AC_DEFUN([gl_FUNC_DIRFD],
[
AC_REQUIRE([AC_PROG_CPP])
AC_REQUIRE([AC_PROG_EGREP])
AC_CHECK_FUNCS(dirfd)
AC_CHECK_DECLS([dirfd], , ,
[
AC_CACHE_CHECK([whether dirfd is a macro],
gl_cv_func_dirfd_macro,
[AC_EGREP_CPP([dirent_header_defines_dirfd], [
dirent_header_defines_dirfd
gl_cv_func_dirfd_macro=yes,
gl_cv_func_dirfd_macro=no)])
if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd,$gl_cv_func_dirfd_macro \
= no,no,no; then
AC_REPLACE_FUNCS([dirfd])
AC_CACHE_CHECK(
[how to get the file descriptor associated with an open DIR*],
gl_cv_sys_dir_fd_member_name,
[
dirfd_save_CFLAGS=$CFLAGS
for ac_expr in d_fd dd_fd; do
CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
AC_TRY_COMPILE(
[ [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
dir_fd_found=yes
)
CFLAGS=$dirfd_save_CFLAGS
test "$dir_fd_found" = yes && break
done
test "$dir_fd_found" = yes || ac_expr=no_such_member
gl_cv_sys_dir_fd_member_name=$ac_expr
]
)
if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
$gl_cv_sys_dir_fd_member_name,
[the name of the file descriptor member of DIR])
fi
AH_VERBATIM(DIR_TO_FD,
[])
fi
])