diff --git a/cores/esp8266/Arduino.h b/cores/esp8266/Arduino.h
index fa65a2d02..8f440f27b 100644
--- a/cores/esp8266/Arduino.h
+++ b/cores/esp8266/Arduino.h
@@ -191,12 +191,12 @@ void initVariant(void);
 
 int atexit(void (*func)()) __attribute__((weak));
 
-void pinMode(uint8_t, uint8_t);
-void digitalWrite(uint8_t, uint8_t);
-int digitalRead(uint8_t);
-int analogRead(uint8_t);
+void pinMode(uint8_t pin, uint8_t mode);
+void digitalWrite(uint8_t pin, uint8_t val);
+int digitalRead(uint8_t pin);
+int analogRead(uint8_t pin);
 void analogReference(uint8_t mode);
-void analogWrite(uint8_t, int);
+void analogWrite(uint8_t pin, int val);
 void analogWriteFreq(uint32_t freq);
 void analogWriteRange(uint32_t range);
 
@@ -210,8 +210,8 @@ unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout);
 void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val);
 uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder);
 
-void attachInterrupt(uint8_t, void (*)(void), int mode);
-void detachInterrupt(uint8_t);
+void attachInterrupt(uint8_t pin, void (*)(void), int mode);
+void detachInterrupt(uint8_t pin);
 
 void setup(void);
 void loop(void);