#include "mbed.h"
#include "EthernetInterface.h"
const char* SERVER_ADDRESS = "192.168.1.200";
const int SERVER_PORT = 55555;
const bool CHECK_RESPONSE = true;

int main()
{
    EthernetInterface eth; // declare interface
    eth.init(); // initialize interface to use DHCP
    eth.connect(); // connect interface
    printf("\nIP Address aquired: %s\n", eth.getIPAddress()); // display IP address
    TCPSocketConnection client; // set up a client socket
    client.set_blocking(false,10); // limit client to a 10ms wait for response
    if(!client.connect(SERVER_ADDRESS, SERVER_PORT)) // connect to server
    {
        printf ("Connected to Server\n");
        char message[] = "Hello";
        char response[256];
        int bytes_sent;
        int bytes_received;
        int loop;
        for (loop=0;loop<100;loop++)
        {
            // send data
            bytes_sent = client.send_all(message, strlen(message)); 
            printf("Sent: %d '%s' (Bytes: %d)\n",loop,message,bytes_sent);
            // check for received data
            if(CHECK_RESPONSE)
            {
                bytes_received = client.receive(response, 256);
                if (bytes_received!=-1)
                {
                    response[bytes_received] = '\0';
                    printf("Received: '%s' (Bytes: %d)\n",response, bytes_received);
                }
            }
        }
    }
    else
    {
        printf("Unable to connect to server\n");
    }
    printf("Finished\n");
}

Hi, I have been trying for a couple of weeks to create an mbed client that sends data over a TCP connection to a server. I have finally been able to get this working but I believe this has identified a bug as the behaviour is not as I expected. My goal was to connect the client to a server and send data from the client only. To re-create the unexpected behaviour, you need the code from this post for the mbed client and a working TCP server on which you can turn ECHO on and off. Scenarios: MBED (CHECK_RESPONSE = false) : SERVER (ECHO = ON or OFF): The mbed will send about 5 messages and then hang. MBED (CHECK_RESPONSE = true) : SERVER (ECHO = OFF): The mbed will complete the loop, but only actually send about 20 messages. MBED (CHECK_RESPONSE = true) : SERVER (ECHO = ON): This is completely successful, the mbed sends all data and the server receives all data. I expected to be able to send data from the client for the server to process without any need for the server to send any data back. I am sorry, but identifying the bug itself is way above my level, but I do believe that there is a problem somewhere with the libraries. Regards, Arthur <<code>> #include "mbed.h" #include "EthernetInterface.h" const char* SERVER_ADDRESS = "192.168.1.200"; const int SERVER_PORT = 55555; const bool CHECK_RESPONSE = true; int main() { EthernetInterface eth; // declare interface eth.init(); // initialize interface to use DHCP eth.connect(); // connect interface printf("\nIP Address aquired: %s\n", eth.getIPAddress()); // display IP address TCPSocketConnection client; // set up a client socket client.set_blocking(false,10); // limit client to a 10ms wait for response if(!client.connect(SERVER_ADDRESS, SERVER_PORT)) // connect to server { printf ("Connected to Server\n"); char message[] = "Hello"; char response[256]; int bytes_sent; int bytes_received; int loop; for (loop=0;loop<100;loop++) { // send data bytes_sent = client.send_all(message, strlen(message)); printf("Sent: %d '%s' (Bytes: %d)\n",loop,message,bytes_sent); // check for received data if(CHECK_RESPONSE) { bytes_received = client.receive(response, 256); if (bytes_received!=-1) { response[bytes_received] = '\0'; printf("Received: '%s' (Bytes: %d)\n",response, bytes_received); } } } } else { printf("Unable to connect to server\n"); } printf("Finished\n"); } <</code>>