From: Dave Bird <dave AT xemu DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Pointers to functions.
Date: Sun, 7 Mar 1999 18:18:30 +0000
Organization: very little
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In ar<7bu8hk$6b6$1 AT camel19 DOT mindspring DOT com>, Lark <rlark AT at DOT mbhs> writes
>
>What is the purpose(point, if you will) of having a pointer to a function?

 so that a 'C' variable can indicate a 'variable' sort of function
 i.e. a different actual function to be used in different contexts.

 For example:

 You might want to write a clever sort algorithm which can sort many
 different kinds of data. Let's assume it can cope correctly with
 the varying lengths of data and find the next record all right.

 Then you might have a parameter which was  int (*compare)();
 i.e. what compare points at is a function that returns int
 being -1 0 +1 for less or equal or greater.  Of course it
 would be a different function depending on whether the objects
 you were sorting were strings, 128bit integers, polygons, 
 or whatever.



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