1# readlink.m4 serial 11
2dnl Copyright (C) 2003, 2007, 2009-2011 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_FUNC_READLINK],
8[
9  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
10  AC_CHECK_FUNCS_ONCE([readlink])
11  if test $ac_cv_func_readlink = no; then
12    HAVE_READLINK=0
13  else
14    AC_CACHE_CHECK([whether readlink signature is correct],
15      [gl_cv_decl_readlink_works],
16      [AC_COMPILE_IFELSE(
17         [AC_LANG_PROGRAM(
18           [[#include <unistd.h>
19      /* Cause compilation failure if original declaration has wrong type.  */
20      ssize_t readlink (const char *, char *, size_t);]])],
21         [gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
22    dnl Solaris 9 ignores trailing slash.
23    dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
24    AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
25      [gl_cv_func_readlink_works],
26      [# We have readlink, so assume ln -s works.
27       ln -s conftest.no-such conftest.link
28       ln -s conftest.link conftest.lnk2
29       AC_RUN_IFELSE(
30         [AC_LANG_PROGRAM(
31           [[#include <unistd.h>
32]], [[char buf[20];
33      return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
34         [gl_cv_func_readlink_works=yes], [gl_cv_func_readlink_works=no],
35         [gl_cv_func_readlink_works="guessing no"])
36      rm -f conftest.link conftest.lnk2])
37    if test "$gl_cv_func_readlink_works" != yes; then
38      AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
39        fails to recognize a trailing slash.])
40      REPLACE_READLINK=1
41    elif test "$gl_cv_decl_readlink_works" != yes; then
42      REPLACE_READLINK=1
43    fi
44  fi
45])
46
47# Like gl_FUNC_READLINK, except prepare for separate compilation
48# (no REPLACE_READLINK, no AC_LIBOBJ).
49AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
50[
51  AC_CHECK_FUNCS_ONCE([readlink])
52  gl_PREREQ_READLINK
53])
54
55# Prerequisites of lib/readlink.c.
56AC_DEFUN([gl_PREREQ_READLINK],
57[
58  :
59])
60