Path: utzoo!attcan!uunet!lll-winken!ames!xanth!nic.MR.NET!umn-d-ub!uwvax!dogie!yahnke@vms.macc.wisc.edu
From: yahnke@vms.macc.wisc.edu (Ross Yahnke, MACC)
Newsgroups: comp.sys.mac.programmer
Subject: Re: serious code generation bug in Lightspeed C
Message-ID: <1112@dogie.edu>
Date: 18 Jan 89 14:10:40 GMT
Sender: news@dogie.edu
Organization: University of Wisconsin Academic Computing Center
Lines: 52

In article <6327@hoptoad.uucp>, tim@hoptoad.uucp (Tim Maroney) writes...

>In article <1532@cps3xx.UUCP> rang@cpswh.cps.msu.edu (Anton Rang) writes:
>>  Well, maybe not *well* documented, but documented at least.  From
>>Inside Mac, volume II, page 16:
>>
>>    The Lisa Pascal compiler frequently dereferences handles during
>>    its normal operation.....
> 
>Yes, but that starts with "The Lisa Pascal compiler".  There is nothing
>documented about this being a problem with C...
>Nor does THINK document it with reference to LSC...
>-- 
>Tim Maroney, Consultant, Eclectic Software, sun!hoptoad!tim

Tim, you are simply wrong, and obstinate to belabour the issue. As other 
people in this group have pointed out, the problem you've mentioned is
documented in Inside Mac. Yes, of course the examples are in Pascal. 
That was the only development language readily available when the Mac 
was brought out. I don't think it takes a PhD. to extrapolate the hows 
and whys of the problem from Pascal to C, the two languages are not that 
incredibly different. For you to say that "There is nothing documented 
about this being a problem with C" is a specious palaver, and also 
completely untrue.

In the latest set of documentation for LSC, the small set of double 
manuals with the Symantec label that was issued for the 2.0 release,
on Page 121 of the User's Manual:

  If you are dereferencing Handles, make sure that the memory the Handle 
  points won't move while using it. Otherwise, HLock it (and HUnlock it 
  later). Example:

    HLock(aTEH);
    /* Without the previous HLock,  */
    /* the next two calls may not always work */

    /* (1) printf calls Memory Mgr: */
    printf("first char in text handle is %c\n", **(**aTEH).hText);

    /* (2) Handle dereference on the left is done BEFORE call: */
    (**aTEH).hText = (Handle)NewHandle(somesize);

    HUnlock(aTEH);

So the problem *IS* well documented if only you bother to read the 
manual. You do *own* a copy of the manual, don't you?

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