X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Freadlink.m4;h=107083f7c7249a9c870010c17de792de850f82cb;hb=a425462f784164b73297d8992075fd9aebd65a94;hp=083456551629f05711ee59dca89b958db694b0a7;hpb=d52c5b93a562113d859c264bbb92f5c0b8c5ae77;p=gnulib.git

diff --git a/m4/readlink.m4 b/m4/readlink.m4
index 083456551..107083f7c 100644
--- a/m4/readlink.m4
+++ b/m4/readlink.m4
@@ -1,5 +1,5 @@
-# readlink.m4 serial 3
-dnl Copyright (C) 2003, 2007 Free Software Foundation, Inc.
+# readlink.m4 serial 11
+dnl Copyright (C) 2003, 2007, 2009-2012 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.
@@ -7,14 +7,51 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_READLINK],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-  AC_CHECK_FUNCS(readlink)
+  AC_CHECK_FUNCS_ONCE([readlink])
   if test $ac_cv_func_readlink = no; then
     HAVE_READLINK=0
-    AC_LIBOBJ(readlink)
-    gl_PREREQ_READLINK
+  else
+    AC_CACHE_CHECK([whether readlink signature is correct],
+      [gl_cv_decl_readlink_works],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+      /* Cause compilation failure if original declaration has wrong type.  */
+      ssize_t readlink (const char *, char *, size_t);]])],
+         [gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
+    dnl Solaris 9 ignores trailing slash.
+    dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
+    AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
+      [gl_cv_func_readlink_works],
+      [# We have readlink, so assume ln -s works.
+       ln -s conftest.no-such conftest.link
+       ln -s conftest.link conftest.lnk2
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <unistd.h>
+]], [[char buf[20];
+      return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
+         [gl_cv_func_readlink_works=yes], [gl_cv_func_readlink_works=no],
+         [gl_cv_func_readlink_works="guessing no"])
+      rm -f conftest.link conftest.lnk2])
+    if test "$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
+    elif test "$gl_cv_decl_readlink_works" != yes; then
+      REPLACE_READLINK=1
+    fi
   fi
 ])
 
+# Like gl_FUNC_READLINK, except prepare for separate compilation
+# (no REPLACE_READLINK, no AC_LIBOBJ).
+AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
+[
+  AC_CHECK_FUNCS_ONCE([readlink])
+  gl_PREREQ_READLINK
+])
+
 # Prerequisites of lib/readlink.c.
 AC_DEFUN([gl_PREREQ_READLINK],
 [