Re: preprocessor/5806: The preprocessor evaluates expression s in 64-bit, violating IS C++ 16.1.4

[Neil Booth <neil@daikokuya.demon.co.uk>]

The following reply was made to PR preprocessor/5806; it has been noted by GNATS.

From: Neil Booth <neil@daikokuya.demon.co.uk>
To: Zack Weinberg <zack@codesourcery.com>
Cc: eric_dana@bmc.com, gcc-gnats@gcc.gnu.org, dick_schoeller@bmc.com
Subject: Re: preprocessor/5806: The preprocessor evaluates expression s in 64-bit, violating IS C++ 16.1.4
Date: Fri, 1 Mar 2002 23:13:14 +0000

 Zack Weinberg wrote:-
 
 > The preprocessor ought to do this only in C99 mode; in C++ and
 > presumably also C89 mode (I don't have a copy of C89 to check) it
 > should use long/unsigned long, which may be 32 bits wide on some
 > targets.  Unfortunately, doing this properly requires substantial
 > changes to GCC, which are planned, but not currently practical.
 > (We're already not quite compliant; preprocessor arithmetic uses the
 > _host's_ idea of intmax_t, not the target's.)
 > 
 > Neil - as a stopgap, it occurs to me that we could mask intermediate
 > values down to 32 bits when in C89/C++ mode and sizeof(target unsigned
 > long) == 4.  Thoughts?
 
 Sounds OK to me.  Like you, I have the C++ and C99 standards, but no C89
 lying around.  I do believe that the C++ preprocessor section was copied
 almost verbatim (with some changes for bool and true / false) from C89
 though.
 
 Neil.