sfs@hou2a.UUCP (S.STUMPF) (05/08/84)
Could someone please tell me what this file is for?
I have some code that has this line in a few files.
I am compiling without it and looking at the errors
and I am getting absolutely nowhere. Any clues as
to what it is and how to write one? Thanks.
-- until the lips are blue --
Jon S. Stumpf @ the beach
{allegra|ihnp4}!hocoer!jss
Note: the above does not match headersteiny@scc.UUCP (Don Steiny) (05/12/84)
*** <sys/mx.h> - is the definations needed for the mpxcall(2) system call. V7 "had" this great scheme called multiplexed i/o. According to the manual, it allowed the user to set up interprocess "channels" so that more that processes could communicate with each other. There was a special type of file called a "multiplexed file". Any number of processes could open the file. "mx.h" contains the definations for the headers and control messages. The catch was, that even though there were manual pages (see mpx(2), mpxio(4), mx(5) - in the V7 manual), it did not work. UCB managed to get it to work on 4.1bsd, but it does not work in regular V7. UCB has a couple of programs that use it (comsat). Code that uses mpx has to be rewritten using messages on System V. Don Steiny Personetics
guy@rlgvax.UUCP (Guy Harris) (05/17/84)
> Code that uses mpx has to be rewritten using messages on System V.
Or to use sockets in 4.2BSD; Berkeley canned multiplexed files as well.
Guy Harris
{seismo,ihnp4,allegra}!rlgvax!guy
P.S. It takes about a day's work (at most) to get System V message queues up
under 4.2BSD, and they're a bit faster than UNIX-domain stream sockets.
Unfortunately, the UNIX domain doesn't have "reliably delivered messages",
so I couldn't benchmark them against messages.