Wacky unknown pointer issues.

Projects Programming
17

BizarrePsycho:
And I believe the default for passing a struct into a function is pass by reference.

No, it isn't. Try this:

struct foo {
    int a;
    int b;
};

void bar (struct foo x)
  {
  x.a = 42;
  }
  
void setup () 
{
  struct foo y;
  y.a = 1;
  y.b = 2;

  Serial.begin (115200);
  Serial.println (y.a);
  bar (y);
  Serial.println (y.a);
  exit (0);  // little jest there
}
void loop () {}

That prints:

1
1

Now change bar to be:

void bar (struct foo & x)

That prints:

1
42

So the default, as with all other arguments, is call by value.