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Date: Mon, 13 Sep 2010 13:57:03 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-help] rt_queue_read and EPERM?
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To: =?UTF-8?B?SmVucyBLw7ZobGVy?= <jenskxxx@domain.hid>
Cc: xenomai@xenomai.org

Jens K=C3=B6hler wrote:
> Hello Gilles,
> =20
> here is the code:
> =20
> RT_QUEUE myqueue;
> int retval;
> retval =3D rt_queue_create(&myqueue, "myqueue", 255, 10, Q_FIFO);
> =20
> char message[100] =3D "Message ";
> retval =3D rt_queue_write(&myqueue,message,sizeof(message),Q_NORMAL);
> //retval is 0
> =20
> char msgBuf[255];
> retval =3D rt_queue_read(&myqueue, msgBuf, sizeof(msgBuf), TM_NONBLOCK)=
;
> //retval is always -1, why?

Probably because the callling thread is not a Xenomai thread, it is a
simple Linux thread, and as such, is not allowed to switch to primary
mode as is required by rt_queue_read.

--=20
					    Gilles.