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From: frank_broic...@my-deja.com
Subject: System V Semphores and Linux
Date: 2000/11/29
Message-ID: <902e6n$cmk$1@nnrp1.deja.com>#1/1
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Hi,

over the last few months I developed an IPC-Library which encapsulates the
system calls needed to access semaphores, shared memory, pipes, and so on
(based on Steven's book). It is designed to support either System V or POSIX.
The basic problem is the support for Linux _and_ SGI's IRIX. IRIX is causing
no problems, but porting the Lib to Linux reveales some strange behaviour.
Basically porting the System V implementation to Linux should work, but on
some maschines it only seems to run. Getting a semphore using semget returns
a "normal" identifier and all operations on this semaphore cause no errors,
but when I look at the IPC state using ipcs then I'm told that there is no
semaphore allocated not to mention that all semaphore operations have no
effect. To top all this: on some maschines it works.

All works fine on my private maschine Suse Linux 7.0 (Kernel 2.2.16), it does
not work on a similar maschine at work and on maschines with Kernel 2.2.14
and (I know it's old) 2.0.36.

Does anybody know what is causing this strange incompatibilities?

THNX in advance

          Frank

Please reply also to: broic...@techinfo.rwth-aachen.de



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From: "Geoff Winkless" <geoff-at-farmline-dot-...@127.0.0.1>
Subject: Re: System V Semphores and Linux
Date: 2000/11/29
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<frank_broic...@my-deja.com> wrote in message
news:902e6n$cmk$1@nnrp1.deja.com...
: Hi,
:
: over the last few months I developed an IPC-Library which encapsulates the
: system calls needed to access semaphores, shared memory, pipes, and so on
: (based on Steven's book). It is designed to support either System V or
POSIX.
: The basic problem is the support for Linux _and_ SGI's IRIX. IRIX is
causing
: no problems, but porting the Lib to Linux reveales some strange behaviour.
: Basically porting the System V implementation to Linux should work, but on
: some maschines it only seems to run. Getting a semphore using semget
returns
: a "normal" identifier and all operations on this semaphore cause no
errors,
: but when I look at the IPC state using ipcs then I'm told that there is no
: semaphore allocated not to mention that all semaphore operations have no
: effect. To top all this: on some maschines it works.

Make sure you have IPC support compiled into the kernel.

Geoff