C winapi hwnd returning null - c

Question

I have tried everything to find the problem, but down below is my code and hwnd returns NULL when I run the program. What might be the reasons? The code seems fine. The program was working fine for a long while until 15 mins ago. I cut this part of the source code and ran it again but it still return NULL. This is that part that I cut.
#include <windows.h>
#define IDI_MYICON 103
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam){
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
//font
/*hFont = CreateFont(40,0,0,0,700,FALSE,FALSE,FALSE,DEFAULT_CHARSET,OUT_OUTLINE_PRECIS, CLIP_DEFAULT_PRECIS,ANTIALIASED_QUALITY, VARIABLE_PITCH,TEXT("a"));
hFontIpAdres = CreateFont(25,0,0,0,700,FALSE,FALSE,FALSE,DEFAULT_CHARSET,OUT_OUTLINE_PRECIS, CLIP_DEFAULT_PRECIS,ANTIALIASED_QUALITY, VARIABLE_PITCH,TEXT("a"));
hFontKurbanSecimi = CreateFont(30,0,0,0,700,FALSE,FALSE,FALSE,DEFAULT_CHARSET,OUT_OUTLINE_PRECIS, CLIP_DEFAULT_PRECIS,ANTIALIASED_QUALITY, VARIABLE_PITCH,TEXT("a"));
*/
WNDCLASSEX wc;
HWND hwnd;
MSG msg;
char *windowClassName = "class1";
printf("%s\n", windowClassName);
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON));
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;//MAKEINTRESOURCE(IDR_MYMENU);
wc.lpszClassName = windowClassName;
wc.hIconSm = NULL;//(HICON)LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON), IMAGE_ICON, 16, 16, 0);
if(!RegisterClassEx(&wc))
{
printf("window registration failed\n");
}
printf("%s\n", windowClassName);
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE, windowClassName,"TTr",WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL, hInstance, NULL
);
if(hwnd == NULL){
printf("could not create window hwnd %d\n", GetLastError());
}
ShowWindow(hwnd, SW_SHOW);
UpdateWindow(hwnd);
while(GetMessage(&msg, NULL, 0, 0) > 0){
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}

Answer 1

Your WndProc() function doesn't return anything. CreateWindowEx() will actually call the window proc with some creation-based messages.
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
return DefWindowProc(hwnd, msg, wParam, lParam);
}