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 = logical-or-expr | assignment-expr except that logical-or-expr is evaluated only once.

The keyword or_eq is interchangeable with the |= token.

Example

unsigned bitmask = 0xF0F0;
bitmask |= 0x0102; // bitmask becomes 0xF1F2.

See Also

and_eq, bitor, expression, xor_eq, Chapter 3, <ciso646>