1# stpncpy.m4 serial 16 2dnl Copyright (C) 2002-2003, 2005-2007, 2009-2014 Free Software Foundation, 3dnl Inc. 4dnl This file is free software; the Free Software Foundation 5dnl gives unlimited permission to copy and/or distribute it, 6dnl with or without modifications, as long as this notice is preserved. 7 8AC_DEFUN([gl_FUNC_STPNCPY], 9[ 10 dnl Persuade glibc <string.h> to declare stpncpy(). 11 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) 12 13 dnl The stpncpy() declaration in lib/string.in.h uses 'restrict'. 14 AC_REQUIRE([AC_C_RESTRICT]) 15 16 AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS]) 17 18 dnl Both glibc and AIX (4.3.3, 5.1) have an stpncpy() function 19 dnl declared in <string.h>. Its side effects are the same as those 20 dnl of strncpy(): 21 dnl stpncpy (dest, src, n) 22 dnl overwrites dest[0..n-1], min(strlen(src),n) bytes coming from src, 23 dnl and the remaining bytes being NULs. However, the return value is 24 dnl in glibc: dest + min(strlen(src),n) 25 dnl in AIX: dest + max(0,n-1) 26 dnl Only the glibc return value is useful in practice. 27 28 AC_CHECK_DECLS_ONCE([stpncpy]) 29 AC_CHECK_FUNCS_ONCE([stpncpy]) 30 if test $ac_cv_func_stpncpy = yes; then 31 AC_CACHE_CHECK([for working stpncpy], [gl_cv_func_stpncpy], [ 32 AC_RUN_IFELSE( 33 [AC_LANG_SOURCE([[ 34#include <stdlib.h> 35#include <string.h> /* for strcpy */ 36/* The stpncpy prototype is missing in <string.h> on AIX 4. */ 37#if !HAVE_DECL_STPNCPY 38extern 39# ifdef __cplusplus 40"C" 41# endif 42char *stpncpy (char *dest, const char *src, size_t n); 43#endif 44int main () 45{ 46 int result = 0; 47 const char *src = "Hello"; 48 char dest[10]; 49 /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+1 here. */ 50 { 51 strcpy (dest, "\377\377\377\377\377\377"); 52 if (stpncpy (dest, src, 2) != dest + 2) 53 result |= 1; 54 } 55 /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+4 here. */ 56 { 57 strcpy (dest, "\377\377\377\377\377\377"); 58 if (stpncpy (dest, src, 5) != dest + 5) 59 result |= 2; 60 } 61 /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+6 here. */ 62 { 63 strcpy (dest, "\377\377\377\377\377\377"); 64 if (stpncpy (dest, src, 7) != dest + 5) 65 result |= 4; 66 } 67 return result; 68} 69]])], 70 [gl_cv_func_stpncpy=yes], 71 [gl_cv_func_stpncpy=no], 72 [AC_EGREP_CPP([Thanks for using GNU], [ 73#include <features.h> 74#ifdef __GNU_LIBRARY__ 75 Thanks for using GNU 76#endif 77], [gl_cv_func_stpncpy="guessing yes"], [gl_cv_func_stpncpy="guessing no"]) 78 ]) 79 ]) 80 case "$gl_cv_func_stpncpy" in 81 *yes) 82 AC_DEFINE([HAVE_STPNCPY], [1], 83 [Define if you have the stpncpy() function and it works.]) 84 ;; 85 *) 86 REPLACE_STPNCPY=1 87 ;; 88 esac 89 else 90 HAVE_STPNCPY=0 91 fi 92]) 93 94# Prerequisites of lib/stpncpy.c. 95AC_DEFUN([gl_PREREQ_STPNCPY], [ 96 : 97]) 98