C++ Win 32 API: Problem With Passing window SW_HIDE - c++

Question

I am attempting to hide a 3rd part window on bootup of our computers. I am using the following code.
#include<windows.h>
#include <stdio.h>
int main() {
char windowName[500];
HWND window = FindWindow("WindowClassAsReportedByWindowSpy++", NULL);
//GetWindowText(window, windowName, 63);
ShowWindow(firefox,SW_HIDE);
getchar();
return 0;
}
The only problem is the window will not hide. Any ideas on why this isn't working /how I could accomplish this differently.

Answer 1

Most likely your program calls FindWindow before the target window is created, and so doesn't find it.
You'll need to sleep and retry the find.

Answer 2

You probably want to do sanity checks to make sure FindWindow is not returning NULL. Even better, call FindWindow in a loop until it doesn't return NULL.
#include <windows.h>
#include <stdio.h>
static const wchar_t g_cszFirefoxClass[] = L"firefox";
int __cdecl wmain(__in int argc, __in_ecount_z_opt(argc) wchar_t* _wargv[], __in_z_opt __wenviron[])
{
UNREFERENCED_PARAMETER(argc);
UNREFERENCED_PARAMETER(_wargv);
UNREFERENCED_PARAMETER(__wenviron);
HWND hWnd;
do {
hWnd = FindWindow(g_cszFirefoxClass, NULL);
Sleep(100);
} while (hWnd == NULL);
wprintf(L"[-] Firefox found! [HWND = 0x%X]\n", hWnd);
if (ShowWindow(hWnd, SW_HIDE))
{
wprintf(L"[-] Successfully hid Firefox window!\n");
return EXIT_SUCCESS;
}
else
{
fwprintf(stderr, L"[x] Failed to hide Firefox window..\n");
return EXIT_FAILURE;
}
}