v7 man page for mpxcall

MPXCALL(2)							System Calls Manual							MPXCALL(2)

NAME
       mpxcall - multiplexor and channel interface

SYNOPSIS
       mpxcall(arg1, arg2, arg3, cmd)

DESCRIPTION
       Mpxcall	supplies  a primitive interface to the kernel used by the routines listed below.  Each routine that uses mpxcall passes an integer
       cmd as the fourth argument.  These are defined in /usr/include/mx.h.  Mpxcall always returns an integer	which  is  to  be  interpreted	in
       accordance with the definition of cmd.

SEE ALSO
       group(2), join(2), extract(2), connect(2), chan(2), attach(2), detach(2)

DIAGNOSTICS
       The value -1 is returned on error.

																	MPXCALL(2)