File content as of revision 1:8a46a714f75d:

#include "mbed.h"
#include "GSwifi.h"

#define SERVER  "mail.example.com"
#define PORT    587   // 25
#define TO      "to@example.com"
#define FROM    "from@example.com"
#define SUBJECT "TEST"
#define MESG    "Hello!\r\n"
#define USER    "username"  // SMTP Auth
#define PWD     "password"  // SMTP Auth

#define SECURE GSSEC_WPA_PSK
#define SSID "SSID"
#define PASS "passkey"

GSwifi gs(p13, p14); // TX, RX (no flow control)
// GSwifi gs(p13, p14, p12, P0_22); // TX, RX, CTS, RTS

Serial pc(USBTX, USBRX);
DigitalOut led1(LED1), led2(LED2);

int main () {
    IpAddr ipaddr, netmask, gateway, nameserver;
    Host host;

    led1 = 1;
    pc.baud(115200);

    pc.printf("connect\r\n");
    if (gs.connect(SECURE, SSID, PASS)) {
        return -1;
    }
    gs.getAddress(ipaddr, netmask, gateway, nameserver);
    pc.printf("ip %d.%d.%d.%d\r\n", ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);

    led2 = 1;
    pc.printf("sendmail\r\n");
    host.setName(SERVER);
    host.setPort(PORT);
//    gs.mail(host, TO, FROM, SUBJECT, MESG);  // no auth
    gs.mail(host, TO, FROM, SUBJECT, MESG, USER, PWD);  // SMTP auth

    for (;;) {
        gs.poll();

        wait_ms(50);
        led1 = !led1;
        led2 = 0;
    }
}