pipe2

fn pipe2(flags: c.O) PipeError![2]c.fd_t {
    var fds: [2]c.fd_t = undefined;

    while (true) switch (c.errno(c.pipe(&fds))) {
        .SUCCESS => break,
        .INTR => {},
        .NFILE => return error.SystemFdQuotaExceeded,
        .MFILE => return error.ProcessFdQuotaExceeded,
        else => |err| return unexpectedErrno(err),
    };
    errdefer {
        closeFd(fds[0]);
        closeFd(fds[1]);
    }

    // https://github.com/ziglang/zig/issues/18882
    if (@as(u32, @bitCast(flags)) == 0) return fds;

    // CLOEXEC is special, it's a file descriptor flag and must be set using
    // F.SETFD.
    if (flags.CLOEXEC) for (fds) |fd| while (true) switch (c.errno(c.fcntl(fd, c.F.SETFD, @as(u32, c.FD_CLOEXEC)))) {
        .SUCCESS => break,
        .INTR => {},
        else => |err| return unexpectedErrno(err),
    };

    const new_flags: u32 = f: {
        var new_flags = flags;
        new_flags.CLOEXEC = false;
        break :f @bitCast(new_flags);
    };

    // Set every other flag affecting the file status using F.SETFL.
    if (new_flags != 0) for (fds) |fd| while (true) switch (c.errno(c.fcntl(fd, c.F.SETFL, new_flags))) {
        .SUCCESS => break,
        .INTR => {},
        .INVAL => |err| return errnoBug(err),
        else => |err| return unexpectedErrno(err),
    };

    return fds;
}