🚀 go-pugleaf

On 11 Apr 90 10:34:19 GMT, mapjilg@bath.ac.uk (J I L Gold) said:

mapjilg> OK, now I know what these are, what is a CPTR ?

From <exec/types.h>:
--
typedef unsigned long	ULONG;	    /* unsigned 32-bit quantity */
typedef unsigned char	*STRPTR;    /* string pointer */
typedef STRPTR		*APTR;	    /* absolute memory pointer */

/* sigh.  APTR was misdefined, but compatibility rules.	 Heres what it
 * should have been
 */
typedef ULONG		CPTR;	    /* absolute memory pointer */

typedef unsigned char	TEXT;
--

So, as you can see, CPTR is a "fixed" APTR typedef.  Unfortunately, it
is still misdefined.  Properly, APTR should be defined as:

typedef VOID            *APTR;      /* absolute memory pointer */

which is a generic pointer.  The original APTR ended up being an
unsigned char **, which is clearly wrong.  The "fixed" CPTR is an
unsigned long, which is actually worse, since APTR is at least a
pointer.  (just a pointer to a pointer)  CPTR is not a pointer, so if
the pointers in the machine were, say, 64 bits, a CPTR would be the
wrong size, but an APTR would not.

All of this is somewhat academic at this point, since all three forms
work within the present architecture -- they all resolve to a 4-byte
(longword) value.  Still, both "official" definitions are wrong.

*sigh*

Deven
-- 
Deven T. Corzine        Internet:  deven@rpi.edu, shadow@pawl.rpi.edu
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