How to stop EnumWindows running infinitely win32

Question

The code worked all along. Somehow I manage to get Visual C++ Express not hit the break point on the final return statement and it appeared to run for ever.

In the e

Answer 1

hmm, i don't get why it would. i ran it and it worked just fine. it displayed all of the windows i have and then stopped. enumWindows will stop when either the enumWindowsProc returns false (you have it coded to always return true) or when it runs out of top-level windows to enumerate. -don

Answer 2

From the documentation:

EnumWindows continues until the last top-level window is enumerated or the callback function returns FALSE.

To continue enumeration, the callback function must return TRUE; to stop enumeration, it must return FALSE.

Answer 3

EnumWindowsProc should never run infinitely.

It should run until:

• Your callback returns FALSE
• There are no more top level windows to enumerate

So I suspect it appears to be running infinitely for you because of memory corruption or a memory access violation.

Your printf should be using %s not %S.

BOOL CALLBACK EnumWindowsProc(HWND hWnd, long lParam) {
    TCHAR buff[255];

    if (IsWindowVisible(hWnd)) {
        GetWindowText(hWnd, (LPWSTR) buff, 254);
        printf("%s\n", buff);//<--- %s means use TCHAR* which is WCHAR* in your case
    }
    return TRUE;
}

Also you shouldn't need to be casting your buff as a LPWSTR. If your buff is somehow a CHAR buffer then you need to compile with the Unicode character set.

Answer 4

Your code works for me, once I removed the wide-character stuff and added #include <stdio.h> to get the printf() declaration. What output does it produce on your system?

The code that works for me is:

#include <windows.h>
#include <stdio.h>

BOOL CALLBACK EnumWindowsProc(HWND hWnd, LPARAM lParam) {
    char buff[255];

    if (IsWindowVisible(hWnd)) {
        GetWindowText(hWnd, (LPSTR) buff, 254);
        printf("%s\n", buff);
    }
    return TRUE;
}

int main() {
    EnumWindows(EnumWindowsProc, 0);
    return 0;
}