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Re: AC_PROG_CC_C99 macro description is too vague / ambiguous
From: |
Ralf Wildenhues |
Subject: |
Re: AC_PROG_CC_C99 macro description is too vague / ambiguous |
Date: |
Tue, 21 Apr 2009 23:04:14 +0200 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
* Vincent Lefevre wrote on Wed, Mar 25, 2009 at 12:39:51AM CET:
> The documentation of AC_PROG_CC_C99 is rather vague:
>
> -- Macro: AC_PROG_CC_C99
> If the C compiler is not in C99 mode by default, try to add an
> option to output variable `CC' to make it so.
[...]
> It is not clear whether GNU extensions are allowed or not. Even though
> one may think that it is natural to keep the GNU extensions, gcc has
> -std=c99 for strict ISO C99 (as opposed to gnu99 for the GNU dialect),
> so that one can easily mix up "C99 mode" above and "c99 language" from
> gcc. The macro description should avoid this possible confusion.
OK?
Thanks,
Ralf
Improve description of AC_PROG_CC_C89 and AC_PROG_CC_C99.
* doc/autoconf.texi (C Compiler): Document that AC_PROG_CC_C89
and AC_PROG_CC_C99 prefer extended over strict conformance modes.
Report by Vincent Lefevre.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index ea71eb4..15f4e41 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -6810,7 +6810,8 @@ set to accept Standard C; if not, the shell variable
If the C compiler is not in @acronym{ANSI} C89 (@acronym{ISO} C90) mode by
default, try to add an option to output variable @code{CC} to make it
so. This macro tries various options that select @acronym{ANSI} C89 on
-some system or another. It considers the compiler to be in
+some system or another, preferring extended functionality modes over
+strict conformance modes. It considers the compiler to be in
@acronym{ANSI} C89 mode if it handles function prototypes correctly.
After calling this macro you can check whether the C compiler has been
@@ -6824,7 +6825,8 @@ This macro is called automatically by @code{AC_PROG_CC}.
@acindex{PROG_CC_C99}
If the C compiler is not in C99 mode by default, try to add an
option to output variable @code{CC} to make it so. This macro tries
-various options that select C99 on some system or another. It
+various options that select C99 on some system or another, preferring
+extended functionality modes over strict conformance modes. It
considers the compiler to be in C99 mode if it handles @code{_Bool},
@code{//} comments, flexible array members, @code{inline}, signed and
unsigned @code{long long int}, mixed code and declarations, named