Hi! I''ve just finished reading WGPFD and i am now going through the chapters and trying the examples myself. I''m converting these examples, on the fly, from C to delphi. Currently i cant get this code snipit to work. The problem is probable easy to fix but ... const ClassName : pchar = ''WINCLASS1''; AppName : pchar = ''My First Window''; var WndClass_ : WNDCLASSex; error,sizeof_error_msg, error_msg : pchar; begin WndClass_.cbSize := sizeof(WndClass_); WndClass_.style := CS_HREDRAW or CS_VREDRAW; wndclass_.lpfnWndProc := @DefWindowProc; wndclass_.cbClsExtra := 0; wndclass_.cbWndExtra := 0; wndclass_.hinstance:= HINSTANCE; wndclass_.hbrBackground := COLOR_WINDOW +1 ; wndclass_.lpszMenuName := nil; wndclass_.lpszClassName := ClassName; wndclass_.hIcon := LoadIcon(0,IDI_APPLICATION); wndclass_.hIconSm := LoadIcon(0,IDI_APPLICATION); wndclass_.hCursor := LoadCursor(0,IDC_ARROW); if registerclassex(WndClass_) = 0 then begin error := getlasterror; sizeof_error_msg := FormatMessage( // source and processing options FORMAT_MESSAGE_ALLOCATE_BUFFER or FORMAT_MESSAGE_FROM_SYSTEM, nil, // pointer to message source error, // requested message identifier 0, // language identifier for requested message error_msg, // pointer to message buffer 0, // maximum size of message buffer nil); // pointer to array of message inserts ... The error returned by getlast error has the value of 2 Also the formatmessage doesnt work. How would i fix this? Ps can you give me an example of how to free the memory allocated in the FormatMessagea proc ? Or is that needed? Thanxs for any help provided.

I''m not sure, exactly, but here is how I would do it:

const
ClassName : string = ''WINCLASS1'';
AppName : string = ''My First Window'';
...
wndclass_.lpszClassName := PChar(ClassName);

You will probably want to make sure your definition of WNDCLASSex includes the "packed" directive:

type
WNDCLASSex=packed record
...
end;

Hope this helps. Without seeing the full converted file, it''s hard to be more specific.



DavidRM
Samu Games

I found out what was wrong.
It was the STUPID if!!!!
Delphi5 cant handle an winapi call in the evaluation section of an if statment!!!!!!!!
Here is a chunk of code which will not work :
if registerclass(wndclass_) = 0 then
begin
messagebox(0,''Critical Error : Unable to register Window Class'',''WinTetris'',mb_ok);
...

Here is the working version
tempresult := registerclass(wndclass_);
if tempresult = 0 then
begin
messagebox(0,''Critical Error : Unable to register Window Class'',''WinTetris'',mb_ok);
...
Talk about a STUPID bug.