Should true or false terminate callback iteration?

Question

In some languages it's necessary or cleaner to do iteration by providing a callback function that receives items and returns a boolean that indicates whether to continue or stop the iteration.

Which is the preferred value to indicate desire to stop/continue? Why? What precedents exist?

Example in Go:

func IntSliceEach(sl []int, cb func(i int) (more bool)) (all bool) {
    for _, i := range sl {
        if !cb(i) {
            return false
        }
    }
    return true
}

Answer 1

Which is the preferred value to indicate desire to stop/continue?

true for continue

Why?

Example 1:

func example(i interface{}) {
    if w, ok := i.(io.Writer); ok {
        // do something with your writer, ok indicates that you can continue
    }
}

Example 2:

var sum int = 0
it := NewIntStatefulIterator(int_data)
for it.Next() {
    sum += it.Value()
}

In both cases true (ok) indicates that you should continue. So I assume that it would be way to go in your example.