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From: davea@quasar.wpd.sgi.com (David B.Anderson)
Newsgroups: comp.sys.sgi
Subject: Re: Bug or feature of the level 2 C optimizer?
Message-ID: <91144@sgi.sgi.com>
Date: 14 Mar 91 16:56:34 GMT
References: <1991Mar14.014517.26603@jarvis.csri.toronto.edu>
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Reply-To: davea@quasar.UUCP (David B.Anderson)
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Organization: Silicon Graphics, Inc., Mountain View, CA
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In article <1991Mar14.014517.26603@jarvis.csri.toronto.edu> lansd@dgp.toronto.edu (Robert Lansdale) writes:
>
>	For the longest while I've have had problems with longjmp()'s
>and level 2 optimizations in my rendering system. If an error occured
>during the loading of a script file then the program would go into an
>endless loop re-reading the first line of the file. The problem was
>non-existent for the non-optimized version.

[stuff deleted ]
>	char	*user_script_file = "test.file";
[stuff deleted ]

For correct operation, modify this to:
   char	* volatile user_script_file = "test.file";

The extra assignment you found effective is not guaranteed to work.

See the ANSI C Rationale on longjmp for further information. Page 86.
Also see the longjmp man page.   

Regards,
[ David B. Anderson  Silicon Graphics  (415)335-1548  davea@sgi.com ]
[``What can go wrong?''                           --Calvin to Hobbes]