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From: shankar@hpclscu.HP.COM (Shankar Unni)
Newsgroups: comp.lang.c++
Subject: Re: pointer to function in varargs arguments
Message-ID: <58170010@hpclscu.HP.COM>
Date: 21 Mar 90 02:28:06 GMT
References: <1990Mar19.190923.12448@elroy.jpl.nasa.gov>
Organization: Hewlett-Packard Calif. Language Lab
Lines: 40

> 	void (a::*func_ptr)(char*) = &a::proc;
> ...
> 	proc2(func_ptr);
> ...
> (proc2 is not a member function of a.) 
> ...
> However, func_ptr is not what it seems. It is not a pointer to
> proc. It is a "structure" with member f pointing to proc. Except
> that you may not reference member f. 

So what? You don't need the actual address of a::proc in any case. Remember
that since "func_ptr" points to a *member* function of class "a", you
should only be calling it USING AN OBJECT OF CLASS "a" (or one of its
descendants). In this case, you should be using the ->* or .* operator to
call the function.

    #include <stdio.h>

    class a {
    public:
	void proc(char *x) { printf ("a::proc: \"%s\"\n", x); }
    };

    void proc2 (void (a::*p)(char *))
    {
	a *t = new a;

	(t->*p) ("test");	// Call through pointer-to-member-function
    }

    main()
    {
	void (a::*func_ptr)(char *) = &a::proc;

	proc2 (func_ptr);
    }
-----
Shankar Unni                                   E-Mail: 
Hewlett-Packard California Language Lab.     Internet: shankar@hpda.hp.com
Phone : (408) 447-5797                           UUCP: ...!hplabs!hpda!shankar