The pack() function is an inbuilt function in PHP which is used to pack the given parameter into a binary string in a given format.
Syntax:
pack( $format, $arguments )
Parameters: This function accepts two parameters as mentioned above and described below:
- $format: It is required parameter. It specifies the format to be used while packing the data. The possible values of format are:
- a - string which is NUL-padded
- A - string which is SPACE-padded
- h - low nibble first Hex string
- H - high nibble first Hex string
- c - signed character
- C - unsigned character
- s - signed short (16 bit, machine byte order)
- S - unsigned short ( 16 bit, machine byte order)
- n - unsigned short ( 16 bit, big endian byte order)
- v - unsigned short ( 16 bit, little endian byte order)
- i - signed integer (machine dependent byte order and size)
- I - unsigned integer (machine dependent byte order and size)
- l - signed long ( 32 bit, machine byte order)
- L - unsigned long ( 32 bit, machine byte order)
- N - unsigned long ( 32 bit, big endian byte order)
- V - unsigned long ( 32 bit, little endian byte order)
- f - float (machine dependent representation and size)
- d - double (machine dependent representation and size)
- x - NUL byte
- X - Back up one byte
- Z - string which is NUL-padded
- @ - NUL-fill to absolute position
- $arguments: It is Optional parameter. It specifies one or more arguments to be packed.
Return Value: It returns a binary string containing data.
Note: This function is available on PHP 4.0.0 and newer version.
Program 1: This program uses
C format to format the input parameter.
php
<?php
echo pack("C13", 71, 69, 69, 75, 83, 70, 79, 82, 71, 69, 69, 75, 83);
?>
This program uses
A format to format the input parameter.
php
<?php
echo pack("A3", 71898);
?>
This program uses
i format to format the input parameter.
php
<?php
echo pack("i3", 56, 49, 54);
?>
Explore
Basics
Array
OOPs & Interfaces
MySQL Database
PHP Advance