[vorbis-dev] ogg123 doesn't destroy shm segment

[Kenneth Arnold]

On Sat, Mar 17, 2001 at 02:49:15PM +0000, Christian Weisgerber wrote:
> Every time ogg123 -bXXX is run, it creates another shared memory
> segment but fails to destroy it on exit.  Thus an increasing number
> of shm segments keeps piling up and eat all the (often rather
> limited amount of) available shared memory.
> 
> The patch below corrects this and also fixes the bizarre abuse of
> stat() permission bits for shmget().

I stole some of that shm code from buffer(1). I need to go back and
steal some more :) Well okay I didn't "steal" it per se, just used it
as an example of how to use the Unix shm functions.

> On systems that support it, I'd very much like to get rid of using
> SYSVSHM altogether and instead use a shared memory mapping of
> /dev/zero.  The code is very simple and I have it running on BSD,
> but I still need to steal an autoconf fragment to test for availability
> of this feature in a portable manner.  More on this later.

I was aware of this solution, and indeed it does seem cleaner. However
I still do not know how portable this method is. Anyone?

> -			  IPC_CREAT|S_IREAD|S_IWRITE);
> +			  IPC_CREAT|SHM_R|SHM_W);

duh. Those weren't in my manpage, though, IIRC.

> +  /* Remove segment after last process detaches it or terminates. */
> +  shmctl(shmid, IPC_RMID, 0);
> +

ure. But wait a second -- a shared memory segment stays around even
after the last process using it dies? Sounds like Win32...

Patch will be applied as soon as I copy it over from my server,
test-compile and commit. Oops, gotta switch out my mobo now...


-- 
Kenneth Arnold <ken at arnoldnet.net> / kcarnold / Linux user #180115
http://arnoldnet.net/~kcarnold/



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