Inherited from posix::descriptor_base.

IO control command to get the amount of data that can be read without blocking.

typedef implementation_defined bytes_readable;

Implements the FIONREAD IO control command.

Example

boost::asio::posix::stream_descriptor descriptor(io_service); 
...
boost::asio::descriptor_base::bytes_readable command(true);
descriptor.io_control(command);
std::size_t bytes_readable = command.get();