Hi, I'm trying to get a simple application up and running that sends and receives simple commands through a COM port to an Arduino hooked up to some sensors. Right now, I'm just trying to send the Arduino a simple command through a boost::asio::serial_port instance, although at some point I'll need to start reading from it as well. At any rate, I think I've got the basic premise down, but for some reason the WriteComplete function (see code below) isn't being called. After running the program, the output is: Open Sending command '.' Press any key to continue. I'm not 100% sure what's going on. The only thing I can think of is that the boost::asio::buffer(&command, sizeof(command)) statement is wrong. I'm not very familiar with these libraries, though, so I don't know what I would replace it with. I've included the code I'm using in case anyone can help me out. Thanks, -Alex --- #include "stdafx.h" #include <iostream> #include #include using namespace std; boost::asio::io_service gService; boost::asio::serial_port gPort(gService); void WriteComplete(const boost::system::error_code& error, std::size_t bytes_transferred) { cout << "Write complete." << endl; gPort.close(); } int _tmain(int argc, _TCHAR* argv[]) { gPort.open("COM3"); if(!gPort.is_open()) { cout << "Could not open com port." << endl; return 0; } cout << "Open" << endl; typedef boost::asio::serial_port_base asio_serial; gPort.set_option( asio_serial::baud_rate( 9600 ) ); gPort.set_option( asio_serial::flow_control( asio_serial::flow_control::none ) ); gPort.set_option( asio_serial::parity( asio_serial::parity::none ) ); gPort.set_option( asio_serial::stop_bits( asio_serial::stop_bits::one ) ); gPort.set_option( asio_serial::character_size( 8 ) ); char command = '.'; cout << "Sending command '" << command << "'" << endl; gPort.async_write_some( boost::asio::buffer(&command, sizeof(command)), boost::bind( &WriteComplete, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred ) ); cout << "Press any key to continue."; cin.ignore(); cin.get(); return 0; }