From owner-freebsd-hackers  Sun Sep  5 22:48:32 1999
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Date: Mon, 6 Sep 1999 09:47:32 +0400 (MSD)
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From: Alex Povolotsky <tarkhil@asteroid.svib.ru>
To: stable@freebsd.org
Cc: hackers@freebsd.org
Subject: Problems with FIFO open in non-blocking mode?
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Hello!

The following program

#include <stdio.h>
#include <fcntl.h>

main() {
	int control;
	if ((control = open("STATUS",O_WRONLY|O_NONBLOCK))<0) {
		perror("Could not open STATUS ");
		exit(1);
	}
	printf("STATUS ready\n");
	close(control);
	return(0);
}

fails to run (STATUS is pre-created FIFO file) with error "Device not
configured", which seems kinda odd for me.

However, when FIFO is opened with O_RDWR and O_NONBLOCK, every attempt 
to select(2) its handler for writing doesn't wait until someone opens
FIFO for reading, but instead FIFO is ready to write at every select.

Is it a bug or a feature?

-- 
Alexander B. Povolotsky                            [ICQ 18277558]
[2:5020/145]  [http://freebsd.svib.ru] [tarkhil@asteroid.svib.ru]


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