From: Paul Janzen <pcj@xenomai.sez.to>
To: Phil Mitchell <p.mitch@gmail.com>
Cc: Xenomai Mailing List <xenomai@xenomai.org>
Subject: Re: [Xenomai] Why does mqueue.h define mqd_t as unsigned
Date: Thu, 09 Apr 2015 14:11:53 -0700 [thread overview]
Message-ID: <oqegntropy.fsf@merlin.sez.to> (raw)
In-Reply-To: <CAJZRki9RpfcQQ+c8oz1bJ7RsFQE4MrsQdULxvHAuh-STi0fhkQ@mail.gmail.com> (Phil Mitchell's message of "Thu, 9 Apr 2015 16:52:26 -0400")
Phil Mitchell <p.mitch@gmail.com> writes:
> mqueue.h defines mqd_t as an unsigned long. The function mq_open returns
> type mqd_t and states that -1 is returned in case of error.
>
> Is mqd_t defined incorrectly or am I missing something?
The man page says mq_open returns (mqd_t)(-1) on error. If you include
that cast when you test the return value it works, even if mqd_t is
unsigned. (Or a pointer.)
-- Paul
next prev parent reply other threads:[~2015-04-09 21:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-09 20:52 [Xenomai] Why does mqueue.h define mqd_t as unsigned Phil Mitchell
2015-04-09 21:07 ` Gilles Chanteperdrix
2015-04-10 18:55 ` Gilles Chanteperdrix
2015-04-09 21:11 ` Paul Janzen [this message]
2015-04-09 22:09 ` Lennart Sorensen
2015-04-09 22:17 ` Gilles Chanteperdrix
2015-04-09 22:29 ` Gilles Chanteperdrix
2015-04-09 23:17 ` Lowell Gilbert
2015-04-10 14:44 ` Lennart Sorensen
2015-04-10 14:50 ` Gilles Chanteperdrix
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