From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Thu, 17 Apr 2008 13:04:17 +0200
From: Sebastian Smolorz <smolorz@domain.hid>
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Subject: Re: [Xenomai-help] RTDM question
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To: Bosko Radivojevic <bosko.radivojevic@domain.hid>
Cc: xenomai-help <xenomai@xenomai.org>

Bosko Radivojevic wrote:
> What could be the reason of rt_dev_open() returning 0 (zero)?
> 
> I can see that device is properly registered. When I start user-space
> program, I can see in /proc/xenomai/rtdm/filedes that one file is
> open:
> Index   Locked  Device          Owner [PID]
> 0       0       macbdev0        user [306]
> 
> But I never reach write function. rt_dev_write() & rt_dev_read() are
> returning -1.

Which read and write handlers do you have registered with your device 
(RT/NRT)? From which context do you call the RTDM functions 
(primary/secondary)?

  In API documentation, for rt_dev_open return values
> says:
> Positive file descriptor value on success, otherwise a negative error code.

I think this is a bug in the documentation. Negative values mean errors, 
all other values (including zero) success.

-- 
Sebastian