m4/fstatat.m4

   1 # fstatat.m4 serial 3
   2 dnl Copyright (C) 2004-2014 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 # Written by Jim Meyering.
   8
   9 # If we have the fstatat function, and it has the bug (in AIX 7.1)
  10 # that it does not fill in st_size correctly, use the replacement function.
  11 AC_DEFUN([gl_FUNC_FSTATAT],
  12 [
  13   AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
  14   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
  15   AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
  16   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  17   AC_CHECK_FUNCS_ONCE([fstatat])
  18
  19   if test $ac_cv_func_fstatat = no; then
  20     HAVE_FSTATAT=0
  21   else
  22     dnl Test for an AIX 7.1 bug; see
  23     dnl <http://lists.gnu.org/archive/html/bug-tar/2011-09/msg00015.html>.
  24     AC_CACHE_CHECK([whether fstatat (..., 0) works],
  25       [gl_cv_func_fstatat_zero_flag],
  26       [AC_RUN_IFELSE(
  27          [AC_LANG_SOURCE(
  28             [[
  29               #include <fcntl.h>
  30               #include <sys/stat.h>
  31               int
  32               main (void)
  33               {
  34                 struct stat a;
  35                 return fstatat (AT_FDCWD, ".", &a, 0) != 0;
  36               }
  37             ]])],
  38          [gl_cv_func_fstatat_zero_flag=yes],
  39          [gl_cv_func_fstatat_zero_flag=no],
  40          [case "$host_os" in
  41             aix*) gl_cv_func_fstatat_zero_flag="guessing no";;
  42             *)    gl_cv_func_fstatat_zero_flag="guessing yes";;
  43           esac
  44          ])
  45       ])
  46
  47     case $gl_cv_func_fstatat_zero_flag+$gl_cv_func_lstat_dereferences_slashed_symlink in
  48     *yes+*yes) ;;
  49     *) REPLACE_FSTATAT=1
  50        case $gl_cv_func_fstatat_zero_flag in
  51        *yes)
  52          AC_DEFINE([HAVE_WORKING_FSTATAT_ZERO_FLAG], [1],
  53            [Define to 1 if fstatat (..., 0) works.
  54             For example, it does not work in AIX 7.1.])
  55          ;;
  56        esac
  57        ;;
  58     esac
  59   fi
  60 ])