endPacket() failure - Githubissues

I'm writing a quite complex sketch where I use Ethernet library to provide UDP bidirectional connections between a Teensy + W850io module and a client application running on an Android tablet. The 'receving' part (running on Teensy) works fine but when I try to send data back to the client I got a very strange behaviour on endPacket() call. Everything stops working just after this call..

This's my code:

void sendTelemetry(int i, const char* _identification, int _value)
{
  char _buffer[5] = { 0, 0, 0, 0, 0 };
  char _buffer_crc[3] = { 0, 0, 0 };
  char _buffer_identification[2] = { 0, 0 };
  String _aux = "";
  byte _crc = 0x00;

  _aux.reserve(16);

  Int2HexStr(_value, _buffer);
  _crc = computeCRC(_buffer);                   // TODO: calcolo crc
  Byte2HexStr(_crc, _buffer_crc);                // sprint(_buffer_crc,"%02X", _crc );

#ifdef DEBUG_SEND_TELEMETRY
  Serial.print("CRC(0x)=");
  Serial.println(_buffer_crc);
#endif

  sprintf(_buffer_identification, "%d", i);

  _aux = "$";
  _aux += _identification;
  _aux += _buffer_identification;
  _aux += _buffer;
  _aux += _buffer_crc;
  _aux += "&";

  if (ethTelemetry.beginPacket(destinationIP, UDP_REMOTE_PORT) == 1)
  {
    ethTelemetry.write(_aux.c_str());
#ifdef DEBUG_SEND_TELEMETRY
    Serial.print("UDP sending: ");
#endif

    if (ethTelemetry.endPacket() != 1)
    {
#ifdef DEBUG_SEND_TELEMETRY
      Serial.print("endPacket() failed!");
#endif
    }
  }
  else
  {
#ifdef DEBUG_SEND_TELEMETRY
    Serial.print("beginPacket() failed!");
#endif
  }

#ifdef DEBUG_SEND_TELEMETRY
  Serial.print("...sent: ");
  Serial.println(_aux.c_str());
#endif
}

PaulStoffregen / Ethernet

endPacket() failure #29