Cannot declare variable 'server' to be of abstract type 'EthernetServer' | Together C & C++ | Page 1

jolly karma Mar 27, 2024, 11:51 AM

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Hello guys
I have a big problem with my Ethernet Webserver. Wifi runs perfect, but Ethernet wont work at all.
I have the W5500 Chip and no matter what i do, i always get this Error:

Compilation error: cannot declare variable 'server' to be of abstract type 'EthernetServer'

The Server ist for a project at work and is very important.
Anyone have a fix for it maybe? 🙂
Thanks and Greetings

balmy dewBOT Mar 27, 2024, 11:51 AM

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Remember to ask specific questions, provide necessary details, and reduce your question to its simplest form. For tips on how to ask a good question use !howto ask.

jolly karma Mar 27, 2024, 11:51 AM

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#include <SPI.h>
#include <Ethernet.h>

class MyServer : public EthernetServer {
public:
MyServer(uint16_t port) : EthernetServer(port) {
}
};

// MAC address for your Ethernet shield
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
// IP address for your ESP32
IPAddress ip(192, 168, 8, 120);
// Subnet mask for your network
IPAddress subnet(255, 255, 255, 0);
// Gateway IP for your network
IPAddress gateway(192, 168, 8, 1);

// Ethernet Server on port 80 (http port)

void setup() {
// Initializing serial port for debugging purposes
Serial.begin(9600);
EthernetServer server(80);
while (!Serial) {
; // Wait for serial port to connect
}

// Initializing ethernet device
Ethernet.init(15); // Use Ethernet.init(pin) to configure the CS pin
Ethernet.begin(mac, ip, gateway, subnet);

// Check for Ethernet hardware present
if (Ethernet.hardwareStatus() == EthernetNoHardware) {
Serial.println("Ethernet shield was not found. Sorry, can't run without hardware. :(");
while (true) {
delay(1); // Do nothing, no point running without Ethernet hardware
}
}
if (Ethernet.linkStatus() == LinkOFF) {
Serial.println("Ethernet cable is not connected.");
}

// Start server
server.begin();
Serial.print("Server is at ");
Serial.println(Ethernet.localIP());
}

void loop() {
// Listen for incoming clients
EthernetClient client = server.available();
if (client) {
Serial.println("New client");

waxen crest Mar 27, 2024, 11:52 AM

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thanks for opening the thread 👍

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so, as I said

jolly karma Mar 27, 2024, 11:52 AM

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Thank you! 🙂

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You maybe have a fix for it? Im really desperate 😄

waxen crest Mar 27, 2024, 11:53 AM

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EthernetServer must have member functions that don't have an implementation. You have to look for member functions marked virtual ... = 0; in the EthernetServer class, including in EthernetServer's base classes. Then you need to make sure all such functions are overridden and have an implementation in EthernetServer (or in one of its base classes). If they don't, EthernetServer is an abstract type and cannot be instantiated, hence the error.

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if you're using a network library, this should all be stated in the documentation and you should refer to that primarily

jolly karma Mar 27, 2024, 11:54 AM

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So if i understand it right, i have to go to my library, for example Ethernet2 and look for the Ethernetserver (C++ File) and in that file looke for "virtual ... = 0"?

waxen crest Mar 27, 2024, 11:55 AM

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if you are indeed using a library then the first thing you should do is reading the documentation

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this has to be explained somewhere, possibly with examples if you're lucky

jolly karma Mar 27, 2024, 11:55 AM

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The problem is, i run the Example from the library im using, and even in the example i get the same error code

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So the example simply doesnt work

waxen crest Mar 27, 2024, 11:56 AM

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well then maybe the library is fucked up yamikek

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that would be unfortunate

jolly karma Mar 27, 2024, 11:57 AM

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I tried Ethernet.h, Ethernet2.h and Ethernet3.h, in every library i get the same error code even with the examples

waxen crest Mar 27, 2024, 11:57 AM

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what library is it

jolly karma Mar 27, 2024, 11:58 AM

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Ethernet library

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Ethernet2 library

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Ethernet3 library

waxen crest Mar 27, 2024, 11:58 AM

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are those the name of it

jolly karma Mar 27, 2024, 11:58 AM

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yes i guess so

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well yeah

waxen crest Mar 27, 2024, 11:59 AM

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can you post a link to them, I can't find them

jolly karma Mar 27, 2024, 11:59 AM

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one moment

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https://github.com/adafruit/Ethernet2

GitHub

GitHub - adafruit/Ethernet2: WIZ5500 based Ethernet Shield library

WIZ5500 based Ethernet Shield library. Contribute to adafruit/Ethernet2 development by creating an account on GitHub.

waxen crest Mar 27, 2024, 12:00 PM

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first issue right there

jolly karma Mar 27, 2024, 12:00 PM

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thats the one i tried next

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The "Ethernet" library

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But its the same issue

waxen crest Mar 27, 2024, 12:03 PM

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and are you certain that the EthernetServer server; variable that you're declaring is actually of the type EthernetServer from the official Arduino Ethernet library?

