[Bug c/53182] New: GNU C: attributes without underscores should be discouraged / no longer be documented e.g. as examples

[Bug c/53182] New: GNU C: attributes without underscores should be discouraged / no longer be documented e.g. as examples

[vincent-gcc at vinc17 dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53182

             Bug #: 53182
           Summary: GNU C: attributes without underscores should be
                    discouraged / no longer be documented e.g. as examples
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: vincent-gcc@vinc17.net


Attributes without underscores can conflict with the ISO C standard. For
instance, if the C11 <stdnoreturn.h> header is included, this breaks GCC's

  __attribute__ ((noreturn))

(such problems may occur in particular if different libraries, with different
expectations, are used). To avoid such a clash, only the __noreturn__ version
should be used. Other attributes without __ may also lead to conflicts with a
future C standard. You can see

  http://lists.gnu.org/archive/html/bug-gnulib/2012-05/msg00024.html

and the corresponding discussion, from which I've reported this bug.

I suggest the following changes:

* Fix the GCC manual: the versions without __ should be discouraged (explain
why) and the examples should always use the __ version, e.g. change

          void fatal () __attribute__ ((noreturn));

to

          void fatal () __attribute__ ((__noreturn__));

* Possibly issue a warning if an attribute without __ is used.

[Bug c/53182] GNU C: attributes without underscores should be discouraged / no longer be documented e.g. as examples

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53182

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |documentation
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-05-02
     Ever Confirmed|0                           |1
           Severity|normal                      |enhancement

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-05-02 11:54:02 UTC ---
Confirmed.

[Bug c/53182] GNU C: attributes without underscores should be discouraged / no longer be documented e.g. as examples

[ericb at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53182

Eric Blake <ericb at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ericb at gcc dot gnu.org

--- Comment #2 from Eric Blake <ericb at gcc dot gnu.org> 2012-05-02 13:27:28 UTC ---
It would also help to add an attribute named __attribute__((_Noreturn)) (and
therefore also adding __attribute__((___Noreturn__)), of course), for this
particular instance of <stdnoreturn.h> vs. existing code.