File content as of revision 7:1720ab8fec13:

/*
 * TcpClient example using the UIPEthernet library for ENC28J60 Ethernet boards.
 *
 */
#include "mbed.h"
#include "UipEthernet.h"
#include "TcpClient.h"

#define IP      "192.168.1.35"
#define GATEWAY "192.168.1.1"
#define NETMASK "255.255.255.0"

const uint8_t   MAC[6] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 };
UipEthernet     net(MAC, D11, D12, D13, D10);   // mac, mosi, miso, sck, cs

/**
 * @brief
 * @note
 * @param
 * @retval
 */
int main()
{
    const time_t    TIMEOUT = 5;    // Connection timeout time
    time_t          timeOut;
    char            data[] = "GET / HTTP/1.1\r\nHost: ifconfig.io\r\nConnection: close\r\n\r\n";
    char*           remaining;
    uint8_t*        recvBuf;
    int             result;

    printf("Starting ...\r\n");

    //net.set_network(IP, NETMASK, GATEWAY);  // include this to use static IP address
    net.connect();

    // Show the network address
    const char*     ip = net.get_ip_address();
    const char*     netmask = net.get_netmask();
    const char*     gateway = net.get_gateway();
    printf("IP address: %s\n", ip ? ip : "None");
    printf("Netmask: %s\n", netmask ? netmask : "None");
    printf("Gateway: %s\n", gateway ? gateway : "None");

    // Open a socket on the network interface, and create a TCP connection to ifconfig.io
    TcpClient   socket;

    result = socket.open(&net);
    if (result != 0) {
        printf("Error! socket.open() returned: %d\n", result);
    }

    timeOut = time(NULL) + TIMEOUT;
    printf("Connecting to the 'ifconfig.io' server ...\r\n");

    result = socket.connect("ifconfig.io", 80);
    if (result != 0) {
        printf("Error! socket.connect() returned: %d\n", result);
        goto DISCONNECT;
    }

    printf("Server connected.\r\n");
    printf("Sending data to server:\r\n");
    remaining = data;
    result = strlen(remaining);
    while (result) {
        result = socket.send((uint8_t*)remaining, strlen(remaining));
        if (result < 0) {
            printf("Error! socket.send() returned: %d\n", result);
            goto DISCONNECT;
        }
        printf("%.*s", result, remaining);
        remaining += result;
    }

    printf("Waiting for data from server:\r\n");
    while (socket.available() == 0) {
        if (time(NULL) > timeOut) {
            printf("Connection time out.\r\n");
            goto DISCONNECT;
        }
    }

    printf("Data received:\r\n");
    while ((result = socket.available()) > 0) {
        recvBuf = (uint8_t*)malloc(result);
        result = socket.recv(recvBuf, result);
        if (result < 0) {
            printf("Error! socket.recv() returned: %d\n", result);
            goto DISCONNECT;
        }
        printf("%.*s\r\n", result, recvBuf);
        free(recvBuf);
    }

    printf("\r\n");

DISCONNECT:
    // Close the socket to return its memory and bring down the network interface
    socket.close();

    // Bring down the ethernet interface
    net.disconnect();
    printf("Done\n");
}