At 05:44 AM 10/23/00, Horst von Brand wrote:
>David Relson <relson@osagesoftware.com> said:
>
>Not just a preprocessor change.
>...
>This is true for a correct compiler (ever seen a correct piece of
>software?) compiling strictly standard-conforming source. The kernel is
>_not_ standard-conforming, and many places are writen just like they are to
>trick the compiler into generating particular code, some places assume that
>undefined behaviour (i.e., a[i] = b[i++] and such) works in a certain way,
>that the compiler pads structures in a certain way, ...
>...
>Yes. The existing program is wrong in that it woprked by chance, not
>because it was written right.
Horst,
What you say is correct. Early comments on gcc-2.96 reflected preprocessor
changes which made it impossible to compile a kernel. Later comments,
particularly David Wragg's "struct itimerval" example, show that compiler
optimizations is broken.
My recollection is that the behavior of "a[i] = b[i++]" is well defined,
i.e. in the standard. However it's been years since I paid attention to
those details, so I may be wrong.
Anyhow, as we all know, gcc-2.96 is not ready for prime time.
David
--------------------------------------------------------
David Relson Osage Software Systems, Inc.
relson@osagesoftware.com 514 W. Keech Ave.
www.osagesoftware.com Ann Arbor, MI 48103
voice: 734.821.8800 fax: 734.821.8800
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