||Bitwise or assignment operator
assignment-expr := logical-or-expr "|=" assignment-expr |
logical-or-expr or_eq assignment-expr
The or_eq operator is an assignment operator that
performs bitwise inclusive or. It is equivalent
to logical-or-expr =
assignment-expr except that
logical-or-expr is evaluated only once.
The keyword or_eq is interchangeable with the
unsigned bitmask = 0xF0F0;
bitmask |= 0x0102; // bitmask becomes 0xF1F2.
expression, xor_eq, Chapter 3, <ciso646>