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Date: Tue, 22 Dec 2009 23:43:09 +0100
From: Enrico Forestieri <forenr AT lyx DOT org>
To: cygwin AT cygwin DOT com
Subject: select() and named pipes
Message-ID: <20091222224309.GA3504@GIOVE>
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I am experiencing a problem with select() and named pipes in cygwin 1.7.
The attached test case segfaults on the select() call, but works fine
with both cygwin 1.5 and linux.

-- 
Enrico

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

#define FIFONAME "/tmp/pipe"

int main(void)
{
    int fd;
    int nsel;
    fd_set readfds;
    FD_ZERO(&readfds);

    if (mkfifo(FIFONAME, 0600) < 0) {
	perror("mkfifo");
	exit(1);
    }

    fd = open(FIFONAME, O_RDONLY | O_NONBLOCK);

    if (fd < 0) {
	perror("open");
	remove(FIFONAME);
	exit(2);
    }

    FD_SET(fd, &readfds);
    do {
	nsel = select(fd + 1, &readfds, 0, 0, 0);
    } while (nsel == -1 && (errno == EINTR || errno == EAGAIN));

    if (nsel == -1) {
	perror("select");
	exit(3);
    }

    if (FD_ISSET(fd, &readfds)) {
	char buf[100];
	int status;
	while ((status = read(fd, buf, sizeof(buf) - 1))) {
	    if (status > 0) {
		buf[status] = '\0';
		printf("%s", buf);
	    } else {
		printf("\n");
		if (errno != EAGAIN)
		    perror("read");
		break;
	    }
	}
    }

    close(fd);
    remove(FIFONAME);
    return 0;
}


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