_name, bool mode = 0);// close log filestatic bool CloseLogFile();// enable terminal outputstatic bool EnableTerminalOutput();// disable terminal outputstatic bool DisableTerminalOutput();// print message for variable argumentstatic bool Message(const MessageType &type, const char *file_name,int line_number, const char *format, ...);// print message for determine argumentstatic bool Message(const MessageType &type, const char *file_name,int line_number, const char *format);private:static std::ofstream _os;static bool _terminal_output;static bool _write_file;
};}  // namespace SelfUtility#define LOG_ERROR(format, ...) do { \SelfUtility::Messages::Message(SelfUtility::MessageType::ERROR, \__FILE__, __LINE__, format, __VA_ARGS__); \
} while (0)#define LOG_WARN(format, ...) do { \SelfUtility::Messages::Message(SelfUtility::MessageType::WARN, \__FILE__, __LINE__, format, __VA_ARGS__); \
} while (0)#define LOG_INFO(format, ...) do { \SelfUtility::Messages::Message(SelfUtility::MessageType::INFO, \__FILE__, __LINE__, format, __VA_ARGS__); \
} while (0)#define LOG_PRINT(format, ...) do { \SelfUtility::Messages::Message(SelfUtility::MessageType::NONE, \__FILE__, __LINE__, format, __VA_ARGS__); \
} while (0)#define LOG_INIT() do { \SelfUtility::Messages::Init(); \
} while (0)#endif  // _SELF_UTILITY_MESSAGES_H_

(2) messages.cpp

/**
*****************************************************************************
*  Copyright (C), 2023-2024
*
*  @file    messages.cpp
*  @brief   printf pretty
*
*
*  @author  sbinhuang
*  @date    2023-06-28
*  @version v1.0.0 20230628
*----------------------------------------------------------------------------
*  @note 历史版本   修改人员    修改日期      修改内容
*  @note v1.0    sbinhuang   2023-06-28   1.创建
*
*****************************************************************************
*/
#include "messages.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <iostream>
#include <fstream>
#include <string>using SelfUtility::MessageType;
using SelfUtility::Messages;// static variable define for class Messages
std::ofstream Messages::_os;
bool Messages::_write_file;
bool Messages::_terminal_output;// initial log print, default output terminal
bool Messages::Init() {if (_os.is_open()) _os.close();_terminal_output = true;_write_file = false;return true;
}// Open log file
// mode = true, open or create file and clear file content
// mode = false, open or create file, doesn't clear file content
bool Messages::OpenLogFile(const char *file_name, bool mode) {if (!file_name) {std::cout << "Log file name is null pointer!" << std::endl;return false;}// open fileif (true == mode) {_os.open(file_name, std::ios::out);} else {_os.open(file_name, std::ios::app);}if (!_os.is_open()) {std::cout << "File open failed!" << "(" << file_name<< ")" << std::endl;return false;}_write_file = true;return true;
}// close log file
bool Messages::CloseLogFile() {if (_os.is_open()) _os.close();_write_file = false;return true;
}// enable terminal output
bool Messages::EnableTerminalOutput() {_terminal_output = true;return true;
}// disable terminal output
bool Messages::DisableTerminalOutput() {_terminal_output = false;return true;
}// print message for variable argument
bool Messages::Message(const MessageType &type, const char *file_name,int line_number, const char *format, ...) {// print titleif (MessageType::ERROR == type) {if (true == _terminal_output) {if (file_name) {std::cout << "[" << file_name << ": "<< line_number << "]";}std::cout << "ERROR: ";}if (true == _write_file) {if (file_name) {_os << "[" << file_name << ": "<< line_number << "]";}_os << "ERROR: ";}} else if (MessageType::WARN == type) {if (true == _terminal_output) {if (file_name) {std::cout << "[" << file_name << ": "<< line_number << "]";}std::cout << "WARN: ";}if (true == _write_file) {if (file_name) {_os << "[" << file_name << ": "<< line_number << "]";}_os << "WARN: ";}} else if (MessageType::INFO == type) {if (true == _terminal_output) std::cout << "INFO: ";if (true == _write_file) std::cout << "INFO: ";}// print messagechar *buf = NULL;va_list arg_ptr;va_start(arg_ptr, format);vasprintf(&buf, format, arg_ptr);va_end(arg_ptr);if (true == _terminal_output) {std::cout << buf;}if (true == _write_file) {_os << buf;}free(buf);buf = NULL;return true;
}// print message for determine argument
bool Messages::Message(const MessageType &type, const char *file_name,int line_number, const char *format) {// print titleif (MessageType::ERROR == type) {if (true == _terminal_output) {if (file_name) {std::cout << "[" << file_name << ": "<< line_number << "]";}std::cout << "ERROR: ";}if (true == _write_file) {if (file_name) {_os << "[" << file_name << ": "<< line_number << "]";}_os << "ERROR: ";}} else if (MessageType::WARN == type) {if (true == _terminal_output) {if (file_name) {std::cout << "[" << file_name << ": "<< line_number << "]";}std::cout << "WARN: ";}if (true == _write_file) {if (file_name) {_os << "[" << file_name << ": "<< line_number << "]";}_os << "WARN: ";}} else if (MessageType::INFO == type) {if (true == _terminal_output) std::cout << "INFO: ";if (true == _write_file) std::cout << "INFO: ";}// print messageif (true == _terminal_output) std::cout << format;if (true == _write_file) _os << format;return true;
}