------- Comment #3 from joseph at codesourcery dot com 2007-03-07 18:04 -------
Subject: Re: -std=c89 doesn't warn about gcc's "?:" extension
On Wed, 7 Mar 2007, manu at gcc dot gnu dot org wrote:
> The documentation says that you should use -pedantic to warn about GCC
> extensions[*], so I am not sure whether this is valid. But honestly, from the
> description of "-std=", I would understand that GNU extensions are disabled
> when using -std=c89 or that pedantic does not warn for them when using
> -std=gnu89, but neither of those are true.
The key concept is that of base standard, as described in this passage
from invoke.texi:
Where the standard specified with @option{-std} represents a GNU
extended dialect of C, such as @samp{gnu89} or @samp{gnu99}, there is a
corresponding @dfn{base standard}, the version of ISO C on which the GNU
extended dialect is based. Warnings from @option{-pedantic} are given
where they are required by the base standard. (It would not make sense
for such warnings to be given only for features not in the specified GNU
C dialect, since by definition the GNU dialects of C include all
features the compiler supports with the given option, and there would be
nothing to warn about.)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28368
