MFC 自己写的写日志文件功能

实现功能：每次写入内容到log文件中，且都是从后面追加的，如果文件大小超过500k,则清空内容重新写入

1.新建MFC工程

1）添加互斥文件

添加semaphoreclass.h文件

里面加入:

#ifndef _SEMAPHORECLASS_H_
#define _SEMAPHORECLASS_H_

class CSemaphoreClass
{
public:
	CSemaphoreClass();
	~CSemaphoreClass();

	void Lock();
	void Unlock();

private:
	CRITICAL_SECTION m_hSem;
};

class CAutoLock
{
public:
	CAutoLock(CSemaphoreClass *pCSem);
	~CAutoLock();

private:
	CSemaphoreClass *m_pAutoSem;
};
#endif//_SEMAPHORECLASS_H_

添加semaphoreclass.cpp，里面添加

#include "stdafx.h"
#include "semaphoreclass.h"


CSemaphoreClass::CSemaphoreClass()
{
	InitializeCriticalSection(&m_hSem);
}

CSemaphoreClass::~CSemaphoreClass()
{
	DeleteCriticalSection(&m_hSem); 
}

void CSemaphoreClass::Lock()
{
	EnterCriticalSection(&m_hSem);
}

void CSemaphoreClass::Unlock()
{
	LeaveCriticalSection(&m_hSem);
}


CAutoLock::CAutoLock( CSemaphoreClass *pCSem )
{
	ASSERT(pCSem);

	m_pAutoSem = pCSem;
	m_pAutoSem->Lock();
}

CAutoLock::~CAutoLock()
{
	ASSERT(m_pAutoSem);

	m_pAutoSem->Unlock();
	m_pAutoSem = NULL;
}

2.日志文件功能添加

添加log.h,里面加入

#ifndef _LOG_H_
#define _LOG_H_

#include <Windows.h>
#include <iostream>
using namespace std;

#define LOG_DIR           _T("Log\\")
#define LOG_FILE          _T("my.log")
#define LOG_SIZE          (500*1024)

class CLog
{
public:
	CLog();
	~CLog();

        static CString GetModuleFullPath(void);
        static void WriteLog(const char *pTemp);

};#define LOG CLog::WriteLog#endif//_LOG_H_

log.cpp中添加：

#include "stdafx.h"
#include "semaphoreclass.h"

static CSemaphoreClass g_tSemaphore;
static CString g_strLogFile;

CString CLog::GetModuleFullPath( void )
{
	TCHAR achDllName[32768] = _T("");
	CString csPath = _T("");

	//AfxGetInstanceHandle()可能获取失败
	// 	GetModuleFileName( AfxGetInstanceHandle(), achDllName, MAX_PATH);

	MEMORY_BASIC_INFORMATION mbi;   
	static int dummy; 
	UINT dwLength = sizeof(mbi); 
	if ( dwLength == VirtualQuery( &dummy, &mbi, dwLength ) )
	{
		GetModuleFileName( reinterpret_cast<HMODULE>(mbi.AllocationBase), achDllName, _countof(achDllName) ); 
		size_t nBuffLen = GetLongPathName( achDllName, 0, 0 );
		if ( nBuffLen == _tcslen( achDllName ) )
		{
			csPath = achDllName;
		}
		else
		{
			TCHAR* pChar = new TCHAR[nBuffLen + 1];
			ZeroMemory( pChar, sizeof(TCHAR) * ( nBuffLen + 1 ) );
			GetLongPathName( achDllName, pChar, nBuffLen );
			csPath = pChar;
			delete[] pChar;
		}		
	}

	csPath = csPath.Left( csPath.ReverseFind(_T('\\')) + 1 );

	return csPath;
}

void CLog::WriteLog( const char *pTemp )
{
	if (g_strLogFile.IsEmpty())
	{
		CString strPath = GetModuleFullPath();
		CString strLogDir = strPath + LOG_DIR;


		if(!PathFileExists(strLogDir))
		{
			CreateDirectory(strLogDir, NULL);
		}


		g_strLogFile = strLogDir + LOG_FILE;
	}

	CAutoLock cAuto(&g_tSemaphore);
	CFile cfile;

	//打开
	if (!PathFileExists(g_strLogFile))
	{
		BOOL bFlag = cfile.Open(g_strLogFile, CFile::modeCreate | CFile::modeWrite);
		if (!bFlag)
		{
			return;
		}
	}
	else
	{
		CFileStatus fileStaus;
		if (CFile::GetStatus(g_strLogFile, fileStaus))  
		{  
			UINT nOpenFlag = 0;
			if (fileStaus.m_size > LOG_SIZE)
			{
				nOpenFlag = CFile::modeCreate | CFile::modeWrite;
			}
			else
			{
				nOpenFlag = CFile::modeCreate | CFile::modeWrite | CFile::modeNoTruncate;
			}
			
			BOOL bFlag = cfile.Open(g_strLogFile, nOpenFlag);
			if (!bFlag)
			{
				return;
			}
		}  
	}

	//
	if (cfile.m_hFile != CFile::hFileNull)
	{
		cfile.SeekToEnd();
		cfile.Write(pTemp, strlen(pTemp)+1);
		cfile.Close();
	}
}

3.调用

	for (int i=0;i<100;i++)
	{
		LOG( "开始运行\r\n" );
	}