Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!umich!yale!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!lavaca.uh.edu!uhnix1!moray!urchin!p4694.f506.n106.z1.fidonet.org!Lynn.Lively
From: Lynn.Lively@p4694.f506.n106.z1.fidonet.org (Lynn Lively)
Newsgroups: comp.lang.c
Subject: indirect reference/use of procedures
Message-ID: <16702.25FE80FA@urchin.fidonet.org>
Date: 12 Mar 90 21:58:16 GMT
Sender: ufgate@urchin.fidonet.org (newsout1.26)
Organization: FidoNet node 1:106/506.4694 - Fulcrum's Edge, Spring TX
Lines: 81

In an article of <9 Mar 90 04:51:51 GMT>, cynthia@ucselx.sdsu.edu (cynthia Anderson) writes:

 cA>From: cynthia@ucselx.sdsu.edu (cynthia Anderson)
 cA>Date: 9 Mar 90 04:51:51 GMT
 cA>Organization: San Diego State University Computing Services
 cA>Message-ID: <1990Mar9.045151.9601@ucselx.sdsu.edu>
 cA>Newsgroups: comp.lang.c
 cA>
 cA>hello
 cA>
 cA>i would like to be able to write a procedure that takes as
 cA>a parameter a procedure name and then using that name
 cA>calls the procedure.
 cA>
 cA>ie  runAProcedure(myProcedure)
 cA>   {
 cA>
 cA>
 cA>        myProcedure
 cA>
 cA>
 cA>}
 cA>
 cA>Is this possible to do in C?  Any help or advise is appreciated
 cA>tho please e-mail responses so the net won't be cluttered.
 cA>
 cA>thanks,
 cA>
 cA>cynthia anderson
 cA><cynthia@cod.nosc.mil.uucp>
 cA>or
 cA><cynthia@ucselx.sdsu.edu>
 cA>
 cA>Disclaimer: whenever it was and whenever it happened, i'm sure i 
 cA>wasn't there and it couldn't have been me.
 cA>t

 Cynthia,
     Not only is it possible it's actually fairly easy to do. You need to  
declare your function in the following form.

<returntype> (* funcname) ();

Examples:

int  (* myfunc)();
void (* myfunc)();

use it in the program like this

myfunc ();

If it uses parameters simply specify them at call time.

myfunc (param1, param2);

of course my the declaration is only a pointer so make sure you initialize it  
to something. Hence you could do this.

int (* myprint) () = printf;

myprint ("Hello World!\n");

You can also set up tables of them if you like.

typedef INTFUNC int (* func)();

INTFUNC func_tab[10];

and later on refer to 

func_tab[1]();

Hope this helps.

 Your Servant,
      Lynn