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  • io/wait/wait.c

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IO

Public Instance Methods

nread → int click to toggle source

Returns number of bytes that can be read without blocking. Returns zero if no information available.

 
               static VALUE
io_nread(VALUE io)
{
    rb_io_t *fptr;
    int len;
    ioctl_arg n;

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    len = rb_io_read_pending(fptr);
    if (len > 0) return len;
    if (!FIONREAD_POSSIBLE_P(fptr->fd)) return INT2FIX(0);
    if (ioctl(fptr->fd, FIONREAD, &n)) return INT2FIX(0);
    if (n > 0) return ioctl_arg2num(n);
    return INT2FIX(0);
}
            
ready? → true, false or nil click to toggle source

Returns true if input available without blocking, or false. Returns nil if no information available.

 
               static VALUE
io_ready_p(VALUE io)
{
    rb_io_t *fptr;
    ioctl_arg n;

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    if (rb_io_read_pending(fptr)) return Qtrue;
    if (!FIONREAD_POSSIBLE_P(fptr->fd)) return Qnil;
    if (ioctl(fptr->fd, FIONREAD, &n)) return Qnil;
    if (n > 0) return Qtrue;
    return Qfalse;
}
            
wait → IO, true, false or nil click to toggle source
wait(timeout) → IO, true, false or nil

Waits until input is available or times out and returns self or nil when EOF is reached.

 
               static VALUE
io_wait(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr;
    struct wait_readable_arg arg;
    int fd, i;
    ioctl_arg n;
    VALUE timeout;
    struct timeval timerec;

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    rb_scan_args(argc, argv, "01", &timeout);
    if (NIL_P(timeout)) {
        arg.timeout = 0;
    }
    else {
        timerec = rb_time_interval(timeout);
        arg.timeout = &timerec;
    }

    if (rb_io_read_pending(fptr)) return Qtrue;
    if (!FIONREAD_POSSIBLE_P(fptr->fd)) return Qfalse;
    fd = fptr->fd;
    rb_fd_init(&arg.fds);
    rb_fd_set(fd, &arg.fds);
#ifdef HAVE_RB_FD_INIT
    i = (int)rb_ensure(wait_readable, (VALUE)&arg,
                       (VALUE (*)_((VALUE)))rb_fd_term, (VALUE)&arg.fds);
#else
    i = rb_thread_select(fd + 1, rb_fd_ptr(&arg.fds), NULL, NULL, arg.timeout);
#endif
    if (i < 0)
        rb_sys_fail(0);
    rb_io_check_closed(fptr);
    if (ioctl(fptr->fd, FIONREAD, &n)) rb_sys_fail(0);
    if (n > 0) return io;
    return Qnil;
}