operator xor (operand1, operand2: Boolean) = Result: Boolean;
or
operator xor (operand1, operand2: integer_type) = Result: integer_type;
or
procedure xor (var operand1: integer_type; operand2: integer_type);
In GNU Pascal, xor has three built-in meanings:
ISO Pascal does not define the xor operator; Borland Pascal and Delphi do.
Use of xor as a “procedure” is a GNU Pascal extension.
program XorDemo; var a, b, c: Integer; begin if (a = 0) xor (b = 0) then c := 1 { happens if either `a' or `b' is zero, } { but not if both are zero or both nonzero } else if (a xor b) = 0 then { bitwise xor } c := 2 { happens if a = b } else xor (c, a) { same as `c := c xor a' } end.