void custom_sms_send_callback(vm_gsm_sms_callback_t* callback_data)
{
    if(callback_data->action == VM_GSM_SMS_ACTION_SEND)
    {
        vm_log_debug("Send SMS callback, result = %d, callback_data->result);
    }
}

void custom_sms_send(void)
{
    VMWCHAR content[100];
    VMWCHAR num[100];
    VMINT res = 0;
    vm_ascii_to_ucs2(content, 100*2, "Hello, LINKIT SMS!");
    vm_ascii_to_ucs2(num, 100*2, "10086");
    res = vm_gsm_sms_send(num, content, custom_sms_send_callback, NULL);
    if(res == 0)
    {
        vm_log_debug("Send SMS failed!");
    }
}