0x0004

0x0004 is a hexadecimal literal used in computing to denote the decimal value four. The prefix 0x indicates hexadecimal notation, and the trailing zeros are often a matter of width or alignment in data representations, but the underlying value remains four.

In binary and memory, 0x0004 corresponds to the bit pattern 0000 0000 0000 0100 for a 16-bit example. In little-endian storage, the bytes would appear as 04 00, whereas in big-endian storage they would appear as 00 04. This makes 0x0004 a simple, commonly used example for illustrating endianness and byte ordering in hex dumps and memory layouts.

As a bitmask, 0x0004 represents the third least significant bit (bit 2, counting from zero). It can be used in flag fields to indicate a specific option or feature when combined with other flags via bitwise operations (for example, testing or setting a flag with a value like 0x0004).

In character encoding terms, 0x04 is the ASCII/Unicode control code End of Transmission (EOT). In Unicode, this corresponds to code point U+0004, and in practice EOT has been used in serial and network protocols to signal the end of a data transmission.

Applications vary by system and protocol, but 0x0004 commonly appears as a small integer value, a bitmask, or a control code in data formats, programming languages, and communication standards. Its interpretation depends on the surrounding context, such as whether it is treated as an unsigned value, a flag, or a control character.

See also: hexadecimal notation, bitmask, endianness, End of Transmission (EOT), ASCII and Unicode control characters.