Subject: RE: memcpy

[bmorris@xxxxxxxxxx]

>Date: Thu, 4 Jan 2001 07:38:07 -0600
>From: "Bartell, Aaron L. (TC)" <ALBartell@taylorcorp.com>
>
>Is there any good documentation on how to use the MEMCPY and MEMMOVE?  I
>have them in a pgm I acquired and am wondering how to get at the data that
>MEMCPY creates a pointer for(my perception).

Aaron, memcpy doesn't create a pointer.  It uses pointers that are passed
to it.

  memcpy (%addr(target), %addr(source), len)

This takes data at the location pointed to by %addr(source) and
copies to to the location pointed to by %addr(target) for a
length of "len".  The pointer it returns is just the same pointer
it was passed in the first operand; usually this value isn't needed
so memcpy is usually called just with callp.

The first 2 parameters for memcpy can be prototyped in RPG as pointers
passed by value or as other types passed by reference (including CONST).
If passed by reference, RPG would actually pass a pointer to the data.

So, the way to get at the data that memcpy moved is to look at the
first operand of memcpy.

(Everything I've said here applies to memmove too.)

The best documentation is the C runtime documentation.  Here's the
V4R3 version:
http://publib.boulder.ibm.com:80/cgi-bin/bookmgr/BOOKS/QB3AT500/1.2

Barbara Morris


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