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sounds to me like a potential issue

jolly karma Mar 27, 2024, 12:04 PM

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I dont really know what you mean 😦 I hope you can still help me.
I just installed the official Arduino Ethernet library and try to run this example.
Then this Error occured which i cant get rid of and dont find anything on the internet about this problem

waxen crest Mar 27, 2024, 12:05 PM

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I don't know how arduino things work unfortunately, but what's your compiler and how do you configure it?

jolly karma Mar 27, 2024, 12:06 PM

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I compile it with Arduino IDE

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Thats the library

waxen crest Mar 27, 2024, 12:06 PM

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and does the Arduino IDE allow you to configure include paths?

jolly karma Mar 27, 2024, 12:06 PM

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What do you mean exactly? :/

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oh

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i think i know what u mean

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i can open them and modify them. if i understand you correctly

waxen crest Mar 27, 2024, 12:07 PM

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include paths are IDE/compiler settings which basically tell where to look for files that you #include in your own source code

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my guess is that you have an #include "ethernet_server.h" or something that points to the deprecated library rather than to the official one

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if that turns out to be the case, you need to fix it by correcting your include paths

jolly karma Mar 27, 2024, 12:09 PM

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this is the ethernet.h

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in there i searched for "virtual"

waxen crest Mar 27, 2024, 12:11 PM

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yeah I could have a look at that header on the repo, I didn't find any pure virtual functions

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(those are all virtual, not pure virtual)

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can you have a look at your include paths?

jolly karma Mar 27, 2024, 12:12 PM

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i need to look how to do it

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or what you mean exactly?
#include SPI.h
and
#include Ethernet.h

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?

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Ah

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i found it i guess

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i can go to the path yeah

waxen crest Mar 27, 2024, 12:13 PM

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I just looked it up, you can't configure include paths in Arduino IDE, it just looks for headers in a standard location

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can you show the contents of your whole "Libraries" directory please?

jolly karma Mar 27, 2024, 12:14 PM

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yes!

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📎 Ethernet.h

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that is the Ethernet.h

waxen crest Mar 27, 2024, 12:16 PM

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So in there, Ethernet is the official Arduino ethernet library, and Ethernet2 and 3 are some kind of spin-offs?

jolly karma Mar 27, 2024, 12:16 PM

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Yes right

waxen crest Mar 27, 2024, 12:16 PM

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alright

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can you remove them entirely? yamikek

jolly karma Mar 27, 2024, 12:16 PM

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haha

waxen crest Mar 27, 2024, 12:16 PM

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from this directory at least

jolly karma Mar 27, 2024, 12:16 PM

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i can yeah

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i move them in a backup folder on my desktop

waxen crest Mar 27, 2024, 12:17 PM

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sure

jolly karma Mar 27, 2024, 12:17 PM

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so just include the Ethernet libary?

waxen crest Mar 27, 2024, 12:17 PM

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yes

jolly karma Mar 27, 2024, 12:17 PM

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or also remove it?

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ok

waxen crest Mar 27, 2024, 12:17 PM

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you keep the official Ethernet library

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now if you recompile does that make it any better

jolly karma Mar 27, 2024, 12:18 PM

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i just removed the librarys, i now check again

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kekw

waxen crest Mar 27, 2024, 12:19 PM

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same error then

jolly karma Mar 27, 2024, 12:20 PM

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yeah 😦

waxen crest Mar 27, 2024, 12:20 PM

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is that the top most error?

jolly karma Mar 27, 2024, 12:20 PM

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yes

waxen crest Mar 27, 2024, 12:20 PM

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like you can't scroll up above the error complaining about server being of abstract type

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the path of your file looks... weird

jolly karma Mar 27, 2024, 12:21 PM

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this is the whole log

waxen crest Mar 27, 2024, 12:22 PM

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okay so at least it is including the correct ethernet header

jolly karma Mar 27, 2024, 12:22 PM

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yes i checked that already

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or i think i did 😄

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the file that i sent you, that is the header, right?

