AfxRegisterWndClass crashes when called again

etechX2

Hi, In my MFC project, I get crash as follows: 1. i call MyCreate() then MyUnCreate() 2. calling MyCreate() the second time, causes crash at AfxRegisterWndClass below. sudo code provided: CMyCwndSub is derived from CWnd. in another file: CMyCwndSub *p;

void MyCreate()
{
//in here code looks for Window with title "MyWndWin".

p->new CMyCwndSub;
CString m = **AfxRegisterWndClass**(0);       //crashes in this line the 2nd time called.
p->CreateEx(0, m, -T"MyWndWin",0,0,0,0,0,NULL,0);

.
.
.

}

void MyUnCreate()
{
delete p;
p = NULL;
}

Victor Nijegorodov

Try to [UnregisterClassA function (winuser.h) - Win32 apps | Microsoft Learn](https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-unregisterclassa) in the MyUnCreate()

etechX2

would this work?.

//inside mfc library
void MyUnCreate()
{
::UnregisterClass(_T("MyWndWin"), AfxGetInstanceHndle());
delete p;
p = NULL;
}

Victor Nijegorodov

Didn't you test it? :confused: Also you must pass to UnregisterClass the className returned by AfxRegisterWndClass(...), not the caption of your window!

etechX2

I did the following and still crashed. Maybe the AfxRegisterWndClass is set to release class automatically at the end when library exits. ?

//inside mfc library
void MyUnCreate()
{
::UnregisterClass(ClassName, AfxGetInstanceHandle());
delete p;
p = NULL;
}

Victor Nijegorodov

etechX2 wrote:

Maybe the AfxRegisterWndClass is set to release class automatically at the end when library exits. ?

1. Please read the Microsoft documentation about AfxRegisterWndClass; 2. Why are you trying to unregister and then reregister already registered Class? just save its name and then use it again!