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);
}
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;
}
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;
}