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From: valdis.kletnieks@vt.edu
To: noloader@gmail.com
Cc: kernelnewbies <kernelnewbies@kernelnewbies.org>
Subject: Re: How to make /dev/ttyACM0 (and friends) exclusive?
Date: Sat, 02 Mar 2019 13:45:33 -0500	[thread overview]
Message-ID: <3824.1551552333@turing-police> (raw)
In-Reply-To: <CAH8yC8kY5Dnxpxwy-CoRcAT-spuAz+eQ7haKY1ACR02tKqy7_w@mail.gmail.com>

On Fri, 01 Mar 2019 23:29:53 -0500, Jeffrey Walton said:

> I cannot seem to open the device in exclusive mode. The current open
> is (I also tried with O_EXCL):
>
>     int modem = open(device_path, O_RDWR | O_NOCTTY | O_SYNC);

So what happens?  Does the open fail? If so, what does perror() say about it?
Or does the open work but the flag is ignored?

Have you tried making the *other* program open it with O_EXCL so your
caller-id program can't mess with its state?

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  parent reply	other threads:[~2019-03-02 18:47 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-02  4:29 How to make /dev/ttyACM0 (and friends) exclusive? Jeffrey Walton
2019-03-02  7:50 ` Greg KH
2019-03-02 18:45 ` valdis.kletnieks [this message]
2019-03-02 19:36   ` Jeffrey Walton
2019-03-03  5:55     ` valdis.kletnieks
2019-03-03  8:55       ` Jeffrey Walton
2019-03-03 11:00         ` Greg KH
2019-03-04 13:04           ` Jeffrey Walton
2019-03-04 13:20             ` Greg KH
2019-03-04 15:38             ` Yann Droneaud
2019-03-04 22:01               ` valdis.kletnieks
2020-10-06 20:41                 ` Daniel Santos
2020-10-11 14:52                   ` linux lover

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