GLib.CompareDataFunc

function onCompareDataFunc(a: void, b: void): Number(gint) {
}

Specifies the type of a comparison function used to compare two values. The function should return a negative integer if the first value comes before the second, 0 if they are equal, or a positive integer if the first value comes after the second.

a: a value
b: a value to compare with
Returns: negative value if a < b; zero if a = b; positive value if a > b