4.3BSD-UWisc/man/cat2/truncate.2

TRUNCATE(2)         UNIX Programmer's Manual          TRUNCATE(2)



NAME
     truncate - truncate a file to a specified length

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

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

DESCRIPTION
     _T_r_u_n_c_a_t_e causes the file named by _p_a_t_h or referenced by _f_d
     to be truncated to at most _l_e_n_g_t_h bytes in size.  If the
     file previously was larger than this size, the extra data is
     lost.  With _f_t_r_u_n_c_a_t_e, 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 _e_r_r_n_o speci-
     fies the error.

ERRORS
     _T_r_u_n_c_a_t_e succeeds unless:

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

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

     [ENAMETOOLONG] A component of a pathname exceeded 255 char-
                    acters, or an entire path name exceeded 1023
                    characters.

     [ENOENT]       The named file does not exist.

     [EACCES]       Search permission is denied for a component
                    of the path prefix.

     [EACCES]       The named file is not writable by the user.

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

     [EISDIR]       The named file is a directory.

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

     [ETXTBSY]      The file is a pure procedure (shared text)



Printed 12/27/86         March 29, 1986                         1






TRUNCATE(2)         UNIX Programmer's Manual          TRUNCATE(2)



                    file that is being executed.

     [EIO]          An I/O error occurred updating the inode.

     [EFAULT]       _P_a_t_h points outside the process's allocated
                    address space.

     _F_t_r_u_n_c_a_t_e succeeds unless:

     [EBADF]        The _f_d is not a valid descriptor.

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

     [EINVAL]       The _f_d is not open for writing.

SEE ALSO
     open(2)

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


































Printed 12/27/86         March 29, 1986                         2