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Re: preprocessor/5899: -M disables -dM
- From: Andreas Schwab <schwab at suse dot de>
- To: neil at gcc dot gnu dot org
- Cc: gcc-bugs at gcc dot gnu dot org, gcc-prs at gcc dot gnu dot org, gcc-gnats at gcc dot gnu dot org
- Date: Sat, 09 Mar 2002 20:46:45 +0100
- Subject: Re: preprocessor/5899: -M disables -dM
- References: <20020309194058.18974.qmail@sources.redhat.com>
neil@gcc.gnu.org writes:
|> I'm not sure this behaviour is a good idea. The documentation in 3.0 for -dM begins "Instead of the normal output", and the documentation for -M begins "Instead of outputting the result of preprocessing, output a rule suitable for make". In other words, I think you're relying on undocumented behaviour that just happened to work.
IMHO neither -dM nor -M produce "normal output", so it would not
contradict the docs to output both.
|> What did 2.95 do? I believe it output both to the same place. I'm waiting for confirmation from Chris Demetriou that the semantics of 3.1 now match 2.95 for -M etc., which is a regression that was fixed, and is pending for 3.0.5. If the 3.0 behaviour is not a regression from 2.95 then I see no reason to preserve it, particularly if it was undocumented.
Both 2.95 and 3.0.4 behave as expected by glibc.
Andreas.
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Andreas Schwab, SuSE Labs, schwab@suse.de
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