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From: kodiak@amiga.UUCP (Robert R. Burns)
Newsgroups: comp.sys.amiga
Subject: Re: clipboard.device question - does it support random writes?
Message-ID: <1964@amiga.amiga.UUCP>
Date: Tue, 10-Nov-87 23:19:16 EST
Article-I.D.: amiga.1964
Posted: Tue Nov 10 23:19:16 1987
Date-Received: Fri, 13-Nov-87 20:38:04 EST
References: <562@radio.toronto.edu>
Reply-To: kodiak@amiga.UUCP (Robert R. Burns)
Organization: Commodore-Amiga Inc., 16795 Lark Ave. Suite 106, Los Gatos CA 95030
Lines: 20

Chris Siebenmann writes:
> I'm working on an application that I'd like to support the clipboard.
>Unfortunately, the clipboard.device wants data in IFF format, and
>writing IFF-format data really needs something that supports writes at
>random offsets. The documentation for the clipboard.device hints that
>you can do this by playing with the io_Offset field (indeed, it hints
>at having a Seek() call of some sort), but I'd like to be sure before
>I start writing a lot of code.

Yea! (ambiguous: yes, enthusiam).  Realize that the clipboard.device
is an Exec style device, and is thus written to with a variant of the
IORequest structure (IOClipReq in libraries/clipboard.h) using
SendIO/DoIOish code.  In the IOClipReq there is an io_Offset field
that after a Write (CMD_WRITE) points to the "next" position, but you
can set it to any value you want before a Write (i.e. Seek)

The clipboard.device tries to keep things in ram, but if ram runs low
it puts the clip in the file DEVS:clipboards/0 (which is the intended
place to exchange data: other units besides 0 are available, though)

- Kodiak