sysdeps/posix/truncate.c

   1 /* Truncate a file given by name.  Generic POSIX.1 version.
   2    Copyright (C) 1995-2016 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sys/types.h>
  20 #include <errno.h>
  21 #include <unistd.h>
  22 #include <fcntl.h>
  23
  24 /* Truncate PATH to LENGTH bytes.  */
  25 int
  26 __truncate (const char *path, off_t length)
  27 {
  28   int fd, ret, save;
  29
  30   fd = __open (path, O_WRONLY | (length == 0 ? O_TRUNC : 0));
  31   if (fd < 0)
  32     return -1;
  33
  34   if (length == 0)
  35     ret = 0;
  36   else
  37     ret = __ftruncate (fd, length);
  38   save = errno;
  39   (void) __close (fd);
  40   if (ret < 0)
  41     __set_errno (save);
  42   return ret;
  43 }
  44 weak_alias (__truncate, truncate)