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Date:	Wed, 26 Nov 2008 15:50:52 +0100
From:	Enrico Forestieri <forenr AT lyx DOT org>
To:	cygwin AT cygwin DOT com
Subject:	open() and named pipes
Message-ID:	<20081126145052.GB16542@sirio.sssup.it>
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According to
http://www.opengroup.org/onlinepubs/000095399/functions/open.html
the open() function shall fail and sets errno to ENXIO if
O_WRONLY | O_NONBLOCK is set, the named file is a FIFO, and no
process has the file open for reading.

This is not the case on Cygwin, as demonstrated by the attached
test case. I get "This should not happen.", while the same program
outputs "No process is reading from the other end." on both Linux
and Solaris.

-- 
Enrico

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#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define FIFONAME "/tmp/xyz.xyz"

int main(void)
{
    int fd;
    if (mkfifo(FIFONAME, 0600) < 0) {
	perror("Error");
	exit(1);
    }
    fd = open(FIFONAME, O_WRONLY | O_NONBLOCK);
    if (fd >= 0) {
	puts("This should not happen.");
	close(fd);
    } else if (errno == ENXIO) {
	puts("No process is reading from the other end.");
    }
    remove(FIFONAME);
    return 0;
}


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