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To: Bruce Evans <bde@zeta.org.au>
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Subject: Re: cvs commit: src/usr.sbin/sysinstall command.c config.c 
In-reply-to: Your message of "Sun, 23 Sep 2001 18:06:02 +1000."
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Date: Sun, 23 Sep 2001 10:49:28 -0700
From: Bakul Shah <bakul@bitblocks.com>
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> >     Use '%p' when printing out the address of a function.
> >     sizeof(int) != sizeof(long)
> 
> %p is for printing pointers of type "void *".  It is unsuitable for
> printing arbitrary pointers to objects.  It is especially unsuitable
> for printing pointers to functions.

I have an old (1997) working draft of C9X which says

    6.2.2.3  Pointers

	   [#1] A pointer to void may be converted to or from a pointer
	   to  any  incomplete  or  object  type.   A  pointer  to  any
	   incomplete or object type may be converted to a  pointer  to
	   void  and  back again; the result shall compare equal to the
	   original pointer.

Since any object ptr may be converted to %p, you can do, e.g.

	printf("...%p...", ..., (void*)&some_function, ...);

But you seem to be saying this is not be a valid conversion.
Have things changed since then or is a function not
considered an "object"?  I would appreciate a C standard
reference ( i.e. chapter and verse!) that shows this is
invalid.

At any rate %p is preferable to %x or %lx even if not
properly pedantic.  I have used machines with segmented
address space (an NEC unix machine in mid80s though I forget
the model number) where %p would give you <seg>:<addr> but %x
or %lx would be wrong.

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