Re: [PATCH] stdlib: support non-GCC __attribute__

[Bruno Haible]

Paul Eggert wrote:
> If this seems OK, we can install similar workarounds for other
> misuses of __attribute__ in Gnulib now.

Yes, I agree gnulib should not interfere with the definition of
__attribute__ that the application has provided in its .h files.
Here's a proposed patch. I think the definitions of __attributes__ in
.c files have a low risk and can be left alone.


2011-02-13  Bruno Haible  <address@hidden>

        Don't interfere with a program's definition of __attribute__.
        * lib/argp.h (__attribute__): Remove definition.
        (_GL_ATTRIBUTE_FORMAT): New macro.
        (argp_error, __argp_error, argp_failure, __argp_failure): Use it.
        * lib/argp-fmtstream.h (__attribute__): Remove definition.
        (_GL_ATTRIBUTE_FORMAT): New macro.
        (__argp_fmtstream_printf, argp_fmtstream_printf): Use it.
        * lib/argp-help.c (hol_entry_long_iterate): Use __attribute__ only for
        GCC 3 or newer.
        * lib/error.h (__attribute__): Remove definition.
        (_GL_ATTRIBUTE_FORMAT): New macro.
        (error, error_at_line): Use it.
        * lib/hash.h (__attribute__): Remove definition.
        (ATTRIBUTE_WUR): Update definition.
        * lib/openat.h (__attribute__): Remove definition.
        (ATTRIBUTE_NORETURN): Update definition.
        * lib/sigpipe-die.h (__attribute__): Remove definition.
        (ATTRIBUTE_NORETURN): Update definition.
        * lib/vasnprintf.h (__attribute__): Remove definition.
        (_GL_ATTRIBUTE_FORMAT): New macro.
        (asnprintf, vasnprintf): Use it.
        * lib/xalloc.h (__attribute__): Remove definition.
        (ATTRIBUTE_NORETURN): Update definition.
        * lib/xmemdup0.h (__attribute__): Remove definition.
        (ATTRIBUTE_NORETURN): Update definition.
        * lib/xprintf.h (__attribute__): Remove definition.
        (_GL_ATTRIBUTE_FORMAT): New macro.
        (xprintf, xvprintf, xfprintf, xvfprintf): Use it.
        * lib/xstrtol.h (__attribute__): Remove definition.
        (ATTRIBUTE_NORETURN): Update definition.
        * lib/xvasprintf.h (__attribute__): Remove definition.
        (_GL_ATTRIBUTE_FORMAT): New macro.
        (xasprintf, xvasprintf): Use it.

--- lib/argp-fmtstream.h.orig   Sun Feb 13 12:34:37 2011
+++ lib/argp-fmtstream.h        Sun Feb 13 12:24:07 2011
@@ -28,15 +28,17 @@
 #include <string.h>
 #include <unistd.h>
 
-#ifndef __attribute__
 /* 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 __attribute__ only if these are supported too, because
+   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 __attribute__(Spec)   /* empty */
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 # endif
 #endif
 
@@ -128,10 +130,10 @@
 
 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));
 
 #if _LIBC || !defined __OPTIMIZE__
 extern int __argp_fmtstream_putc (argp_fmtstream_t __fs, int __ch);
--- lib/argp-help.c.orig        Sun Feb 13 12:34:37 2011
+++ lib/argp-help.c     Sun Feb 13 12:19:32 2011
@@ -570,7 +570,9 @@
 }
 
 static inline int
+#if __GNUC__ >= 3
 __attribute__ ((always_inline))
+#endif
 hol_entry_long_iterate (const struct hol_entry *entry,
                         int (*func)(const struct argp_option *opt,
                                     const struct argp_option *real,
--- lib/argp.h.orig     Sun Feb 13 12:34:37 2011
+++ lib/argp.h  Sun Feb 13 12:23:52 2011
@@ -34,15 +34,17 @@
 # define __NTH(fct) fct __THROW
 #endif
 
-#ifndef __attribute__
 /* 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 __attribute__ only if these are supported too, because
+   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 __attribute__(Spec)   /* empty */
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 # endif
 #endif
 
@@ -530,10 +532,10 @@
    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
@@ -546,11 +548,11 @@
 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));
 
 #if _LIBC || !defined __USE_EXTERN_INLINES
 /* Returns true if the option OPT is a valid short option.  */
--- lib/error.h.orig    Sun Feb 13 12:34:37 2011
+++ lib/error.h Sun Feb 13 12:24:19 2011
@@ -19,15 +19,17 @@
 #ifndef _ERROR_H
 #define _ERROR_H 1
 
