Calling RasHangUp without errors.

Problem

The RasHangUp function terminates a remote access connection. The connection is specified with a RAS connection handle. The function releases all RASAPI32.DLL resources associated with the handle. (MSDN)

Then, in remarks, it is mentioned that the application should sleep about 3 seconds, or until RasGetConnectStatus returns ERROR_INVALID_HANDLE. If you realy just call RasHangUp and exit you can "hang" both the modem and rnaapp (the application that implements Dial-Up Services). Furthermore, if you do everything as described in MSDN you may still receive the following error message:

RNAAPP caused an invalid page fault in module xxxx.

Solution

This problem was a besetting sin when I wrote my Dial-up dialer program, until I found a solution that works in my program:

DWORD dwRet;
RASCONNSTATUS rStatus;
ZeroMemory(&rStatus, sizeof(RASCONNSTATUS));
rStatus.dwSize = sizeof(RASCONNSTATUS);
dwRet = RasGetConnectStatus(hRasConn, &rStatus);
if (dwRet != ERROR_INVALID_HANDLE)
{
	RasHangUp(hRasConn);  // hRasConn - valid handle to the RAS connection
	MSG msg;
	while (dwRet != ERROR_INVALID_HANDLE)
	{
		while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
		{
	   		TranslateMessage(&msg);
		   	DispatchMessage(&msg);
		}
		dwRet = RasGetConnectStatus(hRasConn, &rStatus);
	}
}

Note: I removed some unimportant stuff so check this code before using...