Path: utzoo!news-server.csri.toronto.edu!rutgers!att!cbfsb!cbnewsc!ladd
From: ladd@cbnewsc.att.com (david.ladd)
Newsgroups: comp.os.minix
Subject: Re: A patch to make gcc 1.39 work with Minix setjmp
Message-ID: <1991Mar12.225635.29426@cbnewsc.att.com>
Date: 12 Mar 91 22:56:35 GMT
References: <1991Mar10.223859.380@santra.uucp>
Organization: AT&T Bell Laboratories
Lines: 22

In article <1991Mar10.223859.380@santra.uucp> jkp@cs.HUT.FI (Jyrki Kuoppala) writes:
>As distributed, Minix (1.5.10 and I think also 1.3) setjmp library
>routine doesn't save the registers which are not allowed to be
>clobbered by the called function.  Generally, Unix saves all registers
>in setjmp.  In my opinion, both of these methods seem to be about as
>good, also there are some points to support the Minix style.
>
>However, the compiler must be aware of when setjmp is called and must
>generate code to save the registers which are not allowed to be

I quote from the gcc.info file:

`-traditional'
     Attempt to support some aspects of traditional C compilers.                          Specifically:

	....

        * All automatic variables not declared `register' are
          preserved by `longjmp'.  Ordinarily, GNU C follows ANSI C:
          automatic variables not declared `volatile' may be clobbered.              
To me, this suggests you either make everything volatile or use
gcc -traditional.  What's the big deal?