[Bug libc/15312] New: SEEK_HOLE and SEEK_DATA not exported as expected

[Bug libc/15312] New: SEEK_HOLE and SEEK_DATA not exported as expected

[sourceware.org@jan-o-sch.net]

http://sourceware.org/bugzilla/show_bug.cgi?id=15312

             Bug #: 15312
           Summary: SEEK_HOLE and SEEK_DATA not exported as expected
           Product: glibc
           Version: 2.17
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: unassigned@sourceware.org
        ReportedBy: sourceware.org@jan-o-sch.net
                CC: drepper.fsp@gmail.com
    Classification: Unclassified


The man pages for lseek(2) state one should include <sys/types.h> and
<unistd.h>. Doing so does not export SEEK_HOLE and SEEK_DATA.

Freshly built from git version 2.17.90, top commit
28831a9a671b109e49d0a4ddce00a08d734bfc97.

The following dummy source should build but doesn't:

--
#include <sys/types.h>
#include <unistd.h>

void
main(void)
{
        lseek(0, 0, SEEK_DATA);
        lseek(0, 0, SEEK_HOLE);
}
--

Errors:
/tmp/test.c: In function 'main':
/tmp/test.c:7: error: 'SEEK_DATA' undeclared (first use in this function)
/tmp/test.c:7: error: (Each undeclared identifier is reported only once
/tmp/test.c:7: error: for each function it appears in.)
/tmp/test.c:8: error: 'SEEK_HOLE' undeclared (first use in this function)

Including <linux/fs.h> is a work-around, but that should really be included
internally.

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[Bug libc/15312] SEEK_HOLE and SEEK_DATA not exported as expected

[aj at suse dot de]

http://sourceware.org/bugzilla/show_bug.cgi?id=15312

Andreas Jaeger <aj at suse dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |aj at suse dot de,
                   |                            |mtk.manpages at gmail dot
                   |                            |com
         Resolution|                            |INVALID

--- Comment #1 from Andreas Jaeger <aj at suse dot de> 2013-03-27 14:50:43 UTC ---
Please report this to the man pages project, I've added the man pages
maintainer to this report as well.

For details on reporting man-pages bugs:
https://www.kernel.org/doc/man-pages/reporting_bugs.html

marking as INVALID since it's not a bug in glibc itself but in the man-pages.

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[Bug libc/15312] SEEK_HOLE and SEEK_DATA not exported as expected

[sourceware.org@jan-o-sch.net]

http://sourceware.org/bugzilla/show_bug.cgi?id=15312

--- Comment #2 from Jan Schmidt <sourceware.org@jan-o-sch.net> 2013-03-27 15:04:55 UTC ---
So you really want a user space app to include <linux/fs.h> directly!?

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[Bug libc/15312] SEEK_HOLE and SEEK_DATA not exported as expected

[aj at suse dot de]

http://sourceware.org/bugzilla/show_bug.cgi?id=15312

--- Comment #3 from Andreas Jaeger <aj at suse dot de> 2013-03-27 15:12:27 UTC ---
No, I want the man pages clear enough that you know to add a define for
_GNU_SOURCE.

Try the following
#define _GNU_SOURCE 1
#include <sys/types.h>
#include <unistd.h>

void
main(void)
{
        lseek(0, 0, SEEK_DATA);
        lseek(0, 0, SEEK_HOLE);
}

have a look at /usr/include/unistd.h and read the glibc info pages about
feature test macros to learn about _GNU_SOURCE.

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[Bug libc/15312] SEEK_HOLE and SEEK_DATA not exported as expected

[sourceware.org@jan-o-sch.net]

http://sourceware.org/bugzilla/show_bug.cgi?id=15312

--- Comment #4 from Jan Schmidt <sourceware.org@jan-o-sch.net> 2013-03-27 17:55:05 UTC ---
Ok, thanks.

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[Bug libc/15312] SEEK_HOLE and SEEK_DATA not exported as expected

[mtk.manpages at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15312

--- Comment #5 from Michael Kerrisk <mtk.manpages at gmail dot com> 2013-03-27 20:50:59 UTC ---
(In reply to comment #3)
> No, I want the man pages clear enough that you know to add a define for

Thanks, Andreas, for adding me. I've added this text to the lseek(2) page:

       The _GNU_SOURCE feature test macro must be defined in order  to
       obtain   the   definitions  of  SEEK_DATA  and  SEEK_HOLE  from
       <unistd.h>.

> have a look at /usr/include/unistd.h and read the glibc info pages about
> feature test macros to learn about _GNU_SOURCE.

Or, for even more detail:

http://man7.org/linux/man-pages/man7/feature_test_macros.7.html

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[Bug libc/15312] SEEK_HOLE and SEEK_DATA not exported as expected

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15312

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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