SYNOPSIS
       #include <unistd.h>

       int truncate(const char *path, off_t length);


DESCRIPTION
       The  truncate()  function shall cause the regular file named by path to
       have a size which shall be equal to length bytes.

       If the file previously was larger than length, the extra data  is  dis-
       carded.  If  the  file  was previously shorter than length, its size is
       increased, and the extended area appears as if it were zero-filled.

       The application shall ensure that the process has write permission  for
       the file.

       If  the  request would cause the file size to exceed the soft file size
       limit for the process, the request shall fail  and  the  implementation
       shall generate the SIGXFSZ signal for the process.

       This  function  shall  not  modify  the  file  offset for any open file
       descriptions associated with the file. Upon successful  completion,  if
       the  file  size  is  changed,  this  function shall mark for update the
       st_ctime and st_mtime fields of the file, and the S_ISUID  and  S_ISGID
       bits of the file mode may be cleared.

RETURN VALUE
       Upon  successful  completion,  truncate() shall return 0. Otherwise, -1
       shall be returned, and errno set to indicate the error.

ERRORS
       The truncate() function shall fail if:

       EINTR  A signal was caught during execution.

       EINVAL The length argument was less than 0.

       EFBIG or EINVAL
              The length argument was greater than the maximum file size.

       EIO    An I/O error occurred while reading from or writing  to  a  file
              system.

       EACCES A  component  of  the  path  prefix denies search permission, or
              write permission is denied on the file.

       EISDIR The named file is a directory.

       ELOOP  A loop exists in symbolic links encountered during resolution of
              the path argument.

       ENAMETOOLONG
       The truncate() function may fail if:

       ELOOP  More  than  {SYMLOOP_MAX} symbolic links were encountered during
              resolution of the path argument.

       ENAMETOOLONG
              Pathname resolution of a symbolic link produced an  intermediate
              result whose length exceeds {PATH_MAX}.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       open()   ,   the   Base  Definitions  volume  of  IEEE Std 1003.1-2001,
       <unistd.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .