Example compilation error - Arduino Ethernet Library (EthernetServer) on ESP32

[seansplayin]

C:\Users\seans\Documents\Arduino\libraries\SparkFun_WebServer_ESP32_W5500\examples\Example1_AsyncWebServer\Example1_AsyncWebServer.ino: In function 'void loop()':
C:\Users\seans\Documents\Arduino\libraries\SparkFun_WebServer_ESP32_W5500\examples\Example1_AsyncWebServer\Example1_AsyncWebServer.ino:210:43: error: invalid new-expression of abstract class type 'EthernetServer'
ethernetServer = new EthernetServer(80); //Instantiate the web server. Use port 80
^
In file included from C:\Users\seans\Documents\Arduino\libraries\SparkFun_WebServer_ESP32_W5500\examples\Example1_AsyncWebServer\Example1_AsyncWebServer.ino:52:
c:\Users\seans\Documents\Arduino\libraries\Ethernet\src/Ethernet.h:254:7: note: because the following virtual functions are pure within 'EthernetServer':
class EthernetServer : public Server {
^~~~~~~~~~~~~~
In file included from C:\Users\seans\AppData\Local\Arduino15\packages\esp32\hardware\esp32\2.0.14\cores\esp32/Arduino.h:182,
from C:\Users\seans\Documents\Arduino\libraries\SparkFun_WebServer_ESP32_W5500\examples\Example1_AsyncWebServer\Example1_AsyncWebServer.ino:16:
C:\Users\seans\AppData\Local\Arduino15\packages\esp32\hardware\esp32\2.0.14\cores\esp32/Server.h:28:18: note: 'virtual void Server::begin(uint16_t)'
virtual void begin(uint16_t port=0) =0;
^~~~~
Multiple libraries were found for "Ethernet.h"
Used: C:\Users\seans\Documents\Arduino\libraries\Ethernet
Not used: C:\Users\seans\AppData\Local\Arduino15\libraries\Ethernet
Not used: C:\Users\seans\Documents\Arduino\libraries\UIPEthernet
Not used: C:\Users\seans\Documents\Arduino\libraries\EthernetENC
exit status 1

Compilation error: invalid new-expression of abstract class type 'EthernetServer'

[PaulZC]

Hi @seansplayin ,

Thanks for reporting this.

The compilation error actually comes from the Arduino Ethernet Library and is discussed in this issue. The solution is to patch Server.h. Replace C:\Users\<Your User>\AppData\Local\Arduino15\packages\esp32\hardware\esp32\2.0.14\cores\esp32\Server.h with the modified copy here and all will be well.

I will pin this issue to make it easier to find.

Best wishes,
Paul