2 dnl Copyright (C) 2002-2003, 2005-2007, 2009 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 AC_DEFUN([gl_FUNC_STPNCPY],
9 dnl Persuade glibc <string.h> to declare stpncpy().
10 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
12 dnl The stpncpy() declaration in lib/string.in.h uses 'restrict'.
13 AC_REQUIRE([AC_C_RESTRICT])
15 AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
17 dnl Both glibc and AIX (4.3.3, 5.1) have an stpncpy() function
18 dnl declared in <string.h>. Its side effects are the same as those
20 dnl stpncpy (dest, src, n)
21 dnl overwrites dest[0..n-1], min(strlen(src),n) bytes coming from src,
22 dnl and the remaining bytes being NULs. However, the return value is
23 dnl in glibc: dest + min(strlen(src),n)
24 dnl in AIX: dest + max(0,n-1)
25 dnl Only the glibc return value is useful in practice.
27 AC_CACHE_CHECK([for working stpncpy], [gl_cv_func_stpncpy], [
30 #include <string.h> /* for strcpy */
31 /* The stpncpy prototype is missing in <string.h> on AIX 4. */
32 extern char *stpncpy (char *dest, const char *src, size_t n);
34 const char *src = "Hello";
36 /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+1 here. */
37 strcpy (dest, "\377\377\377\377\377\377");
38 if (stpncpy (dest, src, 2) != dest + 2) exit(1);
39 /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+4 here. */
40 strcpy (dest, "\377\377\377\377\377\377");
41 if (stpncpy (dest, src, 5) != dest + 5) exit(1);
42 /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+6 here. */
43 strcpy (dest, "\377\377\377\377\377\377");
44 if (stpncpy (dest, src, 7) != dest + 5) exit(1);
47 ], gl_cv_func_stpncpy=yes, gl_cv_func_stpncpy=no,
48 [AC_EGREP_CPP([Thanks for using GNU], [
50 #ifdef __GNU_LIBRARY__
53 ], gl_cv_func_stpncpy=yes, gl_cv_func_stpncpy=no)])])
55 if test $gl_cv_func_stpncpy = yes; then
56 AC_DEFINE([HAVE_STPNCPY], [1],
57 [Define if you have the stpncpy() function and it works.])
65 # Prerequisites of lib/stpncpy.c.
66 AC_DEFUN([gl_PREREQ_STPNCPY], [