Re: W1R2 SHM

["Chris Herborth" <chrish@qnx.com>]

What you wrote:
> [chris:]
> 
> > I've got the POSIX.4 spec here and I'm reading it (well, the bits about
> > shared memory, since I'd like W to have that ASAP even if I don't do it
> > :-)...  SysV shared memory is _similar_ to POSIX shared memory.
> 
>  I would be interested in *how* similar they are, can you point me to that
> document?

Ok, so I appear to have been wrong and they're not all that similar. 
And they're way more complex than MiNT's shared memory calls (which seem
very straight-forward).

The document is POSIX.4: Programming for the Real World byt Bill O.
Gallmeister (O'Reilly & Associates, Inc. ISBN: 1-56592-074-0).

>  Well, the first way would be to have shmat() malloc() enough memory and
> read the whole thing from the file - this will be fast (only a memcpy), but
> will take quite some memory. Shmdt() is then merely a free(). And it
> wouldn't require any particular hardware or additional support.

Yup.  I think POSIX wrappers for shared memory are going to be a little
gross though... it'd be much easier to implement it using MiNT shm
calls.  Ah well, not really that portable...C

> > If I find I'm too lazy to implement it, I'll post a summary to the MiNT
> > list so someone else can get started.  :)
> 
>  Ah, come on! :)

Kay got me all excited when he said someone had already done this for
the X port...

-- 
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Chris Herborth, R&D Technical Writer       Arcane  Dragon     chrish@qnx.com
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