Reputation: 2978
I've the following piece of code in my program which dynamically links wtsapi32.dll file for session notifications like WTS_SESSION_LOCK
and WTS_SESSION_UNLOCK
and runs in background. After the first lock/unlock the program hangs and not responding.
Is this a right way of doing explicit linking ?
void RegisterSession(HWND hwnd)
{
typedef DWORD (WINAPI *tWTSRegisterSessionNotification)( HWND,DWORD );
tWTSRegisterSessionNotification pWTSRegisterSessionNotification=0;
HINSTANCE handle = ::LoadLibrary("wtsapi32.dll");
pWTSRegisterSessionNotification = (tWTSRegisterSessionNotification) :: GetProcAddress(handle,"WTSRegisterSessionNotification");
if (pWTSRegisterSessionNotification)
{
pWTSRegisterSessionNotification(hwnd,NOTIFY_FOR_THIS_SESSION);
}
::FreeLibrary(handle);
handle = NULL;
}
Edited:
I have another method UnRegisterSession() function which calls WTSUnRegisterSessionNotification, I am calling the RegisterSession() in WinMain method ( removed FreeLibrary as suggested by 1800) and calling UnRegisterSession() in WM_DESTROY of CALLBACK WindowProcedure function. But still the application hangs.
Upvotes: 1
Views: 783
Reputation: 11441
According to the documentation (http://msdn.microsoft.com/en-us/library/aa383841(VS.85).aspx):
"When a window no longer requires these notifications, it must call WTSUnRegisterSessionNotification before being destroyed."
I would try unregistering the notification during WM___CLOSE instead of WM_DESTROY.
Upvotes: 0
Reputation: 7521
MS documentation suggests that you must call WTSUnRegisterSessionNotification before re-registering the session - as it only happens on your second attempt to lock it perhaps this is your issue?
With 1800 wrt the free library - you must keep this library loaded while you use it.
Upvotes: 0
Reputation: 135463
I'd say you probably cannot safely call FreeLibrary like that - you will be unloading the code you want to have call you. You should probably ensure not to free the dll until after you are finished getting notifications.
Upvotes: 4