VC prohibits the program from running multiple copies at the same time (to prevent repeated running)

/// // <Prevent repeated operations> //// //////////////////////////////////////// ///
Cstring lpszname = "proj test"; // window title
Handle hmutex = NULL;
Hmutex =: openmutex (mutex_all_access, true, lpszname );
If (hmutex)
{

Cwnd * pwnd = cwnd: findwindow (null, lpszname); // captain of the window of the target process
If (pwnd)
{
If (para [1] = "exit ")
Pwnd-> sendmessage (wm_mymessage_stop, null, null); // send a message to the old process
Else {
MessageBox (null, "you have started Program ! "," Prompt ", mb_iconinformation );
}
// MessageBox (null, "Find window", "prompt", mb_iconinformation );
} Else {
MessageBox (null, "you have started the program! "," Prompt ", mb_iconinformation );
}

Return false;
}
Hmutex =: createmutex (null, true, lpszname );
/// // Prevents repeated operations> /// //////////////////////////////////////// ////