End of Life Ruby 3.0 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

IO#wait_readable

io.wait_readable → true or false

io.wait_readable(timeout) → true or false

static VALUE
io_wait_readable(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr = NULL;

    RB_IO_POINTER(io, fptr);
    rb_io_check_readable(fptr);

    if (rb_io_read_pending(fptr)) return Qtrue;

    rb_check_arity(argc, 0, 1);
    VALUE timeout = (argc == 1 ? argv[0] : Qnil);

    return io_wait_event(io, RUBY_IO_READABLE, timeout);
}

Waits until IO is readable and returns true, or false when times out. Returns true immediately when buffered data is available.

Ruby version changes

3.0
- IO#wait_readable, IO#wait_writable, IO#read, IO#write and other related methods (e.g. IO#puts, IO#gets) may invoke the scheduler hook io_wait(io, events, timeout) in a non-blocking execution context. [Feature #16786]

See also #wait_priority #wait_writable #wait #winsize also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.1

‹ prev#wait_priority next ›#wait_writable