unpack()

unpack() — Unpack data from binary string.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

Unpacks from a binary string into an array according to the given format.

Signature

unpack(string $format, string $string, int $offset = 0): array|false

Parameters

Parameter	Type	What it takes
$format	string	See pack() for an explanation of the format codes.
$string	string	The packed data.
$offset	int	The offset to begin unpacking from.

Return value

Returns an associative array containing unpacked elements of binary string, or false on failure.

Example

A runnable snippet:

$binarydata = "\x04\x00\xa0\x00"; $array = unpack("cchars/nint", $binarydata); print_r($array);

Output:

Array ( [chars] => 4 [int] => 160 )

Changelog

Version	Change
7.2.0	float and double types supports both Big Endian and Little Endian.
7.1.0	The optional offset has been added.