php man page for hex2bin

HEX2BIN(3)								 1								HEX2BIN(3)

hex2bin - Decodes a hexadecimally encoded binary string

SYNOPSIS
       string hex2bin (string  $data)

DESCRIPTION
	Decodes a hexadecimally encoded binary string.

       Caution

	       This function does NOT convert a hexadecimal number to a binary number. This can be done using the base_convert(3) function.

PARAMETERS
	      o $data
		- Hexadecimal representation of data.

RETURN VALUES
	Returns the binary representation of the given data or FALSE on failure.

ERRORS
/EXCEPTIONS
	If the hexadecimal input string is of odd length or invalid hexadecimal string an E_WARNING level error is thrown.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.5.1	|						    |
       |	|						    |
       |	|  A  warning  is  thrown  if  the  input string is |
       |	| invalid hexadecimal string.			    |
       |	|						    |
       | 5.4.1	|						    |
       |	|						    |
       |	|  A warning is thrown if the input  string  is  of |
       |	| odd  length. In PHP 5.4.0 the string was silently |
       |	| accepted, but the last byte was truncated.	    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      hex2bin(3) example

	      <?php
	      $hex = hex2bin("6578616d706c65206865782064617461");
	      var_dump($hex);
	      ?>

	      The above example will output something similar to:

	      string(16) "example hex data"

SEE ALSO
       bin2hex(3), unpack(3).

PHP Documentation Group 														HEX2BIN(3)