0x0001

0x0001 is a hexadecimal numeral commonly used in computing to denote the decimal value 1. The 0x prefix signals hexadecimal notation, and the digits 0001 together represent the value one. In binary, 0x0001 corresponds to a single set bit: for a 16-bit representation it is 0000 0000 0000 0001, and for a 32-bit representation it is 0000 0000 0000 0000 0000 0000 0000 0001.

Endianness matters when 0x0001 is stored or transmitted as a multi-byte quantity. In little-endian memory, a 32-bit value of 0x00000001 is stored as 01 00 00 00; in big-endian, it is stored as 00 00 00 01. The numerical value remains 1, but the byte order can affect parsing in low-level I/O, file formats, and network protocols.

Common usage focuses on bit-level operations. 0x0001 often serves as a bitmask for the least-significant bit, used to test, set, or clear that bit in a composite flag. For example, combining flags might involve bitwise OR with 0x0001, while checking a flag could use bitwise AND with 0x0001. Padding with leading zeros is a stylistic choice and does not change the value; 0x1 and 0x0001 are equivalent.

Context is key: a specific meaning for 0x0001 depends on the protocol, file format, or software system in which it appears. As a general-purpose literal, it is a basic building block for binary data representation and flag handling.

See also: hexadecimal notation, bitmask, endianness.