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From: ted@grebyn.com (Ted Holden)
Newsgroups: comp.lang.c++
Subject: Petzold's Windows examples with Zortech 2.1
Message-ID: <1991Mar6.130447.16332@grebyn.com>
Date: 6 Mar 91 13:04:47 GMT
Organization: Grebyn Corporation
Lines: 48


 
 
 
 
   Maybe Walter Bright or someone could answer this;  the guys on the tech
line at Zortech couldn't.  In Petzold's book "Programming Windows",
which is pretty much the standard book on the topic, the standard
section of code for setting up a window class (at least in one case) reads:
 
 
     if (!hPrevInstance) 
          {
          zwndclass.style         = CS_HREDRAW | CS_VREDRAW ;
          zwndclass.lpfnWndProc   = WndProc ;
          zwndclass.cbClsExtra    = 0 ;
          zwndclass.cbWndExtra    = 0 ;
          zwndclass.hInstance     = hInstance ;
          zwndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
          zwndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
          zwndclass.hbrBackground = GetStockObject (WHITE_BRUSH) ;
          zwndclass.lpszMenuName  = NULL ;
          zwndclass.lpszClassName = szAppName ;
 
          RegisterClass (&zwndclass) ;
          }
 
and this won't compile under Zortech 2.1.  The function name WndProc
must be typecast to void, i.e. the 2'nd line
 
 
          zwndclass.lpfnWndProc   = WndProc ;
 
must be changed to
 
          zwndclass.lpfnWndProc   = (void *) WndProc ;
 
and then the whole thing works with Zortech 2.1.  Nothing in windows.h would
seem to suggest such a requirement.  What gives??
 
Ted Holden
HTE