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From: comeau@ditka.Chicago.COM (Greg Comeau)
Newsgroups: comp.lang.c++,comp.lang.c
Subject: Re: Pointers to functions
Message-ID: <39059@ditka.Chicago.COM>
Date: 17 May 91 05:17:58 GMT
References: <AJ3U.91May14140642@wilbury.cs.virginia.edu>
Sender: comeau@ditka.Chicago.COM (Greg Comeau)
Reply-To: comeau@csanta.attmail.com (Greg Comeau)
Followup-To: comp.lang.c++
Organization: Comeau Computing
Lines: 26

In article <AJ3U.91May14140642@wilbury.cs.virginia.edu> aj3u@wilbury.cs.virginia.edu (Asim Jalis) writes:
>pf = hello;	and     pf = &hello;
>The definitions for pf and hello are as follows:
>void (*pf)();	// pointer to a function
>void hello() {   printf("Hello World\n"); }
>I used the two different forms of assignments and got the same output.
>Is there a difference between them?

There is a difference even though they both end up at the same.

In 'pf = hello;', the function name expression is implicitly converted into
a pointer to a function of the appropriate type (a void(*)()) when in this
context.

With 'pf = &hello;', since the operand of & is a function, it is a pointer
to a function of the appropriate type.  It does not become a pointer to a
pointer to a function.

The C++ style is to use the & form.

- Greg
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