Unknown option: "-3" Unix manual page for swab. (host=minya system=Darwin)
SWAB(3)                  BSD Library Functions Manual                  SWAB(3)

NAME
     swab -- swap adjacent bytes

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     void
     swab(const void *restrict src, void *restrict dest, ssize_t nbytes);

DESCRIPTION
     The function swab() copies nbytes bytes from the location referenced by
     src to the location referenced by dest, swapping adjacent bytes.

     The argument nbytes should be an even number.  If nbytes is odd, swab()
     copies and exchanges nbytes -1 bytes and the disposition of the last byte
     is unspecified.  If copying takes place between objects that overlap, the
     behavior is undefined. If nbytes is negative, swab() does nothing.

SEE ALSO
     bzero(3), memset(3), compat(5)

HISTORY
     A swab() function appeared in Version 7 AT&T UNIX.

BSD                            February 24, 2010                           BSD