# fstatat.m4 serial 3

dnl Copyright (C) 2004-2017 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.

# Written by Jim Meyering.

# If we have the fstatat function, and it has the bug (in AIX 7.1)

# that it does not fill in st_size correctly, use the replacement function.

AC_DEFUN([gl_FUNC_FSTATAT],

[

  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])

  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])

  AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  AC_CHECK_FUNCS_ONCE([fstatat])

  if test $ac_cv_func_fstatat = no; then

    HAVE_FSTATAT=0

  else

    dnl Test for an AIX 7.1 bug; see

    dnl <http://lists.gnu.org/archive/html/bug-tar/2011-09/msg00015.html>.

    AC_CACHE_CHECK([whether fstatat (..., 0) works],

      [gl_cv_func_fstatat_zero_flag],

      [AC_RUN_IFELSE(

         [AC_LANG_SOURCE(

            [[

              #include <fcntl.h>

              #include <sys/stat.h>

              int

              main (void)

              {

                struct stat a;

                return fstatat (AT_FDCWD, ".", &a, 0) != 0;

              }

            ]])],

         [gl_cv_func_fstatat_zero_flag=yes],

         [gl_cv_func_fstatat_zero_flag=no],

         [case "$host_os" in

            aix*) gl_cv_func_fstatat_zero_flag="guessing no";;

            *)    gl_cv_func_fstatat_zero_flag="guessing yes";;

          esac

         ])

      ])

    case $gl_cv_func_fstatat_zero_flag+$gl_cv_func_lstat_dereferences_slashed_symlink in

    *yes+*yes) ;;

    *) REPLACE_FSTATAT=1

       case $gl_cv_func_fstatat_zero_flag in

       *yes)

         AC_DEFINE([HAVE_WORKING_FSTATAT_ZERO_FLAG], [1],

           [Define to 1 if fstatat (..., 0) works.

            For example, it does not work in AIX 7.1.])

         ;;

       esac

       ;;

    esac

  fi

])