windows messages

[ninjarider]

would the following code be correct
wndproc ...
...
.elseif umsg==WM_KEYDOWN
  mov kd[wParam], 1
.elseif umsg==WM_KEYUP
  mov kd[wParam], 0
.endif

[Tedd]

The logic is okay.
The instructions are a little off though. But I assume it's meant to be just pseudo code :wink

[czDrillard]

Hi ninjarider,

Only thing I can add is don't forget to xor eax,eax and ret if your app  processes either one of these messages.

best regards,

czDrillard

[ninjarider]

when u clear eax does that tell widows that the message has been handled. or is that just good ethics

[roticv]

The former I believe.

[Mark Jones]

Be sure to look up WM_KEY* in the WIN32.HLP file. This will tell you all you need to know. :)

[QvasiModo]

when u clear eax does that tell widows that the message has been handled. or is that just good ethics

The first, for most if not all window messages.

[hutch--]

ninjarider,

When a windows message specifies "return 0" it literally means zero EAX then call a RET.

Code Select Expand


    xor eax, eax
    ret


Note that it is not normally required for message procesing but if you use a DlgProc, it requires that you clear EAX before the procedure ends. This is not the same as closing a DlgProc but if you don't clear EAX, you will get some strange display problems with a dialog.

You exit a normal WndProc with the return value from,

    invoke DefWindowProc,hWin,uMsg,wParam,lParam

What is happening is that when a message requires a return value of ZERO you exit the WndProc BEFORE the Default processing where if you do a normal exit, you pass the default return value back to the OS.