view m4/usleep.m4 @ 15308:a3ba680ad389

strerror_r: fix OpenBSD behavior on 0 OpenBSD treats strerror_r(0,,) as a success, but with a message "Undefined error: 0"; while this is distinct from strerror_r(-1,,) returning "Unknown error: -1", it does not imply success. Meanwhile, if buf is short enough for ERANGE, then we can't use strstr to look for "Unknown" or "Undefined" in the resulting message, like we had been doing for strerror(). Fix this by shifting the burden - now the strerror-override code guarantees that 0 will have an override when needed. * lib/strerror-override.c (strerror_override): Also override 0 when needed. * lib/strerror-override.h (strerror_override): Likewise. * lib/strerror.c (strerror): Simplify, now that 0 override is done earlier. * lib/strerror_r.c (strerror_r): Likewise. * m4/strerror.m4 (gl_FUNC_STRERROR): Split detection of 0 behavior... (gl_FUNC_STRERROR_0): ...into new macro. * m4/strerror_r.m4 (gl_FUNC_STRERROR_R): Replace strerror_r if 0 is overridden. (gl_FUNC_STRERROR_R_WORKS): Avoid extra tests if 0 is broken. * modules/strerror-override (Files): Add strerror.m4. (configure.ac): Also provide override for 0 when needed. * doc/posix-functions/strerror.texi (strerror): Document this. * doc/posix-functions/perror.texi (perror): Likewise. Signed-off-by: Eric Blake <eblake@redhat.com>
author Eric Blake <eblake@redhat.com>
date Tue, 21 Jun 2011 08:50:51 -0600
parents 69ac4e993bf3
children 8250f2777afc
line wrap: on
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# usleep.m4 serial 2
dnl Copyright (C) 2009-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

dnl This macro intentionally does not check for select or nanosleep;
dnl both of those modules can require external libraries.
AC_DEFUN([gl_FUNC_USLEEP],
[
  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
  dnl usleep was required in POSIX 2001, but dropped as obsolete in
  dnl POSIX 2008; therefore, it is not always exposed in headers.
  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
  AC_CHECK_FUNCS_ONCE([usleep])
  AC_CHECK_TYPE([useconds_t], [],
    [AC_DEFINE([useconds_t], [unsigned int], [Define to an unsigned 32-bit
      type if <sys/types.h> lacks this type.])])
  if test $ac_cv_func_usleep = no; then
    HAVE_USLEEP=0
  else
    dnl POSIX allows implementations to reject arguments larger than
    dnl 999999, but GNU guarantees it will work.
    AC_CACHE_CHECK([whether usleep allows large arguments],
      [gl_cv_func_usleep_works],
      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <unistd.h>
]], [[return !!usleep (1000000);]])],
        [gl_cv_func_usleep_works=yes], [gl_cv_func_usleep_works=no],
        [gl_cv_func_usleep_works="guessing no"])])
    if test "$gl_cv_func_usleep_works" != yes; then
      REPLACE_USLEEP=1
    fi
  fi
])