How to provide BSD-style async. i/o on SYSV

[Patrick Woo]

Hi, I am trying to port a BSD TN3270 to a CLIPPER system (SYSV with BSD
extension).

In the program somewhere, it said

    ioctl (fd, FIOASYNC, (char *)&onoff);

SYSV has no support for async. i/o (not on clipper anyway), can someone tell
me what is involve to provide BSD-style async. i/o on a SYSV system.

Or even better if someone can tell me where I can get a PD TN3270 that 
run on a vanilla SYSV (one that has no async. i/o)

Thanks :-)
-- 
  Patrick Woo                ctycal!pat at calgary.UUCP
  Land Information Services                 or
  The City of Calgary       ...{alberta,ubc-cs,utai}!calgary!ctycal!pat