From QB64.org wiki
The = condition symbol denotes that a value must equal another value for the condition to be True.
Example usage: IF x = 320 THEN PRINT "Center of screen"
- Statements will evaluate as True or -1 when two values are equal or False or 0 when not equal.
- More than one = symbol in a numerical statement will create a Boolean evaluation of the ensuing numerical pairs.
- A = B = C will be converted to A = (B = C) so if B = C then A = -1. If not, then A = 0