-#ifndef __attribute__
 /* 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 __attribute__ only if these are supported too, because
+   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 __attribute__(Spec)   /* empty */
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 # endif
 #endif
 
@@ -40,11 +42,11 @@
    If STATUS is nonzero, terminate the program with `exit (STATUS)'.  */
 
 extern void error (int __status, int __errnum, const char *__format, ...)
-     __attribute__ ((__format__ (__printf__, 3, 4)));
+     _GL_ATTRIBUTE_FORMAT ((__printf__, 3, 4));
 
 extern void error_at_line (int __status, int __errnum, const char *__fname,
                            unsigned int __lineno, const char *__format, ...)
-     __attribute__ ((__format__ (__printf__, 5, 6)));
+     _GL_ATTRIBUTE_FORMAT ((__printf__, 5, 6));
 
 /* If NULL, error will flush stdout, then print on stderr the program
    name, a colon and a space.  Otherwise, error will call this
--- lib/hash.h.orig     Sun Feb 13 12:34:37 2011
+++ lib/hash.h  Sun Feb 13 12:11:14 2011
@@ -27,15 +27,14 @@
 # include <stdio.h>
 # include <stdbool.h>
 
-/* The warn_unused_result attribute appeared first in gcc-3.4.0 */
-# ifndef __attribute__
-#  if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
-#   define __attribute__(x)
-#  endif
-# endif
-
+/* The __attribute__ feature is available in gcc versions 2.5 and later.
+   The warn_unused_result attribute appeared first in gcc-3.4.0.  */
 # ifndef ATTRIBUTE_WUR
-#  define ATTRIBUTE_WUR __attribute__ ((__warn_unused_result__))
+#  if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
+#   define ATTRIBUTE_WUR __attribute__ ((__warn_unused_result__))
+#  else
+#   define ATTRIBUTE_WUR /* empty */
+#  endif
 # endif
 
 typedef size_t (*Hash_hasher) (const void *, size_t);
--- lib/openat.h.orig   Sun Feb 13 12:34:37 2011
+++ lib/openat.h        Sun Feb 13 12:14:10 2011
@@ -27,14 +27,12 @@
 #include <unistd.h>
 #include <stdbool.h>
 
-#ifndef __attribute__
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
-#  define __attribute__(x) /* empty */
-# endif
-#endif
-
 #ifndef ATTRIBUTE_NORETURN
-# define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)
+#  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+# else
+#  define ATTRIBUTE_NORETURN /* empty */
+# endif
 #endif
 
 #if !HAVE_OPENAT
--- lib/sigpipe-die.h.orig      Sun Feb 13 12:34:37 2011
+++ lib/sigpipe-die.h   Sun Feb 13 12:06:40 2011
@@ -47,14 +47,12 @@
 #endif
 
 
-# ifndef __attribute__
-#  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
-#   define __attribute__(x)
-#  endif
-# endif
-
 # ifndef ATTRIBUTE_NORETURN
-#  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+#  if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)
+#   define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+#  else
+#   define ATTRIBUTE_NORETURN /* empty */
+#  endif
 # endif
 
 /* Emit an error message indicating a SIGPIPE signal, and terminate the
--- lib/vasnprintf.h.orig       Sun Feb 13 12:34:37 2011
+++ lib/vasnprintf.h    Sun Feb 13 12:23:26 2011
@@ -24,15 +24,17 @@
 /* Get size_t.  */
 #include <stddef.h>
 
-#ifndef __attribute__
 /* 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 __attribute__ only if these are supported too, because
+   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 __attribute__(Spec)   /* empty */
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 # endif
 #endif
 
@@ -69,9 +71,9 @@
 # define vasnprintf rpl_vasnprintf
 #endif
 extern char * asnprintf (char *resultbuf, size_t *lengthp, const char *format, 
...)
-       __attribute__ ((__format__ (__printf__, 3, 4)));
+       _GL_ATTRIBUTE_FORMAT ((__printf__, 3, 4));
 extern char * vasnprintf (char *resultbuf, size_t *lengthp, const char 
*format, va_list args)
-       __attribute__ ((__format__ (__printf__, 3, 0)));
+       _GL_ATTRIBUTE_FORMAT ((__printf__, 3, 0));
 
 #ifdef __cplusplus
 }
--- lib/xalloc.h.orig   Sun Feb 13 12:34:37 2011
+++ lib/xalloc.h        Sun Feb 13 12:12:07 2011
@@ -26,14 +26,12 @@
 # endif
 
