Function declared as unsigned long - no compile

Forum 2005-2010 (read only) Software Syntax & Programs
1

I need some help understanding something. First, the code:

int encoder = 4;
unsigned long speed = 0;

void setup() 
{ 
  pinMode(encoder, INPUT);
}
 
void loop() 
{ 
    speed = getspeed();
    delay(1000);  
} 

//unsigned long getspeed()   // THIS IS WHAT I THOUGHT WOULD WORK
long getspeed()                   // THIS IS WHAT WORKS
{
  unsigned long duration = 0;
  duration = pulseIn(encoder, HIGH);
  return(duration);
}

I would like to return an unsigned long from function getspeed(), but unless I declare it long it won't compile. I get this error:

In function 'void loop()':
error: 'getspeed' was not declared in this scope

What am I missing here? (In my dreadful ignorance of coding, I should add)

2

I should add (having just discovered) that the comments in caps must be removed. I added them in the forum post editor - so when I double checked my posted code NOTHING compiled!

3

The problem is not with your code, it's the automatic prototyping the arduino environment does seems to be the issue.

If you add an explicit prototype to the top your sketch will compile

unsigned long getspeed(); // prototype added here

int encoder = 4;
unsigned long speed = 0;

void setup() 
{ 
  pinMode(encoder, INPUT);
}

void loop() 
{ 
    speed = getspeed();
    delay(1000);  
} 

unsigned long getspeed()
{
  unsigned long duration = 0;
  duration = pulseIn(encoder, HIGH);
  return(duration);
}
4

That makes sense.
Now that my bot is "hardware complete", it's time to concentrate on code. I brought my K&R to work for lunchtime reading. Those programming classes I took seem long ago and far away!