bitmask

Definitions

1. A pattern of bits used with bitwise operations (AND, OR, XOR) to manipulate or test specific bits within a value. Bitmasks are used for permission systems (Unix file permissions), feature flags, hardware register programming, and compact boolean storage. Each bit position represents an independent flag, allowing a single integer to encode multiple on/off states.

   In plain English: A technique that uses individual bits as on/off switches, letting you pack many yes/no values into a single number — how Unix file permissions work.

   Example: The Unix permission 755 is actually a bitmask: the owner gets read, write, and execute (111 = 7), while group and others get read and execute (101 = 5).

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