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1# strndup.m4 serial 21
2dnl Copyright (C) 2002-2003, 2005-2012 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_STRNDUP],
8[
9  dnl Persuade glibc <string.h> to declare strndup().
10  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
11
12  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
13  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
14  AC_CHECK_DECLS_ONCE([strndup])
15  AC_CHECK_FUNCS_ONCE([strndup])
16  if test $ac_cv_have_decl_strndup = no; then
17    HAVE_DECL_STRNDUP=0
18  fi
19
20  if test $ac_cv_func_strndup = yes; then
21    HAVE_STRNDUP=1
22    # AIX 4.3.3, AIX 5.1 have a function that fails to add the terminating '\0'.
23    AC_CACHE_CHECK([for working strndup], [gl_cv_func_strndup_works],
24      [AC_RUN_IFELSE([
25         AC_LANG_PROGRAM([[#include <string.h>
26                           #include <stdlib.h>]], [[
27#if !HAVE_DECL_STRNDUP
28  extern
29  #ifdef __cplusplus
30  "C"
31  #endif
32  char *strndup (const char *, size_t);
33#endif
34  char *s;
35  s = strndup ("some longer string", 15);
36  free (s);
37  s = strndup ("shorter string", 13);
38  return s[13] != '\0';]])],
39         [gl_cv_func_strndup_works=yes],
40         [gl_cv_func_strndup_works=no],
41         [
42changequote(,)dnl
43          case $host_os in
44            aix | aix[3-6]*) gl_cv_func_strndup_works="guessing no";;
45            *)               gl_cv_func_strndup_works="guessing yes";;
46          esac
47changequote([,])dnl
48         ])])
49    case $gl_cv_func_strndup_works in
50      *no) REPLACE_STRNDUP=1 ;;
51    esac
52  else
53    HAVE_STRNDUP=0
54  fi
55])
56