From:	"Michael Stewart" <mike AT reggin DOT freeserve DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: 3 questions
Date:	Tue, 27 Apr 1999 07:34:23 +0100
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Ofer Nave wrote in message <7g3ia8$fhm AT dfw-ixnews10 DOT ix DOT netcom DOT com>...
>
>Jay wrote in message ...
>>I've got 3 questions to ask.
>>
>>2) How do I make a pointer to a class function and call it using that
>>pointer?
>
>This is a C++ question, not a DJGPP question, but the answer is that you
>can't take the pointer of a member function unless it is a static member
>function.  See the following:
>
>class foo
>{
>  public:
>     void myMember( void ) ;
>     static void myStaticMember( void ) ;
>} ;
>
>void main( void )
>{
>  void * ptr ;
>  foo bar ;
>
>  ptr = (void *) bar.myMember ;  // this doesn't work
>  ptr = (void *) bar.myStaticMember ;  // this works
>  ptr = (void *) foo::myStaticMember ;  // this works
>}


You can however create a function pointer to a member of the same class:

class test {
public:
   bool (*test_func) (int var); // Function pointer

   void test_func_1 (int var);
   void test_func_2 (int var);

   void choose_func (int func);
}

void test_func_1 (int var) {
   // Do stuff
}

void test_func_2 (int var) {
   // Do some more
}

void choose_func (int func) {
   if (func ==1) {
      test_func = &test_func_1;
   } else {
      test_func = &test_func_2;
   }
}


--
Michael Stewart
www.freeserve.co.uk
mike AT reggin DOT freeserve DOT co DOT uk
"Just because you're paranoid doesn't mean they aren't after you..."

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