compiler/posixc/truncate.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     POSIX.1-2008 function truncate().
   6 */
   7
   8 #include <unistd.h>
   9 #include <errno.h>
  10 #include <fcntl.h>
  11
  12 /*****************************************************************************
  13
  14     NAME */
  15 #include <unistd.h>
  16
  17         int truncate (
  18
  19 /*  SYNOPSIS */
  20         const char *path,
  21         off_t       length)
  22
  23 /*  FUNCTION
  24         Truncate a file to a specified length
  25
  26     INPUTS
  27         path   - the path of the file being truncated
  28         lenght - The file will have at most this size
  29
  30     RESULT
  31         0 on success or -1 on errorr.
  32
  33     NOTES
  34         If the file previously was larger than this size, the extra  data
  35         is  lost.   If  the  file  previously  was  shorter, it is
  36         unspecified whether the  file  is  left  unchanged  or  is
  37         extended.  In  the  latter case the extended part reads as
  38         zero bytes.
  39
  40
  41     EXAMPLE
  42
  43     BUGS
  44
  45     SEE ALSO
  46         open()
  47
  48     INTERNALS
  49
  50 ******************************************************************************/
  51 {
  52     int fd, ret = -1;
  53
  54     if (!path) /* safety check */
  55     {
  56         errno = EFAULT;
  57         return -1;
  58     }
  59
  60     if ((fd = open(path, O_WRONLY)) != -1)
  61     {
  62         ret = ftruncate(fd, length);
  63         close(fd);
  64     }
  65
  66     return ret;
  67 }