Path: utzoo!utgpu!water!watmath!clyde!rutgers!cmcl2!brl-adm!umd5!purdue!gatech!mcnc!rti!sas!toebes
From: toebes@sas.UUCP (John Toebes)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga programmer's hint $14
Summary: It is only a problem for Manx - Lattice checks for the error.
Message-ID: <340@sas.UUCP>
Date: 19 Feb 88 14:46:39 GMT
References: <4230019@hpfclq.HP.COM>
Organization: SAS Institute Inc.,Cary NC,25712
Lines: 37

In article <4230019@hpfclq.HP.COM>, cunniff@hpfclq.HP.COM (Ross Cunniff) writes:
> For those of you who are using the Manx compiler (and perhaps for
> those of you using 16-bit ints with the Lattice compiler), here's
> a tip to help you avoid the Guru on machines with more that 512K.
> This really happened to a friend of mine (we spent an entire WEEKEND
> sorting this out; I would've seen it sooner, but Lattice promotes
> bad programming practices :-< ).
> 	Q. What's wrong with this program?
> 	   #include <intuition/intuition.h>
> 	   struct IntuitionBase *IntuitionBase;
> 	   main()
> 	   {
> 	       IntuitionBase = (struct IntuitionBase *)
> 				OpenLibrary( "intuition.library", 33L );
> 	       JRandomIntuitionCall( .... );
> 	   }
> 	A. OpenLibrary is not declared explicitly as returning a
> 	   pointer.
Under 4.0 (which supports short integers) the compiler will complain with
error 101 whenever you do this.  I have seen too many people get bit by
this on the PC to let it happen on the Amiga with Lattice.  The basic
rule is that if you ever convert a 16 bit entity to a pointer *REGARDLESS
OF ANY CAST* it will issue the error message.  This will catch almost
all of the errors of this type (only one it can't is if you do it through
indirect pointers in a called subroutine or in assembler - but then again
it isn't apparent from the source code anyway).

There is also a compiler switch -cf that will have the compiler scream
if you ever call anything for which there is no prototype.  Personnaly,
I always compile with the switch and demand that the compile proceed
without warnings, but I like the compiler to find my errors instead of having
to wait for the GURU to find them :-)

/*---------------------All standard Disclaimers apply---------------------*/
/*----Working for but not officially representing SAS or Lattice Inc.-----*/
/*----John A. Toebes, VIII             usenet:...!mcnc!rti!sas!toebes-----*/
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