[RESOLU]Erreur de compilation pour la carte Arduino/Genuino Uno-MacOS

Bonjour,
J'ai un problème avec la compilation de mon Arduino. J'utilise Arduino 1.8.6.

Ce code fonctionne:
const int CONNEXION=13;
int tempsDePause;

void setup()
{
pinMode(CONNEXION,OUTPUT); //connexion 13
tempsDePause=100;
}

void loop()
{
digitalWrite(CONNEXION,LOW); //allume DEL 13
delay(tempsDePause); //Attends 1 seconde
digitalWrite(CONNEXION,HIGH); //éteint DEL 13
delay(tempsDePause); //Attends 1 seconde
tempsDePause=tempsDePause + 100;
}

Mais quand je tente avec ce code:

void setup()
{
Serial.begin(9600);
Serial.println("Communication OK");
}

void lopp()
{
Serial.println("Hello World");
}

J'obtiens ce message d'erreur:
/Users/florian/Desktop/Arduino.app/Contents/Java/arduino-builder -dump-prefs -logger=machine -hardware /Users/florian/Desktop/Arduino.app/Contents/Java/hardware -tools /Users/florian/Desktop/Arduino.app/Contents/Java/tools-builder -tools /Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -built-in-libraries /Users/florian/Desktop/Arduino.app/Contents/Java/libraries -libraries /Users/florian/Documents/Arduino/libraries -fqbn=arduino:avr:uno -vid-pid=0X2341_0X0043 -ide-version=10806 -build-path /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552 -warnings=all -build-cache /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_cache_830227 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.avrdude.path=/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -prefs=runtime.tools.avr-gcc.path=/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -prefs=runtime.tools.arduinoOTA.path=/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -verbose /Users/florian/Desktop/serial_monitor/serial_monitor.ino
/Users/florian/Desktop/Arduino.app/Contents/Java/arduino-builder -compile -logger=machine -hardware /Users/florian/Desktop/Arduino.app/Contents/Java/hardware -tools /Users/florian/Desktop/Arduino.app/Contents/Java/tools-builder -tools /Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -built-in-libraries /Users/florian/Desktop/Arduino.app/Contents/Java/libraries -libraries /Users/florian/Documents/Arduino/libraries -fqbn=arduino:avr:uno -vid-pid=0X2341_0X0043 -ide-version=10806 -build-path /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552 -warnings=all -build-cache /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_cache_830227 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.avrdude.path=/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -prefs=runtime.tools.avr-gcc.path=/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -prefs=runtime.tools.arduinoOTA.path=/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr -verbose /Users/florian/Desktop/serial_monitor/serial_monitor.ino
Using board 'uno' from platform in folder: /Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr
Using core 'arduino' from platform in folder: /Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr
Detecting libraries used...
/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr/bin/avr-g++ -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10806 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -I/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr/cores/arduino -I/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr/variants/standard /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/sketch/serial_monitor.ino.cpp -o /dev/null
Generating function prototypes...
/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr/bin/avr-g++ -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10806 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -I/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr/cores/arduino -I/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr/variants/standard /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/sketch/serial_monitor.ino.cpp -o /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/preproc/ctags_target_for_gcc_minus_e.cpp
/Users/florian/Desktop/Arduino.app/Contents/Java/tools-builder/ctags/5.8-arduino11/ctags -u --language-force=c++ -f - --c++-kinds=svpf --fields=KSTtzns --line-directives /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/preproc/ctags_target_for_gcc_minus_e.cpp
Compilation du croquis...
/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr/bin/avr-g++ -c -g -Os -Wall -Wextra -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -MMD -flto -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10806 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -I/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr/cores/arduino -I/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr/variants/standard /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/sketch/serial_monitor.ino.cpp -o /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/sketch/serial_monitor.ino.cpp.o
Compiling libraries...
Compiling core...
Using precompiled core: /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_cache_830227/core/core_arduino_avr_uno_9e3af6d4d338b97eef4310b3814958d1.a
Linking everything together...
/Users/florian/Desktop/Arduino.app/Contents/Java/hardware/tools/avr/bin/avr-gcc -Wall -Wextra -Os -g -flto -fuse-linker-plugin -Wl,--gc-sections -mmcu=atmega328p -o /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/serial_monitor.ino.elf /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/sketch/serial_monitor.ino.cpp.o /var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552/../arduino_cache_830227/core/core_arduino_avr_uno_9e3af6d4d338b97eef4310b3814958d1.a -L/var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T/arduino_build_282552 -lm
/var/folders/l8/7mqydjyj6bl1z51bwc5qp36w0000gn/T//ccf3q8o2.ltrans0.ltrans.o: In function main': /Users/florian/Desktop/Arduino.app/Contents/Java/hardware/arduino/avr/cores/arduino/main.cpp:46: undefined reference to loop'
collect2: error: ld returned 1 exit status
exit status 1
Erreur de compilation pour la carte Arduino/Genuino Uno

Pouvez-vous m'aider?

J'ai déjà désinstallé et réinstallé l'IDE mais rien ne change.

Ooooooopps...

void [color=red]lopp[/color]()
{
  Serial.println("Hello World");
}

C'est si con!! Merci