truncate(2)                                           truncate(2)



     NAME
          truncate, ftruncate - truncate a file to a specified length

     SYNOPSIS
          int truncate(path, length)
          char *path;
          int length;

          int ftruncate(fd, length)
          int fd, length;

     DESCRIPTION
          truncate causes the file named by path or referenced by fd
          to be truncated to at most length bytes in size.  If the
          file previously was larger than this size, the extra data is
          lost.  With ftruncate, the file must be open for writing.

     RETURN VALUES
          A value of 0 is returned if the call succeeds.  If the call
          fails a -1 is returned and the global variable errno speci-
          fies the error.

     ERRORS
          truncate will fail if:

          [EPERM]      The pathname contains a character with the
                       high-order bit set.

          [ENOENT]     The pathname was too long.

          [ENOTDIR]    A component of the path prefix of path is not a
                       directory.

          [EPERM]      A pathname contains a character with the high-
                       order bit set.

          [ENAMETOOLONG]
                       A component of a pathname exceeded NAME_MAX
                       characters, or an entire pathname exceeded
                       PATH_MAX.

          [ELOOP]      Too many symbolic links were encountered in
                       translating a pathname.

          [ENOENT]     The named file does not exist.

          [EACCES]     A component of the path prefix denies search
                       permission.

          [EISDIR]     The named file is a directory.

          [EROFS]      The named file resides on a read-only file sys-



     April, 1990                                                     1

     truncate(2)                                           truncate(2)



                       tem.

          [ETXTBSY]    The file is a pure procedure (shared text) file
                       that is being executed.

                          Note:  If you are running an NFS system
                          and you are accessing a shared binary re-
                          motely, it is possible that you will not
                          get this errno.


          [EFAULT]     name points outside the process's allocated ad-
                       dress space.

          ftruncate will fail if:

          [EBADF]        The fd is not a valid descriptor.

          [EINVAL]       The fd references a socket, not a file.

     SEE ALSO
          open(2).

     BUGS
          Partial blocks discarded as the result of truncation are not
          zero filled; this can result in holes in files which do not
          read as zero.

          These calls should be generalized to allow ranges of bytes
          in a file to be discarded.

























     2                                                     April, 1990