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Ethernet.h?

waxen crest Mar 27, 2024, 12:22 PM

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yes

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what concerns me now is that it tries to explain why it is abstract, namely because there are pure virtual functions and then it... shows the class declaration?

jolly karma Mar 27, 2024, 12:23 PM

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so this is the class you were talking about, right?

waxen crest Mar 27, 2024, 12:25 PM

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oh don't mind it I read that sideways

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is says that this function

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is not implemented in EthernetServer

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(it's part of EthernetServer's base class Server)

jolly karma Mar 27, 2024, 12:26 PM

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ok but this is in the appdata folder right? so its a "tempory" folder? am i right?

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or do i completly missunderstand this?

waxen crest Mar 27, 2024, 12:27 PM

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it's not temporary

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that seems to be where the arduino core libraries are located

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so anyway yes in order not to be abstract anymore EthernetServer needs to override void begin(uint16_t port)

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but EthernetServer only seems to override void begin()

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that's what causing the issue

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so all in all this looks like a version mismatch

jolly karma Mar 27, 2024, 12:30 PM

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Oh ok

waxen crest Mar 27, 2024, 12:30 PM

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because the Ethernet library seems to be expecting support that is not offered by your core libraries

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maybe update both, I don't know how that goes

jolly karma Mar 27, 2024, 12:30 PM

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Can i fix that myself by editing the files somehow? Hope you know what i mean with that

waxen crest Mar 27, 2024, 12:31 PM

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this page mentions a Library Manager https://www.arduino.cc/reference/en/libraries/ethernet/

Ethernet - Arduino Reference

The Arduino programming language Reference, organized into Functions, Variable and Constant, and Structure keywords.

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maybe you can use it to get up to date libs

waxen crest Mar 27, 2024, 12:31 PM

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jolly karma Can i fix that myself by editing the files somehow? Hope you know what i mean wi...

you probably can but I have no idea how and figuring that out is not a rabbit hole I'm willing to go into 😛

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updating your libs to matching versions is way easier anyway

jolly karma Mar 27, 2024, 12:34 PM

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Ok i will try it!! Thank you a lot already!!

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Im Kinda Desperate because im trying to get the Webserver working for a project at Work and i thought it would be way easier than it actually is.
Wifi Webserver works 100% but IT at our Company dont Like wifi 😂

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kekw

waxen crest Mar 27, 2024, 12:36 PM

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good luck then 👍

jolly karma Mar 27, 2024, 12:38 PM

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Thank you! 🙂

balmy dewBOT Mar 27, 2024, 12:43 PM

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@jolly karma Has your question been resolved? If so, type !solved :)

jolly karma Mar 27, 2024, 12:50 PM

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Compilation error: no matching function for call to 'EthernetServer::begin()'

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I get this Error now, the other one is gone 🙂

waxen crest Mar 27, 2024, 1:18 PM

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well now you've got matching libs at least

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can you post the line that provokes this error?

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must only be a matter of providing an argument

jolly karma Mar 27, 2024, 1:21 PM

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C:\Users\Brunndan\AppData\Local\Temp.arduinoIDE-unsaved2024227-18340-1ll8nsc.5m5l\sketch_mar27b\sketch_mar27b.ino: In function 'void setup()':
C:\Users\Brunndan\AppData\Local\Temp.arduinoIDE-unsaved2024227-18340-1ll8nsc.5m5l\sketch_mar27b\sketch_mar27b.ino:31:16: error: no matching function for call to 'EthernetServer::begin()'
server.begin();
^
In file included from C:\Users\Brunndan\AppData\Local\Temp.arduinoIDE-unsaved2024227-18340-1ll8nsc.5m5l\sketch_mar27b\sketch_mar27b.ino:2:
c:\Users\Brunndan\Documents\Arduino\libraries\Ethernet\src/Ethernet.h:261:15: note: candidate: 'virtual void EthernetServer::begin(uint16_t)'
virtual void begin(uint16_t port);
^~~~~
c:\Users\Brunndan\Documents\Arduino\libraries\Ethernet\src/Ethernet.h:261:15: note: candidate expects 1 argument, 0 provided

exit status 1

Compilation error: no matching function for call to 'EthernetServer::begin()'

you mean this?

waxen crest Mar 27, 2024, 1:26 PM

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yeah

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just call it like server.begin(0); or whatever you want the port number to be

jolly karma Mar 27, 2024, 1:28 PM

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Now im stuck on even more errors 😛

waxen crest Mar 27, 2024, 2:09 PM

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somehow it's your Ethernet header which still seems to be wrong

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well not the header, the source file that comes with it

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it's the call to .begin() in EthernetServer.cpp line 71 which is incorrect

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I guess just stick a 0 in there too at this point idk lol

#Cannot declare variable 'server' to be of abstract type 'EthernetServer'