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From: "Andrej Borsenkow" <Andrej DOT Borsenkow AT mow DOT siemens DOT ru>
To: <cygwin AT sourceware DOT cygnus DOT com>
Subject: Problems with pty under Cygwin
Date: Fri, 7 Jul 2000 13:39:54 +0400
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In-Reply-To: <200007041321.JAA15692@envy.delorie.com>

A program opens pty and starts external command attached to the slave
side. Parent reads from master side a character at a time in
non-blocking mode. The problem is, parent gets EOF (read() returns zero)
after every line of child output.

The pty is opened with:

static int
get_pty(int master, int *retfd)
{
    static char *name;
    static int mfd, sfd;

    int ret;

    if (master) {
        if ((mfd = open("/dev/ptmx", O_RDWR)) < 0)
            return 1;

        if (grantpt(mfd) || unlockpt(mfd) || !(name = ptsname(mfd))) {
            close(mfd);
            return 1;
        }
        *retfd = mfd;

        return 0;
    }
    if ((sfd = open(name, O_RDWR)) < 0) {
        close(mfd);
        return 1;
    }

    *retfd = sfd;

    return 0;
}


It is based on API list that mentions grantpt() & Co.

What do I do wrong? The same program runs fine on Unix returning full
child output.

-andrej


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