X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Freadlink.m4;h=a502ca560fe4835805fb4c4b2013e28fb95e0668;hb=c9ff025783e5374226ffbf7940f40ce7db6852ed;hp=1c347a0c9aea01c66c530eb37127403b88ed8847;hpb=c14bbe8dfae3a0f12940186f45e3dfb689c3e57d;p=gnulib.git

diff --git a/m4/readlink.m4 b/m4/readlink.m4
index 1c347a0c9..a502ca560 100644
--- a/m4/readlink.m4
+++ b/m4/readlink.m4
@@ -1,5 +1,5 @@
-# readlink.m4 serial 4
-dnl Copyright (C) 2003, 2007 Free Software Foundation, Inc.
+# readlink.m4 serial 9
+dnl Copyright (C) 2003, 2007, 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.
@@ -10,8 +10,41 @@ AC_DEFUN([gl_FUNC_READLINK],
   AC_CHECK_FUNCS_ONCE([readlink])
   if test $ac_cv_func_readlink = no; then
     HAVE_READLINK=0
-    AC_LIBOBJ(readlink)
+    AC_LIBOBJ([readlink])
     gl_PREREQ_READLINK
+  else
+    AC_CACHE_CHECK([whether readlink signature is correct],
+      [gl_cv_decl_readlink_works],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+      /* Cause compilation failure if original declaration has wrong type.  */
+      ssize_t readlink (const char *, char *, size_t);]])],
+         [gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
+    dnl Solaris 9 ignores trailing slash.
+    dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
+    AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
+      [gl_cv_func_readlink_works],
+      [# We have readlink, so assume ln -s works.
+       ln -s conftest.no-such conftest.link
+       ln -s conftest.link conftest.lnk2
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+]], [[char buf[20];
+      return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
+         [gl_cv_func_readlink_works=yes], [gl_cv_func_readlink_works=no],
+         [gl_cv_func_readlink_works="guessing no"])
+      rm -f conftest.link conftest.lnk2])
+    if test "$gl_cv_func_readlink_works" != yes; then
+      AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
+        fails to recognize a trailing slash.])
+      REPLACE_READLINK=1
+      AC_LIBOBJ([readlink])
+    elif test "$gl_cv_decl_readlink_works" != yes; then
+      REPLACE_READLINK=1
+      AC_LIBOBJ([readlink])
+    fi
   fi
 ])