PHP Functions Essential Reference

pack

mixed pack(string format, mixed args, [mixed args]) 

format	Format to use to pack the data
args	Piece of data to be packed into the string
args	Zero or more additional arguments to be packed into the string

Creates a binary string from a list of values.

Returns:

Binary string; FALSE on error

Description:

pack() transforms a list of values into a sequence of bits based on a user-defined format. It’s a powerful tool that allows developers to work directly with binary data. pack() can be used for many purposes—from simple tasks such as trimming and padding strings to more complex tasks such as altering binary files.

Calls to the function look like this:

$binary_string = pack ('C4', 128, 9, 176, 32); 

The first argument contains the format ...