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emacs/m4/symlink.m4
Paul Eggert ae0d725005 [ChangeLog]
Work around some portability problems with symlinks.
* Makefile.in (GNULIB_MODULES): Add lstat, readlink, symlink.
* configure.in (lstat, HAVE_LSTAT): Remove special hack.
* lib/lstat.c, lib/readlink.c, lib/stat.c, lib/symlink.c:
* m4/dos.m4, m4/lstat.m4, m4/readlink.m4, m4/stat.m4, m4/symlink.m4:
New files, automatically generated from gnulib.
* aclocal.m4, configure, lib/Makefile.in, lib/gnulib.mk:
* lib/stdlib.in.h, m4/gl-comp.m4, m4/stdlib_h.m4: Regenerate.

2011-02-22  Paul Eggert  <eggert@cs.ucla.edu>
[src/ChangeLog]
Work around some portability problems with symlinks.
* fileio.c (Frename_file, Fmake_symbolic_link, Ffile_symlink_p):
Simplify the code by assuming that the readlink and symlink calls
exist, even if they always fail on this host.
(Ffile_readable_p): Likewise, for fifos.
* config.in: Regenerate.
2011-02-22 11:30:07 -08:00

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# serial 4
# See if we need to provide symlink replacement.
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.
# Written by Eric Blake.
AC_DEFUN([gl_FUNC_SYMLINK],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_CHECK_FUNCS_ONCE([symlink])
dnl The best we can do on mingw is provide a dummy that always fails, so
dnl that compilation can proceed with fewer ifdefs. On FreeBSD 7.2, AIX 7.1,
dnl and Solaris 9, we want to fix a bug with trailing slash handling.
if test $ac_cv_func_symlink = no; then
HAVE_SYMLINK=0
AC_LIBOBJ([symlink])
else
AC_CACHE_CHECK([whether symlink handles trailing slash correctly],
[gl_cv_func_symlink_works],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
]],
[[int result = 0;
if (!symlink ("a", "conftest.link/"))
result |= 1;
if (symlink ("conftest.f", "conftest.lnk2"))
result |= 2;
else if (!symlink ("a", "conftest.lnk2/"))
result |= 4;
return result;
]])],
[gl_cv_func_symlink_works=yes], [gl_cv_func_symlink_works=no],
[gl_cv_func_symlink_works="guessing no"])
rm -f conftest.f conftest.link conftest.lnk2])
if test "$gl_cv_func_symlink_works" != yes; then
REPLACE_SYMLINK=1
AC_LIBOBJ([symlink])
fi
fi
])