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* [Bug libc/12204] New: glibc does has no POSIX compliant strerror_r function
@ 2010-11-09 23:14 bruno at clisp dot org
  2010-11-09 23:20 ` [Bug libc/12204] " bruno at clisp dot org
                   ` (10 more replies)
  0 siblings, 11 replies; 12+ messages in thread
From: bruno at clisp dot org @ 2010-11-09 23:14 UTC (permalink / raw)
  To: glibc-bugs

http://sourceware.org/bugzilla/show_bug.cgi?id=12204

           Summary: glibc does has no POSIX compliant strerror_r function
           Product: glibc
           Version: 2.8
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper.fsp@gmail.com
        ReportedBy: bruno@clisp.org


glibc has two strerror_r functions, declared in <string.h> depending on
feature macros. But none of them is POSIX compliant.

The one which is in effect when _GNU_SOURCE=1 has the declaration
char *strerror_r (int, char *, size_t). It has a different return type
and therefore a different calling convention than the POSIX function.
Test case:
=================================================
#define _GNU_SOURCE 1
#include <string.h>
#include <stdio.h>

int main()
{
  char buf[100];
  char *s = strerror_r (-2, buf, sizeof (buf));
  printf ("result: %s\n", s);
  return 0;
}
=================================================

The one which is in effect when _GNU_SOURCE is undefined and
_POSIX_C_SOURCE=200112L has the declaration
int strerror_r (int, char *, size_t), which is POSIX compatible,
but it has a different return value convention in case of failure.
POSIX:2001 and POSIX:2008 say that in case of failure the strerror_r
function should return "an error number"; this is the same wording
as for pthread_create, pthread_mutex_lock, etc. However, the glibc
function returns -1 and sets errno to the error number instead.
Test case:
========================================================================
#define _POSIX_C_SOURCE 200112L
#include <string.h>
#include <errno.h>
#include <stdio.h>

int main()
{
  char buf[100] = "______";
  int r;

  r = strerror_r (-2, buf, sizeof (buf));
  if (r == 0)
    printf ("result: success %s\n", buf);
  else if (r > 0)
    printf ("result: failure %d %s\n", r, buf);
  else
    printf ("result: non-POSIX failure %d %d %s\n", r, errno, buf);

  r = strerror_r (EACCES, buf, 3);
  if (r == 0)
    printf ("result: success %s\n", buf);
  else if (r > 0)
    printf ("result: failure %d %s\n", r, buf);
  else
    printf ("result: non-POSIX failure %d %d %s\n", r, errno, buf);

  return 0;
}
==========================================================================
Expected result:
result: failure 22 ______
result: failure 34 ______

Actual result:
result: non-POSIX failure -1 22 ______
result: non-POSIX failure -1 34 ______

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^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2014-06-30  6:29 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-11-09 23:14 [Bug libc/12204] New: glibc does has no POSIX compliant strerror_r function bruno at clisp dot org
2010-11-09 23:20 ` [Bug libc/12204] " bruno at clisp dot org
2010-11-09 23:20 ` bruno at clisp dot org
2010-11-10  8:14 ` drepper.fsp at gmail dot com
2010-11-10  9:10 ` schwab@linux-m68k.org
2010-11-11  9:36 ` bruno at clisp dot org
2010-12-25 19:17 ` drepper.fsp at gmail dot com
2011-05-18 23:34 ` eblake at redhat dot com
2013-02-08 19:35 ` dank at kegel dot com
2014-02-16 18:28 ` jackie.rosen at hushmail dot com
2014-05-28 19:41 ` schwab at sourceware dot org
2014-06-30  6:29 ` fweimer at redhat dot com

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