string/strncpy.c

   1 /* Copyright (C) 1991-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <string.h>
  19
  20 #undef strncpy
  21
  22 #ifndef STRNCPY
  23  #define STRNCPY strncpy
  24 #endif
  25
  26 char *
  27 STRNCPY (char *s1, const char *s2, size_t n)
  28 {
  29   size_t size = __strnlen (s2, n);
  30   if (size != n)
  31     memset (s1 + size, '\0', n - size);
  32   return memcpy (s1, s2, size);
  33 }
  34 libc_hidden_builtin_def (strncpy)