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From: asc@concurrent.co.uk (Andy Chittenden)
Newsgroups: comp.lang.c++
Subject: pointers to member functions
Message-ID: <950@sl10c.concurrent.co.uk>
Date: 1 Dec 89 08:00:19 GMT
Sender: info@concurrent.co.uk
Reply-To: asc@concurrent.co.uk (Andy Chittenden)
Organization: Concurrent Computer Corp (ESDG), Slough, U.K.
Lines: 32

// We are using pointers to member functions with version 1.2.  Below is
// cut down example.  This compiles fine under version 1.2 but doesn't
// under version 2.

class base {
  public:
    int fn1(int p);
};

class derived : public base {
  public:
    int fn2(int p);
};

typedef int (base::*EH_function) (int);
class dispatcher {
  public:
    dispatcher(EH_function p);
};

main()
{
	dispatcher a(base::fn1);
	dispatcher b(derived::fn2);	// fails to compile under v2
}

// I can understand why the second line does not compile (derived::fn2
// is not a function of base).  However, how is one meant to achieve the
// above effect under v2 (pass an arbitrary function of a derived class
// with matching parameters)?

Thanks in anticipation, Andy Chittenden