Create OpenGL window win32 API - windows

Question

I am trying to create an OpenGL window inside of already existing parent window using win32 api. However, when creating a child, the function CreateWindowEx returns NULL with an error 1407 ERROR_CANNOT_FIND_WND_CLASS. The window must be a child so there is a space left for other controls such as buttons and checkboxes...
Part of code that creates the parent window:
WNDCLASSEX wincl;
wincl.style = 0;
wincl.lpszMenuName = NULL;
wincl.lpszClassName = L"WindowClass";
wincl.lpfnWndProc = WndProc;
wincl.hInstance = hInstance;
wincl.hIconSm = LoadIcon(NULL, IDC_ICON);
wincl.hIcon = LoadIcon(NULL, IDC_ICON);
wincl.hbrBackground = (HBRUSH)(COLOR_WINDOW);
wincl.cbWndExtra = 0;
wincl.cbSize = sizeof(WNDCLASSEX);
wincl.cbClsExtra = 0;
if(!RegisterClassEx(&wincl)){
std::cout << "Window failed to register!" << std::endl;
return false;
}
DWORD style = WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_SYSMENU | WS_SIZEBOX;
parentHwnd = CreateWindowEx(WS_EX_CLIENTEDGE,
L"WindowClass",
L"Title",
style,
CW_USEDEFAULT, // X
CW_USEDEFAULT, // Y
800, // Width
600, // Height
NULL,
NULL,
hInstance,
0);
if (parentHwnd == NULL){
std::cout << "Window failed to create!" << std::endl;
return false;
}
ShowWindow(parentHwnd, SW_SHOWNORMAL);
UpdateWindow(parentHwnd);
Inside the message loop, I am creating the child window:
LRESULT WndProc(HWND hwnd, UINT Msg, WPARAM wParam , LPARAM lParam){
switch (Msg){
case WM_CREATE:{
// Create child OpenGL window
childHwnd = CreateWindowEx(0,
L"OpenGL",
NULL,
WS_CLIPCHILDREN | WS_VISIBLE,
100, // X
100, // Y
400, // Width
300, // Height
hwnd, // Parent
0, // ID
NULL,
NULL);
// Prints 1407 ERROR_CANNOT_FIND_WND_CLASS
std::cout << "Last error: " << GetLastError() << std::endl;
}
default:{
return DefWindowProc(hwnd, Msg, wParam, lParam);
}
}
return 0;
}
I have looked into several tutorials (NeHe, cs.rit.edu, and many other but I can't post more than 2 links) and all of them used L"OpenGL" as class name for the second argument in the function CreateWindowEx().
What am I doing wrong? Is "OpenGL" a valid class name such as "Edit" / "Static" / "Button" ? Can I replace it with something else? I tried "Static" but it did not rendered anything.
I know there are many libraries (GLFW, SDL, ...) that handle window creation, but I need to use pure win32 API.
UPDATE:
RegisterClass() solved the problem. Here is the code that works for me:
WNDCLASS wc = {0};
wc.lpfnWndProc = WndProc;
wc.hInstance = hInstance; // Same hinstance used by parent
wc.hbrBackground = (HBRUSH)(COLOR_BACKGROUND);
wc.lpszClassName = L"OpenGL";
wc.style = CS_OWNDC;
if(!RegisterClass(&wc)){
std::cout << "Failed to register window!" << std::endl;
return false;
}
childHwnd = CreateWindowEx(0, // Must be zero
L"OpenGL",
NULL,
WS_VISIBLE | WS_CHILD,
100, // X
100, // Y
400, // Width
300, // Height
parentHwnd, // Parent HWND
0, // ID
hInstance, // Same hinstance used by parent
NULL);