Re: [PATCH][BZ #16907] Sync argp.h __attribute__ with gnulib.

[Ondřej Bílka]

On Tue, Jun 03, 2014 at 12:59:11PM +0200, Aurelien Jarno wrote:
> On Fri, May 23, 2014 at 07:34:57PM +0200, Ondřej Bílka wrote:
> > On Fri, May 23, 2014 at 07:53:11AM -0700, Paul Eggert wrote:
> > > Ondřej Bílka wrote:
> > > >CCing gnulib. Could this be backported also there or do you have
> > > >different solution?
> > > 
> > > We solved this problem in a different way years ago, using something
> > > like this:
> > > 
> > > #if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR >= 7)
> > > # define _GL_ATTRIBUTE_FORMAT(s) __attribute__ ((__format__ s))
> > > #else
> > > # define _GL_ATTRIBUTE_FORMAT(s)
> > > #endif
> > > 
> > > and then using _GL_ATTRIBUTE_FORMAT ((__printf__, 2, 3)) later,
> > > instead of __attribute__ ((__format__ (__printf__, 2, 3))).
> > > Presumably glibc could do something similar.  Glibc could use a
> > > different name; that's all right, gnulib will just switch to the
> > > name that glibc uses.
> > 
> > Ok, here is patch that does that with unchanged name (Does somebody have
> > better one?).
> > 
> > As I looked at header differences they are mostly minor, like using
> > `foo' instead "foo" in comments so it migth be worthwhile to sync them
> > up.
> > 
> > 
> >         * argp/argp-fmtstream.h (_GL_ATTRIBUTE_FORMAT): Define.
> >     (argp_error, argp_failure): Use _GL_ATTRIBUTE_FORMAT.
> >         * argp/argp.h (__argp_fmtstream_printf): Likewise.
> 
> Thanks for working on this issue. The patch looks fine to me, and I have
> just tested it, it fixes the original issue. Please also note that your
> patch doesn't apply cleanly, it seems there are some issue with the
> context.
> 
Yes, I created that by taking a diff and removing extra parts so that
change man typo. A fixed version is here.

diff --git a/argp/argp-fmtstream.h b/argp/argp-fmtstream.h
index 1ed2834..fc07d91 100644
--- a/argp/argp-fmtstream.h
+++ b/argp/argp-fmtstream.h
@@ -29,19 +29,16 @@
 #include <string.h>
 #include <unistd.h>
 
-#ifndef __attribute__
-/* This feature is available in gcc versions 2.5 and later.  */
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5) || \
-  defined __STRICT_ANSI__
-#  define __attribute__(Spec) /* empty */
-# endif
-/* The __-protected variants of `format' and `printf' attributes
-   are accepted by gcc versions 2.6.4 (effectively 2.7) and later.  */
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7) || \
-  defined __STRICT_ANSI__
-#  define __format__ format
-#  define __printf__ printf
-# endif
+/* The __attribute__ feature is available in gcc versions 2.5 and later.
+   The __-protected variants of the attributes 'format' and 'printf' are
+   accepted by gcc versions 2.6.4 (effectively 2.7) and later.
+   We enable _GL_ATTRIBUTE_FORMAT only if these are supported too, because
+   gnulib and libintl do '#define printf __printf__' when they override
+   the 'printf' function.  */
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+#else
+# define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 #endif
 
 #if defined (__GNU_LIBRARY__) && defined (HAVE_LINEWRAP_H)
@@ -132,10 +129,10 @@ extern void argp_fmtstream_free (argp_fmtstream_t __fs);
 
 extern ssize_t __argp_fmtstream_printf (argp_fmtstream_t __fs,
                                        const char *__fmt, ...)
-     __attribute__ ((__format__ (printf, 2, 3)));
+     _GL_ATTRIBUTE_FORMAT ((printf, 2, 3));
 extern ssize_t argp_fmtstream_printf (argp_fmtstream_t __fs,
                                      const char *__fmt, ...)
-     __attribute__ ((__format__ (printf, 2, 3)));
+     _GL_ATTRIBUTE_FORMAT ((printf, 2, 3));
 
 extern int __argp_fmtstream_putc (argp_fmtstream_t __fs, int __ch);
 extern int argp_fmtstream_putc (argp_fmtstream_t __fs, int __ch);
diff --git a/argp/argp.h b/argp/argp.h
index 0868228..6a1cc1b 100644
--- a/argp/argp.h
+++ b/argp/argp.h
@@ -35,19 +35,16 @@
 # define __NTH(fct) fct __THROW
 #endif
 
-#ifndef __attribute__
-/* This feature is available in gcc versions 2.5 and later.  */
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5) || \
-  defined __STRICT_ANSI__
-#  define __attribute__(Spec) /* empty */
-# endif
-/* The __-protected variants of `format' and `printf' attributes
-   are accepted by gcc versions 2.6.4 (effectively 2.7) and later.  */
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7) || \
-  defined __STRICT_ANSI__
-#  define __format__ format
-#  define __printf__ printf
-# endif
+/* The __attribute__ feature is available in gcc versions 2.5 and later.
+   The __-protected variants of the attributes 'format' and 'printf' are
+   accepted by gcc versions 2.6.4 (effectively 2.7) and later.
+   We enable _GL_ATTRIBUTE_FORMAT only if these are supported too, because
+   gnulib and libintl do '#define printf __printf__' when they override
+   the 'printf' function.  */
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+#else
+# define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 #endif
 
 /* GCC 2.95 and later have "__restrict"; C99 compilers have
@@ -505,10 +502,10 @@ extern void __argp_usage (const struct argp_state 
*__state);
    message, then exit (1).  */
 extern void argp_error (const struct argp_state *__restrict __state,
                        const char *__restrict __fmt, ...)
-     __attribute__ ((__format__ (__printf__, 2, 3)));
+     _GL_ATTRIBUTE_FORMAT ((__printf__, 2, 3));
 extern void __argp_error (const struct argp_state *__restrict __state,
                          const char *__restrict __fmt, ...)
-     __attribute__ ((__format__ (__printf__, 2, 3)));
+    _GL_ATTRIBUTE_FORMAT ((__printf__, 2, 3));
 
 /* Similar to the standard gnu error-reporting function error(), but will
    respect the ARGP_NO_EXIT and ARGP_NO_ERRS flags in STATE, and will print
@@ -521,11 +518,11 @@ extern void __argp_error (const struct argp_state 
*__restrict __state,
 extern void argp_failure (const struct argp_state *__restrict __state,
                          int __status, int __errnum,
                          const char *__restrict __fmt, ...)
-     __attribute__ ((__format__ (__printf__, 4, 5)));
+     _GL_ATTRIBUTE_FORMAT ((__printf__, 4, 5));
 extern void __argp_failure (const struct argp_state *__restrict __state,
                            int __status, int __errnum,
                            const char *__restrict __fmt, ...)
-     __attribute__ ((__format__ (__printf__, 4, 5)));
+     _GL_ATTRIBUTE_FORMAT ((__printf__, 4, 5));
 
 /* Returns true if the option OPT is a valid short option.  */
 extern int _option_is_short (const struct argp_option *__opt) __THROW;