x86 assembly - window does not show up yet no compile-time errors - windows

Question

I am trying to create a window in x86 assembly with masm32 using the CreateWindowEx API. I have gotten my code to have no compile-time errors or anything of the sort- it compiles just fine. Yet when I run the exe, nothing happens. I don't see any obvious errors, and I have practically copied the code out of Iczelion's Win32 Tutorial (Part 3 - A Simple Window). What is wrong with it?
Here is my code:
.386
.model flat, stdcall
option casemap :none
WinMain proto :DWORD,:DWORD, :DWORD,:DWORD
include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\gdi32.inc
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\gdi32.lib
.data
ClassName db "Testwin", 0
AppName db "Testing Window", 0
.data?
hInstance HINSTANCE ?
CommandLine LPSTR ?
.code
start:
push NULL
call GetModuleHandle
mov hInstance,eax
call GetCommandLine
mov CommandLine, eax
push SW_SHOWDEFAULT
push CommandLine
push NULL
push hInstance
call WinMain
push eax
call ExitProcess
WinMain proc hInst:HINSTANCE,hPrevInst:HINSTANCE, CmdLine:LPSTR,CmdShow:DWORD
; local vars:
LOCAL wc:WNDCLASSEX
LOCAL msg:MSG
LOCAL hwnd:HWND
; defining the window:
mov wc.cbSize,SIZEOF WNDCLASSEX
mov wc.style, CS_HREDRAW or CS_VREDRAW
mov wc.lpfnWndProc, OFFSET WndProc
mov wc.cbClsExtra,NULL
mov wc.cbWndExtra,NULL
push hInst
pop wc.hInstance
mov wc.hbrBackground,COLOR_WINDOW+1
mov wc.lpszMenuName,NULL
mov wc.lpszClassName,OFFSET ClassName
invoke LoadIcon,NULL,IDI_APPLICATION
mov wc.hIcon,eax
mov wc.hIconSm,eax
invoke LoadCursor,NULL,IDC_ARROW
mov wc.hCursor,eax
invoke RegisterClassEx, addr wc
;create the window
invoke CreateWindowEx,NULL,ADDR ClassName,ADDR AppName,\
WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,\
CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,\
hInst,NULL
invoke ShowWindow,hwnd,SW_SHOWNORMAL
WinMain endp
WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM
cmp uMsg, WM_DESTROY
jne _next
invoke PostQuitMessage, NULL
_next:
WndProc endp
end start
Where have I gone wrong? I suspect it has something to do with CreateWindowEx, considering it takes 12 parameters, most of which I don't understand.
Thanks in advance.

Answer 1

I believe you have not assigned the window handle returned by CreateWindowEx to the hwnd variable.
So add the following line after invoke CreateWindowEx and before invoke ShowWindow -
mov hwnd, eax

Answer 2

We do not compile anything when using Assebmly! We Assemble and Link.
This is not C or any other high level language, you do not need WinMain.
The biggie, where is your message loop
After your CreateWindowEx and ShowWindow, you need something like this right after that:
.while TRUE
invoke GetMessage,addr msg,NULL,0,0
.break .if !eax
;invoke IsDialogMessage,hModelessDialog,addr msg
;.if !eax
;invoke TranslateAccelerator,hWnd,hAccel,addr msg
;.if !eax
invoke TranslateMessage,addr msg
invoke DispatchMessage,addr msg
;.endif
;.endif
.endw
You are also missing ret at the end of your procs