Date: Sun, 18 Feb 2001 16:17:29 -0700 From: Drew Eckhardt <drew@PoohSticks.ORG> To: David Rufino <daverufino@btinternet.com> Cc: hackers@FreeBSD.ORG Subject: Re: character device driver Message-ID: <200102182317.f1INHTn24123@chopper.Poohsticks.ORG> In-Reply-To: Your message of "Tue, 13 Feb 2001 19:31:50 GMT." <20010213193150.A882@btinternet.com>
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In message <20010213193150.A882@btinternet.com>, daverufino@btinternet.com writ es: >Hi, > >I'm writing a character device driver in which each minor device can be >opened more than once. When a device is opened is there a way to associate >some private data for each opened instance ? As other people have noted, not in the general case. The solution I've used is to split the device minor number into a physical unit and open instance part. You keep the existing per-unit structure, and add per-instance data including a busy flag which causes opens to return EBUSY. In your user land application, you iterate over the devices in round-robin fashion as long as you get back EBUSY as you would for pty masters. -- <a href="http://www.poohsticks.org/drew/">Home Page</a> For those who do, no explanation is necessary. For those who don't, no explanation is possible. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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