No Matching Function Begin Multicast - Arduino/cpp

Question

I was given a project to convert from ESP8266 to ESP32, and I'm definitely not a coder, but it needs to get done. So I was hoping I could get some guidance/help on how to solve this issue. I'm basically taking previous code from an old project using an ESP8266 WiFi module and converting it over to a more updated module using ESP32. Been compiling and troubleshooting code as I go the best I can, but this one has stumped me.

The error message I'm getting is "No matching function for call to 'WiFiUDP::beginMulticast(IPAddress, IPAddress&, const unsigned int&)'

There are several pages of code, but this is the.cpp file that is currently throwing up an error, and hoping it's able to be resolved with something on this page. Like I said, I'm not a coder, but I have the basics down. Any help on this would be greatly appreciated. Thanks!

#include "Switch.h"
#include <functional>
 
// Multicast declarations
IPAddress ipMulti(239, 255, 255, 250);
const unsigned int portMulti = 1900;
char packetBuffer[512];   

#define MAX_SWITCHES 14
Switch switches[MAX_SWITCHES] = {};
int numOfSwitchs = 0;

//#define numOfSwitchs (sizeof(switches)/sizeof(Switch)) //array size  
 
//<<constructor>>
UpnpBroadcastResponder::UpnpBroadcastResponder(){
    
}
 
//<<destructor>>
UpnpBroadcastResponder::~UpnpBroadcastResponder(){/*nothing to destruct*/}
 
bool UpnpBroadcastResponder::beginUdpMulticast(){
  boolean state = false;
  
  Serial.println("Begin multicast ..");
  
  if(UDP.beginMulticast(WiFi.localIP(), ipMulti, portMulti)) {
    Serial.print("Udp multicast server started at ");
    Serial.print(ipMulti);
    Serial.print(":");
    Serial.println(portMulti);

    state = true;
  }
  else{
    Serial.println("Connection failed");
  }
  
  return state;
}

//Switch *ptrArray;

void UpnpBroadcastResponder::addDevice(Switch& device) {
  Serial.print("Adding switch : ");
  Serial.print(device.getAlexaInvokeName());
  Serial.print(" index : ");
  Serial.println(numOfSwitchs);
  
  switches[numOfSwitchs] = device;
  numOfSwitchs++;
}

void UpnpBroadcastResponder::serverLoop(){
  int packetSize = UDP.parsePacket();
  if (packetSize <= 0)
    return;
  
  IPAddress senderIP = UDP.remoteIP();
  unsigned int senderPort = UDP.remotePort();
  
  // read the packet into the buffer
  UDP.read(packetBuffer, packetSize);
  
  // check if this is a M-SEARCH for WeMo device
  String request = String((char *)packetBuffer);

  if(request.indexOf('M-SEARCH') > 0) {
      if(request.indexOf("urn:Belkin:device:**") > 0) {
        Serial.println("Got UDP Belkin Request..");
        
        // int arrSize = sizeof(switchs) / sizeof(Switch);
      
        for(int n = 0; n < numOfSwitchs; n++) {
            Switch &sw = switches[n];

            if (&sw != NULL) {
              sw.respondToSearch(senderIP, senderPort);              
            }
        }
      }
  }
}```

Answer 1

The Arduino UDP API as defined by the UDP base class in Arduino core has

uint8_t beginMulticast(IPAddress, uint16_t); 

In esp8266 Arduino WiFi the UDP is modified and the first parameter of beginMulticast specifies the network interface to listen to. (Network interfaces are STA, SoftAP, Ethernet etc)

In esp32 Arduino WiFi library beginMulticast has only the standard parameters and listens on all network interfaces.

Your solution is to remove the first parameter in the beginMulticast call.