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From: cim2@pyuxv.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: Finding the address of functions in MSC, and the ^C interupt
Message-ID: <283@pyuxv.UUCP>
Date: Thu, 30-Apr-87 09:02:54 EDT
Article-I.D.: pyuxv.283
Posted: Thu Apr 30 09:02:54 1987
Date-Received: Sat, 2-May-87 02:26:53 EDT
References: <2042@hoptoad.uucp>
Organization: CHC
Lines: 40

[Long example of setting interrupts via set/getting interrupts using
MSC]

Several  things come to mind:

1. There is no need to do this at all in MSC since they provide the
   signal() handler function - to call bye() when the user types CTRL-C
   just do:

   #include <signal.h>

   main()
   {
   	int	bye();

	signal(SIGINT,bye);

   }

2.  If you need to set interrupt vectors for some other reason (e.g. an
    RTL) the FP_SEG and FP_OFF macros give weird results when fed a
    function pointer - ( I was working on MSC 4.0 in Large memory model)
    It seems these only really work with variables (Is this a bug?)

    For my application, I coerced the function pointer to a long,
    and then split the segment/offset off:

    unsigned	long	lvar;
    int		bye();
    int		seg,off;

    lvar=(unsigned long)bye;
    off= lvar&0xFF;
    seg= lvar>>16;

    I know this looks kludgy - but it works :)

Rob Fair
Bellcore/CHC