vc++防止多次运行

#include<windows.h>

#include<stdio.h>

int main(int argc,char *argv[])

{

HANDLE hMutex;

DWORD dwErr;

hMutex=CreateMutex(NULL,//无安全描述

FALSE,//没有所有者

       "HACK");//对象名

 if(hMutex==NULL)//hMutex为NULL标示创建失败

{

MessageBox(NULL,"CreateMutex error!",NULL,MB_OK);

}

else

{

dwErr=GetLastError();

if(dwErr==ERROR_ALREADY_EXISTS)//互斥对象已经存在

{

MessageBox(NULL,"Application has already running",NULL,MB_OK);

ExitProcess(0);

}

}

getchar();

return 0;

}