string/stpncpy.c

   1 /* Copyright (C) 1993-2023 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    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifdef HAVE_CONFIG_H
  19 # include <config.h>
  20 #endif
  21
  22 #ifdef _LIBC
  23 # include <string.h>
  24 #else
  25 # include <sys/types.h>
  26 #endif
  27
  28 #ifndef STPNCPY
  29 # ifdef weak_alias
  30 #  define STPNCPY       __stpncpy
  31 weak_alias (__stpncpy, stpncpy)
  32 # else
  33 #  define STPNCPY       stpncpy
  34 # endif
  35 #endif
  36
  37 /* Copy no more than N characters of SRC to DEST, returning the address of
  38    the terminating '\0' in DEST, if any, or else DEST + N.  */
  39 char *
  40 STPNCPY (char *dest, const char *src, size_t n)
  41 {
  42   size_t size = __strnlen (src, n);
  43   memcpy (dest, src, size);
  44   dest += size;
  45   if (size == n)
  46     return dest;
  47   return memset (dest, '\0', n - size);
  48 }
  49 #ifdef weak_alias
  50 libc_hidden_def (__stpncpy)
  51 #endif