Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ukma!gatech!udel!mmdf
From: AXDRW%ALASKA.BITNET@cunyvm.cuny.edu (Don R. Withey)
Newsgroups: comp.sys.amiga
Subject: Prototyping function pointers
Message-ID: <14424@louie.udel.EDU>
Date: 1 May 89 18:42:27 GMT
Sender: mmdf@udel.EDU
Lines: 46

How does one prototype a function pointer in Lattice 5.02?  I have a function
pointer that I want to force Lattice to pass the arguments in certain
registers.  For example:

        extern __far __asm MyFunc(register __a0 struct Window *);
        ...
        {
        ...
        MyFunc(Win);
        ...
        }

This works fine, basically it boils down to:
        movea.l Win,A0 (I may have the order wrong (A0, Win))
        jsr     _MyFunc

Now if I want to do the same thing, except MyFunc is a function pointer,
how do I do it?

        extern __far __asm MyFunc(register __a0 struct Window *);
        ...
        {
        __fptr  MyFunc;
        ...
        MyFunc = SetFunction(...);
        ...
        MyFunc(Win);
        ...
        }

This doesn't work that way I want it to, it basically does the following:
        pushal  Win     (Vax assembler ;-)
        movea.l MyFunc,A0 (It just happend to use A0, I think)
        jsr (A0)
        (clean up the stack)

Anyway, It basically ignores the earlier declaration.  What I want it for is,
I'm setfunctioning a routine, and if my new function fails, I want to call the
old function.
        Don
-----------------------------------------------------------
Don R Withey                    BITNET: AXDRW@ALASKA.BITNET
University of Alaska            BIX:    dwithey
3211 U.A.A. Drive               Phone:  907-786-1074 (work)
Anchorage, Alaska  99508        Phone:  907-344-4057 (home)
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