Hello, somehow, the Example sketch "WebServer" doesn't want to compile 
Here's the code:
/*
Web Server
A simple web server that shows the value of the analog input pins.
using an Arduino Wiznet Ethernet shield.
Circuit:
* Ethernet shield attached to pins 10, 11, 12, 13
* Analog inputs attached to pins A0 through A5 (optional)
created 18 Dec 2009
by David A. Mellis
modified 9 Apr 2012
by Tom Igoe
modified 02 Sept 2015
by Arturo Guadalupi
*/
#include <SPI.h>
#include <Ethernet.h>
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
};
IPAddress ip(192, 168, 1, 177);
// Initialize the Ethernet server library
// with the IP address and port you want to use
// (port 80 is default for HTTP):
EthernetServer server(80);
void setup() {
// You can use Ethernet.init(pin) to configure the CS pin
//Ethernet.init(10); // Most Arduino shields
//Ethernet.init(5); // MKR ETH shield
//Ethernet.init(0); // Teensy 2.0
//Ethernet.init(20); // Teensy++ 2.0
//Ethernet.init(15); // ESP8266 with Adafruit Featherwing Ethernet
//Ethernet.init(33); // ESP32 with Adafruit Featherwing Ethernet
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
Serial.println("Ethernet WebServer Example");
// start the Ethernet connection and the server:
Ethernet.begin(mac, ip);
// 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 the 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");
// an http request ends with a blank line
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) {
char c = client.read();
Serial.write(c);
// if you've gotten to the end of the line (received a newline
// character) and the line is blank, the http request has ended,
// so you can send a reply
if (c == '\n' && currentLineIsBlank) {
// send a standard http response header
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("Connection: close"); // the connection will be closed after completion of the response
client.println("Refresh: 5"); // refresh the page automatically every 5 sec
client.println();
client.println("<!DOCTYPE HTML>");
client.println("<html>");
// output the value of each analog input pin
for (int analogChannel = 0; analogChannel < 6; analogChannel++) {
int sensorReading = analogRead(analogChannel);
client.print("analog input ");
client.print(analogChannel);
client.print(" is ");
client.print(sensorReading);
client.println("
");
}
client.println("</html>");
break;
}
if (c == '\n') {
// you're starting a new line
currentLineIsBlank = true;
} else if (c != '\r') {
// you've gotten a character on the current line
currentLineIsBlank = false;
}
}
}
// give the web browser time to receive the data
delay(1);
// close the connection:
client.stop();
Serial.println("client disconnected");
}
}
And here is the Error Msg:
Arduino: 1.8.7 (Linux), Board: "Arduino/Genuino Uno"
/tmp/ccTT56B7.ltrans1.ltrans.o: In function `IPAddress::printTo(Print&) const':
/home/username/arduino-1.8.7/hardware/arduino/avr/cores/arduino/IPAddress.cpp:108: undefined reference to `Print::print(unsigned char, int)'
/home/username/arduino-1.8.7/hardware/arduino/avr/cores/arduino/IPAddress.cpp:109: undefined reference to `Print::print(char)'
/home/username/arduino-1.8.7/hardware/arduino/avr/cores/arduino/IPAddress.cpp:111: undefined reference to `Print::print(unsigned char, int)'
/tmp/ccTT56B7.ltrans1.ltrans.o: In function `EthernetClass::socketBegin(unsigned char, unsigned int) [clone .part.1] [clone .lto_priv.65]':
/home/username/arduino-1.8.7/libraries/Ethernet/src/socket.cpp:106: undefined reference to `delayMicroseconds'
/tmp/ccTT56B7.ltrans1.ltrans.o: In function `EthernetClass::socketSend(unsigned char, unsigned char const*, unsigned int)':
/home/username/arduino-1.8.7/libraries/Ethernet/src/socket.cpp:444: undefined reference to `yield'
/home/username/arduino-1.8.7/libraries/Ethernet/src/socket.cpp:460: undefined reference to `yield'
/tmp/ccTT56B7.ltrans2.ltrans.o: In function `DNSClient::getHostByName(char const*, IPAddress&, unsigned int) [clone .constprop.26]':
/home/username/arduino-1.8.7/libraries/Ethernet/src/Dns.cpp:104: undefined reference to `millis'
/tmp/ccTT56B7.ltrans2.ltrans.o: In function `BuildRequest':
/home/username/arduino-1.8.7/libraries/Ethernet/src/Dns.cpp:157: undefined reference to `millis'
/tmp/ccTT56B7.ltrans2.ltrans.o: In function `ProcessResponse':
/home/username/arduino-1.8.7/libraries/Ethernet/src/Dns.cpp:216: undefined reference to `millis'
/home/username/arduino-1.8.7/libraries/Ethernet/src/Dns.cpp:220: undefined reference to `millis'
/home/username/arduino-1.8.7/libraries/Ethernet/src/Dns.cpp:223: undefined reference to `delay'
/tmp/ccTT56B7.ltrans2.ltrans.o:(.rodata+0x4): undefined reference to `__cxa_pure_virtual'
/tmp/ccTT56B7.ltrans2.ltrans.o:(.rodata+0x6): undefined reference to `Print::write(unsigned char const*, unsigned int)'
/tmp/ccTT56B7.ltrans2.ltrans.o:(.rodata+0xc): undefined reference to `__cxa_pure_virtual'
/tmp/ccTT56B7.ltrans2.ltrans.o:(.rodata+0xe): undefined reference to `__cxa_pure_virtual'
/tmp/ccTT56B7.ltrans2.ltrans.o:(.rodata+0x10): undefined reference to `__cxa_pure_virtual'
/tmp/ccTT56B7.ltrans2.ltrans.o:(.rodata+0x18): undefined reference to `Print::write(unsigned char const*, unsigned int)'
/tmp/ccTT56B7.ltrans2.ltrans.o:(.rodata+0x2e): undefined reference to `__cxa_pure_virtual'
/home/username/arduino-1.8.7/hardware/tools/avr/bin/../lib/gcc/avr/5.4.0/../../../../avr/lib/avr5/crtatmega328p.o:(.init9+0x0): undefined reference to `main'
/tmp/ccTT56B7.ltrans0.ltrans.o: In function `EthernetClient::stop()':
/home/username/arduino-1.8.7/libraries/Ethernet/src/EthernetClient.cpp:138: undefined reference to `millis'
/home/username/arduino-1.8.7/libraries/Ethernet/src/EthernetClient.cpp:146: undefined reference to `delay'
/home/username/arduino-1.8.7/libraries/Ethernet/src/EthernetClient.cpp:147: undefined reference to `millis'
/tmp/ccTT56B7.ltrans0.ltrans.o: In function `socketSendUDP':
/home/username/arduino-1.8.7/libraries/Ethernet/src/socket.cpp:527: undefined reference to `yield'
collect2: error: ld returned 1 exit status
exit status 1
Fehler beim Kompilieren für das Board Arduino/Genuino Uno.
Dieser Bericht wäre detaillierter, wenn die Option
"Ausführliche Ausgabe während der Kompilierung"
in Datei -> Voreinstellungen aktiviert wäre.
I hope someone could help me, because I'm a beginner and do not know what to do to make it work.
