Core PHP Programming: Using PHP to Build Dynamic Web Sites

Bitwise Operators

A binary digit, which may be 1 or 0, is called a bit. Bitwise operators are similar to logical operators, but where logical operators work on TRUE and FALSE, bitwise operators view numbers from a binary perspective. When using logical operators, 1 and 10 are both TRUE, but to a bitwise operator 1 looks like 0001 and 10 looks like 1010. A logical AND of 1 and 10 results in TRUE. A bitwise AND of 1 and 10 results in 0. This is because each bit of the two numbers is compared by a bitwise AND. Table 2.7 lists PHP's bitwise operators.

See Table 2.8 for an example of a bitwise operation, which shows that (12 & 10) == 8. Matching bits are operated on. In the rightmost position 0 and 0 are operated on with a bitwise AND. The result ...