Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU
Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!CORY.BERKELEY.EDU!dillon
From: dillon@CORY.BERKELEY.EDU (Matt Dillon)
Newsgroups: net.micro.amiga
Subject: Problems with compiling using 16-bit ints (MANX C)
Message-ID: <8605102156.AA03379@cory>
Date: Sat, 10-May-86 17:56:55 EDT
Article-I.D.: cory.8605102156.AA03379
Posted: Sat May 10 17:56:55 1986
Date-Received: Tue, 13-May-86 00:38:42 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: University of California at Berkeley
Lines: 40


	The most common problem is really not the compiler's fault.  Many
of you all assume integers are the same size as pointers, and do things like:

	win = (struct Window *)OpenWindow() ...

	This is incorrect.  If the compiler uses 16-bit integers, and since
OpenWindow() returns an integer, you will loose the MSB word of the
returned value when it is converted to a pointer.  The proper way to do
the call is:

	extern struct Window *OpenWindow();

	win = OpenWindow();


	If the library or system call can return different types of pointers,
then you should still extern it to SOME type of pointer:

	extern char *OpenLibrary();
	struct GfxBase GfxBase;
	struct MathBase MathBase;

	GfxBase = (struct GfxBase *)OpenLibrary( ...)
	MathBase= (struct MathBase *)OpenLibrary( ...)


	If you will never use the returned pointer (but still must set it
for the library routines to use), then it would suffice to just declare
everything as char *:

	extern char *OpenLibrary();
	char *GfxBase, *MathBase;

	GfxBase = OpenLibrary( ...)
	MathBase= OpenLibrary( ...)



					-Matt