0b11111111

0b11111111 is an eight-bit binary literal commonly used in programming to denote a byte whose bit pattern consists of eight 1s. The binary sequence 11111111 corresponds to the decimal value 255 in unsigned form, and to 0xFF in hexadecimal notation. The 0b prefix indicates a binary numeral in languages that support binary literals.

In an eight-bit unsigned interpretation, it is the maximum value representable by a byte. In many systems using two's complement for signed integers, the same bit pattern represents -1. The pattern is also used as a mask that selects all bits within a byte; for example, x & 0xFF extracts the least-significant byte of x. It is a common building block in byte-oriented operations and network protocols where data is divided into 8-bit chunks.

In practical usage, 0b11111111 appears in color processing as the maximum intensity for a color channel (red, green, or blue) in 8-bit-per-channel schemes, corresponding to 255. Some languages support binary literals with 0b prefixes (for example, Python and newer versions of JavaScript); others require hexadecimal or decimal representations. When writing portable code, care should be taken about whether a value is treated as signed or unsigned and about compiler support for binary literals.