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From: hopper@ux.acs.umn.edu (hopper)
Newsgroups: comp.lang.c++
Subject: Re: Turbo-C++ catch, template, .* , ->*
Message-ID: <2151@ux.acs.umn.edu>
Date: 28 Aug 90 21:46:23 GMT
References: <AHUTTUNE.90Aug28211112@silver-surfer.hut.fi>
Reply-To: hopper@ux.acs.umn.edu (Eric Hopper)
Distribution: comp
Organization: Omnifarious Software
Lines: 69

In article <AHUTTUNE.90Aug28211112@silver-surfer.hut.fi> ahuttune@niksula.hut.fi (Ari Juhani Huttunen) writes:
>
>I found something strange in TC++ documentation recently. The keywords
>and operatators mentioned in the header of this article are mentioned
>in "Turbo C++ Programmer's Guide", but NOWHERE is there any explanation
>for them.. At least I couldn't find any.
>
>So, what are operators
>	.*
>	->*
>and keywords
>	catch
>	template

	I've never heard of those keywords, but the operators are documented
in the Turbo C++ online manual. They may be in the paper manual too, but I
don't look at that a lot. It doesn't provide a complete enough definition
for me.

	The operators .* and ->* are pointer-to-member referencing
operators. C++ has provided a way to get offset pointers into a class, the
best way to explain it is an example.

(Note: This was gotten from 'Programming In C++' by Stephen C. Dewhurst &
Kathy T. Stark, part of the Prentice Hall Software Series, a book I kinda
like.)

class Node {
 public:
   int code;
   int num;
   void print();
   void report();
};

SomeSillyFunction(Node &n, int Node::*pi)
{
   *np = &n;
   int i, j;

   i = n.*pi;
   j = np->*pi;
}

main()
{
   Node n;

   SomeSillyFunction(n, &(Node::num)); // Both i & j get set to n.num
   SomeSillyFunction(n, &(Node::code)); // Both i & j get set to n.code
}

	I presume that this construct would be most useful when offset
pointers to functions. It is the only reliable way to get the address of a
member function, since they have to have a this pointer passed to them.

Have fun,
UUCP: rutgers!umn-cs!ux.acs.umn.edu!hopper   (Eric Hopper)
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