1# double-slash-root.m4 serial 2   -*- Autoconf -*-
2dnl Copyright (C) 2006 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7AC_DEFUN([gl_DOUBLE_SLASH_ROOT],
8[
9  AC_REQUIRE([AC_CANONICAL_HOST])
10  AC_CACHE_CHECK([whether // is distinct from /], [gl_cv_double_slash_root],
11    [ if test x"$cross_compiling" = xyes ; then
12	# When cross-compiling, there is no way to tell whether // is special
13	# short of a list of hosts.  However, the only known hosts to date
14	# that have a distinct // are Apollo DomainOS (too old to port to),
15	# Cygwin, and z/OS.  If anyone knows of another system for which // has
16	# special semantics and is distinct from /, please report it to
17	# <bug-gnulib@gnu.org>.
18	case $host in
19	  *-cygwin | i370-ibm-openedition)
20	    gl_cv_double_slash_root=yes ;;
21	  *)
22	    # Be optimistic and assume that / and // are the same when we
23	    # don't know.
24	    gl_cv_double_slash_root='unknown, assuming no' ;;
25	esac
26      else
27	set x `ls -di / //`
28	if test $[2] = $[4] && wc //dev/null >/dev/null 2>&1; then
29	  gl_cv_double_slash_root=no
30	else
31	  gl_cv_double_slash_root=yes
32	fi
33      fi])
34  if test "$gl_cv_double_slash_root" = yes; then
35    AC_DEFINE([DOUBLE_SLASH_IS_DISTINCT_ROOT], 1,
36      [Define to 1 if // is a file system root distinct from /.])
37  fi
38])
39