documentation/3265: man 2 open doesn't specify ENXIO from O_NONBLOCK

>Number: 3265
net
>Environment:

	System      : OpenBSD 3.2
	Architecture: OpenBSD.alpha
	Machine     : alpha

>Description:

	open(2) isn't document thoroughly. if you open a named pipe w/
	O_WRONLY|O_NONBLOCK, and there's no reader then open returns w/
	ENXIO.  however, the relevant man page doesn't specify this
	behavior.

		If the open() call would result in the process being blocked
		for some reason (e.g., waiting for carrier on a dialup
		line), open() returns immediately.

		...

		[ENXIO]	The named file is a character special or block
			special file, and the device associated with this
			special file does not exist.

>How-To-Repeat:

	if (open([fifo w/o reader],O_WRONLY|O_NONBLOCK) == -1) {
		switch(errno) {
			case ENXIO:
				err(1,"well-defined but not documented");
		}
	}

>Fix:

	Linux's man 2 page has this:

	ENXIO	O_NONBLOCK | O_WRONLY is set, the named file is a  FIFO  and
		no process has the file open for reading.  Or, the file is a
		device special file and no corresponding device exists.

>Release-Note:
Received on Mon May 19 16:30:25 2003