g_pLog

 g_pLog = new CLog("log");
 g_pLog->Enable();
 g_pScrLog = new CLog("data");
 g_pScrLog->Enable();
 CString srelog= _T("log...");
 g_pLog->WriteLogFile(srelog);

#include <sys/stat.h>
#include <fcntl.h>
#include <io.h>
#include <afxmt.h>
#define MAX_ROW 5000
/**********************************************************************************
程序在当前目录下生成日志文件夹（如果该文件夹存在，则不生成），
每天的日志放在一个以当天日期命名的文件夹中。
MAX_ROW       定义一个日志文件的最大行数，一个日志文件达到这个行数后即关闭，并创建一个新文件。
**********************************************************************************/
class CLog
{
public:
 CLog(char* directory);
 ~CLog();
public:
 void Disable();   // 关闭日志功能
 void Enable();   // 打开日志功能
 void WriteLogFile(const char* fmt, ... );// 写日志函数
 void DeleteLogFile();
protected:
 int NewLogFile();  // 创建新日志文件
 BOOL IsChangeDay();  // 判断是否跨天（凌晨0点）
 CString GetCurntTime(); // 获得当前时间字符串，格式为 200709061150
 BOOL DelTree(LPCTSTR lpszPath);
private:
 int m_filehandle;
 int m_row;
 int m_dirnum;
 int m_filenum;
 BOOL m_needlog;
 char m_sContent[1024*1024];
 CString m_strContent;
 CString m_sCurtTime;
 CString m_sYestady;
 CString m_sToday;
 CString m_sCurtDir;
 CString m_sLogDir;
 CString m_sLogDayDir;
 CCriticalSection m_cs;
};
extern CLog *g_pLog;
extern CLog *g_pScrLog;

#include "stdafx.h"
#include "Log.h"

#include <direct.h>

CLog *g_pLog;        // 日志类指针
CLog *g_pScrLog;    // 设备原始数据记录指针

/* ==============
创建日志文件

参数：
    directory 目录名称
返回值:
    无
*///=============
CLog::CLog(char* directory)
{
    m_row = 0;
    m_filehandle = 0;
    m_dirnum = 0;
    m_filenum = 0;
    m_sCurtTime = _T("");
    m_sToday = _T("");
    m_sYestady = _T("");
    m_sCurtDir = _T("");
    m_sLogDir = _T("");
    m_needlog = FALSE;

    GetCurrentDirectory(_MAX_PATH,m_sCurtDir.GetBuffer(_MAX_PATH));
    m_sCurtDir.ReleaseBuffer();

    CString sDirName;
    CFileFind f;
    BOOL bHasLogDir = FALSE;
    BOOL bFind = f.FindFile(m_sCurtDir + "\\*.*");  // 文件是否存在

    while (bFind)
    {
        bFind = f.FindNextFile();

        if (f.IsDots()) 
            continue;

        if (f.IsDirectory())
        {
            sDirName = f.GetFileName();
            sDirName.MakeLower();
            if (sDirName == (CString)directory)
            {
                bHasLogDir = TRUE;
                break;
            }
        }
    }

    m_sLogDir = m_sCurtDir + (CString)"\\" + (CString)directory;

    if (!bHasLogDir)
    {
        _mkdir(m_sLogDir);
    }

    CString strTime = GetCurntTime ();

    m_sToday = strTime.Mid(0,8);
}

CLog::~CLog()
{
    if(m_filehandle != 0)
        _close(m_filehandle);
}

/* ==============
创建日志文件

参数：
    无
返回值:
    0 成功.-1 失败
*///=============
int CLog::NewLogFile()
{
    CString strLogfileName;

    if (m_filenum > 0)
    {
        _close(m_filehandle);
    }

    strLogfileName = m_sLogDayDir + (CString)"\\" + m_sCurtTime + (CString)".Log";

    if ((m_filehandle=_open(strLogfileName, _O_WRONLY)) == -1)
    {
        if ((m_filehandle=_open(strLogfileName, _O_WRONLY|_O_CREAT|O_TRUNC, _S_IREAD|_S_IWRITE)) == -1)
        {
            printf("cannot create log file:%s\n",strLogfileName);
            return -1;
        }
    }
    
    m_filenum++;
    return 0;
}

/* ==============
判断是否跨天（凌晨0点）

参数：
    无
返回值:
    false 当天
    true 跨天
*///=============
BOOL CLog::IsChangeDay()
{
    m_sCurtTime  = GetCurntTime();
    m_sToday = m_sCurtTime.Mid(0,8);

