程序只允許運行一次

 
#include<windows.h>
#include<stdio.h>
int main(int argc,char *argv[])
{
HANDLE hMutex;
DWORD dwErr;
hMutex=CreateMutex(NULL,//無安全描述
FALSE,//沒有所有者
       "HACK");//對象名
 if(hMutex==NULL)//hMutex爲NULL標示創建失敗
{
MessageBox(NULL,"CreateMutex error!",NULL,MB_OK);
}
else
{
dwErr=GetLastError();
if(dwErr==ERROR_ALREADY_EXISTS)//互斥對象已經存在
{
MessageBox(NULL,"Application has already running",NULL,MB_OK);
ExitProcess(0);
}

}
getchar();
return 0;
}