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From: guy@gorodish.UUCP
Newsgroups: comp.lang.c
Subject: Re: Function prototypes versus open()
Message-ID: <20538@sun.uucp>
Date: Sat, 6-Jun-87 16:03:54 EDT
Article-I.D.: sun.20538
Posted: Sat Jun  6 16:03:54 1987
Date-Received: Sun, 7-Jun-87 10:24:37 EDT
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> Wait a sec. Would you please explain how the following can be done:
> 
> I have a dispatcher routine, that takes a pointer to a function, some args,
> does some munching on the args, and calls the pointed to routine with 3,
> 4, or 5 args. Each routine called is expecting a known, fixed # of args,
> yet the pointer used is with variable args. So, according to the above,
> I have to declare the function pointer as variable args, which activates
> one calling convention, yet the routines are fixed args, and expecting
> another calling convention.

Trivial.  Have the argument to the dispatcher, instead of being a
pointer to a function with a variable number of arguments, be a union
of a pointer to a function with three arguments, a pointer to a
function with four arguments, and a pointer to a function with five
arguments.  Since you have three separate calls, use the three
different members of the union in the three calls.  End of problem.
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com