Re: Patch request to qt 5.9.4 (Re: [ANNOUNCEMENT] Qt 5.9.4)

[Tatsuro MATSUOKA <tmacchant2@yahoo.co.jp>]

----- Original Message -----

> From: Achim Gratz
> To: cygwin
> Cc: 
> Date: 2019/3/6, Wed 04:24
> Subject: Re: Patch request to qt 5.9.4 (Re: [ANNOUNCEMENT] Qt 5.9.4)
> 
>T atsuro MATSUOKA writes:
>>  I contacted with Enrico who tells me the patch that I have shown.
> 
> Yes, but that monkeys around the real problem.  What Yaakov is telling
> you is that there are two options and we don't know yet which one we
> have to deal with.
> 
> If O_NONBLOCK is needed, but does not work correctly under Cygwin, then
> that's a bug in Cygwin.  For this case, Corinna asks you to create an
> STC that demonstrates the bug so it can be triaged without having to
> work with something as complex as the Qt terminal in Cygwin.
> 
> If on the other hand O_NONBLOCK is in fact not needed and just shows
> different behaviour on different systems without a bug in the
> implementation being present, then upstream should remove that argument.
> 
> 
> Regards,
> Achim.

Seeing ML archive that Enrico indicated,

Re: select() and named pipes

#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;
        int count = 0;
        printf("%d: ", ++count);
        while ((status = read(fd, buf, sizeof(buf) - 1))) {
            if (status > 0) {
                buf[status] = '\0';
                printf("%s", buf);
            } else if (errno == EAGAIN) {
                    printf("\n%d: ", ++count);
            } else {
                perror("read");
                break;
            }
        }
    }

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



As you wrote this is a issue of Cygwin issue.
But As long as O_NONBLOCK does not work on Cygwin, Enrico's workaround can be attached for qt.

Tatsuro


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