    if (m_sToday != m_sYestady)
    {
        m_sYestady = m_sToday;
        m_sLogDayDir = m_sLogDir + (CString)"\\" + m_sToday;
        _mkdir(m_sLogDayDir);
        return TRUE;
    }

    return FALSE;
}

/* ==============
写日志函数

参数：
    要记录的内容
返回值:
    无
*///=============
void CLog::WriteLogFile(const char* fmt, ... )
{
    if (!m_needlog)
        return;

    m_cs.Lock();

    if (m_row >= MAX_ROW ||  IsChangeDay())
    {
        if (NewLogFile() == -1)
        {
            m_cs.Unlock();
            return;
        }
        m_row = 0;
    }

    va_list v_args;
    va_start(v_args,fmt);
    vsprintf( m_sContent, fmt, v_args );
    va_end( v_args );

    CString strTime;
    CTime cTime = CTime::GetCurrentTime();
    strTime = _T("20") + cTime.Format("%y-%m-%d %H:%M:%S");
    
    m_strContent = (CString)"[" + strTime + (CString)"]" + (CString)m_sContent + "\n";

    _write(m_filehandle, m_strContent, m_strContent.GetLength());
    m_row++;

    m_cs.Unlock();
}

/* ==============
获得当前时间字符串，格式为 20070906

参数：
    无
返回值:
    当前时间字符串
*///=============

CString CLog::GetCurntTime()
{
    CString strTime;

    CTime cTime = CTime::GetCurrentTime();
    strTime = _T("20") + cTime.Format("%y%m%d%H%M%S");

    return strTime;
}

/* ==============
 打开日志功能

参数：
无
返回值:
无
*///=============
void CLog::Enable()
{
    m_needlog = TRUE;
}

/* ==============
关闭日志功能

参数：
无
返回值:
无
*///=============
void CLog::Disable()
{
    m_needlog = FALSE;
}

/* ==============
删除7天前的日志

参数：
无
返回值:
无
*///=============
void CLog::DeleteLogFile()
{   
    CString iFlieName,iFlieName1,iToday,TStr;
    int k,k1,k2;
    char s[60] = {‘\0‘}; 
    TStr = GetCurntTime();
    iToday = TStr.Mid(0,8);
    CFileFind ff;   
    BOOL   bFound = ff.FindFile(m_sLogDir+"\\*",   0);   
    while(bFound)   
    {   
        bFound = ff.FindNextFile();

        if (ff.IsDots())
            continue;

        if (ff.IsDirectory())   
        {   
            // 这里是目录   
            iFlieName = ff.GetFilePath(); 
            iFlieName1 = iFlieName.Right(8);
            
            k = atoi(iToday)/100 - atoi(iFlieName1)/100;
            k1 =  atoi(iToday) - atoi(iFlieName1);
            k2 = 31 - (atoi(iFlieName1)%100) + (atoi(iToday)%100);
            _tcscpy( s , iFlieName.GetBuffer(iFlieName.GetLength()) ) ;
            if ((k>1)&&(k<12)) 
            {
                DelTree((LPCTSTR)s);
            }
            else if (k == 0)
            {
                if (k1 > 7)
                {
                    DelTree((LPCTSTR)s);
                }
            }
            else if (k == 1)
            {
                if (k2 > 7)
                {
                    DelTree((LPCTSTR)s);
                }
            }
            else
            {
                if ((atoi(iToday)/1000-atoi(iFlieName1)/1000)==1)
                {
                    if ((atoi(iFlieName1)%10000)/100 == 12)
                    {
                        if (k2 > 7)
                        {
                            DelTree((LPCTSTR)s);
                        }    
                    }
                    else
                    {
                        DelTree((LPCTSTR)s);
                    }
                }
                else
                {
                    DelTree((LPCTSTR)s);
                }
            }
        } 
    }   
    ff.Close();     
}

/* ==============
删除文件夹

参数：
文件夹的路径
返回值:
删除是否成功
*///=============
BOOL CLog::DelTree(LPCTSTR lpszPath)
{
    SHFILEOPSTRUCT FileOp;
    FileOp.fFlags = FOF_NOCONFIRMATION;
    FileOp.hNameMappings = NULL;
    FileOp.hwnd = NULL;
    FileOp.lpszProgressTitle = NULL;
    FileOp.pFrom = lpszPath;//路径名从何处来
    FileOp.pTo = NULL;//
    FileOp.wFunc = FO_DELETE;
    return SHFileOperation(&FileOp) == 0;
}