 
-# ifndef __attribute__
-#  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
-#   define __attribute__(x)
-#  endif
-# endif
-
 # ifndef ATTRIBUTE_NORETURN
-#  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+#  if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)
+#   define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+#  else
+#   define ATTRIBUTE_NORETURN /* empty */
+#  endif
 # endif
 
 # ifndef ATTRIBUTE_MALLOC
--- lib/xmemdup0.h.orig Sun Feb 13 12:34:37 2011
+++ lib/xmemdup0.h      Sun Feb 13 12:09:26 2011
@@ -25,14 +25,12 @@
 extern "C" {
 # endif
 
-# ifndef __attribute__
-#  if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
-#   define __attribute__(x)
-#  endif
-# endif
-
 # ifndef ATTRIBUTE_NORETURN
-#  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+#  if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)
+#   define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+#  else
+#   define ATTRIBUTE_NORETURN /* empty */
+#  endif
 # endif
 
 /* This function is always triggered when memory is exhausted.
--- lib/xprintf.h.orig  Sun Feb 13 12:34:37 2011
+++ lib/xprintf.h       Sun Feb 13 12:23:04 2011
@@ -20,26 +20,28 @@
 #include <stdarg.h>
 #include <stdio.h>
 
-#ifndef __attribute__
 /* 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 __attribute__ only if these are supported too, because
+   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 __attribute__(Spec)   /* empty */
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 # endif
 #endif
 
 extern int xprintf (char const *restrict format, ...)
-  __attribute__ ((__format__ (__printf__, 1, 2)));
+  _GL_ATTRIBUTE_FORMAT ((__printf__, 1, 2));
 extern int xvprintf (char const *restrict format, va_list args)
-  __attribute__ ((__format__ (__printf__, 1, 0)));
+  _GL_ATTRIBUTE_FORMAT ((__printf__, 1, 0));
 extern int xfprintf (FILE *restrict stream, char const *restrict format, ...)
-  __attribute__ ((__format__ (__printf__, 2, 3)));
+  _GL_ATTRIBUTE_FORMAT ((__printf__, 2, 3));
 extern int xvfprintf (FILE *restrict stream, char const *restrict format,
                       va_list args)
-  __attribute__ ((__format__ (__printf__, 2, 0)));
+  _GL_ATTRIBUTE_FORMAT ((__printf__, 2, 0));
 
 #endif
--- lib/xstrtol.h.orig  Sun Feb 13 12:34:37 2011
+++ lib/xstrtol.h       Sun Feb 13 12:07:17 2011
@@ -51,14 +51,12 @@
 _DECLARE_XSTRTOL (xstrtoull, unsigned long long int)
 #endif
 
-#ifndef __attribute__
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
-#  define __attribute__(x)
-# endif
-#endif
-
 #ifndef ATTRIBUTE_NORETURN
-# define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)
+#  define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
+# else
+#  define ATTRIBUTE_NORETURN /* empty */
+# endif
 #endif
 
 /* Report an error for an invalid integer in an option argument.
--- lib/xvasprintf.h.orig       Sun Feb 13 12:34:37 2011
+++ lib/xvasprintf.h    Sun Feb 13 12:24:31 2011
@@ -20,15 +20,17 @@
 /* Get va_list.  */
 #include <stdarg.h>
 
-#ifndef __attribute__
 /* 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 __attribute__ only if these are supported too, because
+   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 __attribute__(Spec)   /* empty */
+#ifndef _GL_ATTRIBUTE_FORMAT
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+#  define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+# else
+#  define _GL_ATTRIBUTE_FORMAT(spec) /* empty */
 # endif
 #endif
 
@@ -44,9 +46,9 @@
      - [EILSEQ] error during conversion between wide and multibyte characters,
    return NULL.  */
 extern char *xasprintf (const char *format, ...)
-       __attribute__ ((__format__ (__printf__, 1, 2)));
+       _GL_ATTRIBUTE_FORMAT ((__printf__, 1, 2));
 extern char *xvasprintf (const char *format, va_list args)
-       __attribute__ ((__format__ (__printf__, 1, 0)));
+       _GL_ATTRIBUTE_FORMAT ((__printf__, 1, 0));
 
 #ifdef __cplusplus
 }

-- 
In memoriam Alexander Samoylovich 
<http://en.wikipedia.org/wiki/Alexander_Samoylovich>