strndup.c revision 1.9
1/* Implement the strndup function. 2 Copyright (C) 2005-2019 Free Software Foundation, Inc. 3 Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>. 4 5This file is part of the libiberty library. 6Libiberty is free software; you can redistribute it and/or 7modify it under the terms of the GNU Library General Public 8License as published by the Free Software Foundation; either 9version 2 of the License, or (at your option) any later version. 10 11Libiberty is distributed in the hope that it will be useful, 12but WITHOUT ANY WARRANTY; without even the implied warranty of 13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14Library General Public License for more details. 15 16You should have received a copy of the GNU Library General Public 17License along with libiberty; see the file COPYING.LIB. If 18not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, 19Boston, MA 02110-1301, USA. */ 20 21/* 22 23@deftypefn Extension char* strndup (const char *@var{s}, size_t @var{n}) 24 25Returns a pointer to a copy of @var{s} with at most @var{n} characters 26in memory obtained from @code{malloc}, or @code{NULL} if insufficient 27memory was available. The result is always NUL terminated. 28 29@end deftypefn 30 31*/ 32 33#include "ansidecl.h" 34#include <stddef.h> 35 36extern size_t strnlen (const char *s, size_t maxlen); 37extern PTR malloc (size_t); 38extern PTR memcpy (PTR, const PTR, size_t); 39 40char * 41strndup (const char *s, size_t n) 42{ 43 char *result; 44 size_t len = strnlen (s, n); 45 46 result = (char *) malloc (len + 1); 47 if (!result) 48 return 0; 49 50 result[len] = '\0'; 51 return (char *) memcpy (result, s, len); 52} 53