使用变长参数实现简单的日志类

做项目时候经常需要打印日志来输出一些重要的信息，自己实现了一个简单的日志类，记录下。

Log.h

#pragma once

class CVxILog
{
private:
    CVxILog();
    ~CVxILog();
public:
    static    CVxILog*        Instance()
    {
        static CVxILog    log;
        return &log;
    }

    void    AddLog(const char* msg);

    void    AddLogEx(const char* format, ...);
private:
    static const    char* m_pFileName;

    static CRITICAL_SECTION    s_cs;
};

#define WRITE_LOG(msg)                    CVxILog::Instance()->AddLog(msg)
#define WRITE_LOG_EX(format,...)    CVxILog::Instance()->AddLogEx(format,__VA_ARGS__)

Log.cpp

#include "stdafx.h"
#include "Log.h"
#include <fstream>

CRITICAL_SECTION    CVxILog::s_cs;

const char* CVxILog::m_pFileName = _T("Test.log");

#define MAX_LOG_LENGTH        1024        //最大Log长度

static void    WriteHeadStr(std::ofstream& out)
{
    SYSTEMTIME st = {0};
    GetLocalTime(&st);
    char timeStr[MAX_LOG_LENGTH] = {0};
    sprintf_s(timeStr,"[%d-%02d-%02d %02d:%02d:%02d] ",st.wYear,st.wMonth,st.wDay,st.wHour,st.wMinute,st.wSecond);
    out << timeStr;
}

CVxILog::CVxILog()
{
    ::InitializeCriticalSection(&s_cs);
}
CVxILog::~CVxILog()
{
    ::DeleteCriticalSection(&s_cs);
}

void    CVxILog::AddLog(const char* msg)
{
    ::EnterCriticalSection(&s_cs);
    std::ofstream    out;
    out.open(m_pFileName,std::ios_base::app|std::ios_base::out);
    if(out.is_open())
    {
        WriteHeadStr(out);
        out << msg << std::endl;
        out.close();
    }
    ::LeaveCriticalSection(&s_cs);
}

void    CVxILog::AddLogEx(const char* format, ...)
{
    ::EnterCriticalSection(&s_cs);
    std::ofstream    out;
    out.open(m_pFileName,std::ios_base::app|std::ios_base::out);
    if(out.is_open())
    {
        WriteHeadStr(out);

        va_list ap;
        va_start(ap,format);
        char msg[MAX_LOG_LENGTH];
        int size = vsnprintf_s(msg,MAX_LOG_LENGTH-1,format,ap);
        if(size > 0)
        {
            out << msg << std::endl;
        }
        va_end(ap);
        
        out.close();
    }
    ::LeaveCriticalSection(&s_cs);
}

使用时可以

WRITE_LOG("log test");
WRITE_LOG_EX("[%s],log test",__FUNCTION__);

基本满足使用，但是还有很多不足，欢迎大家批评指正