In PHP, what is binary string?

Question

like this: $str=b'xxxxxx';

Answer 1

$number = decbin(59);
echo $number . "\n"; //111011
$number = bindec($number);
echo $number . "\n"; //59

decbin(int $number): Returns a string containing a binary representation of the given number argument.

bindec(string $bstring): Returns the decimal equivalent of the binary number in bstring argument.

Answer 2

The PHP language reference describes the distinction between unicode strings and native binary strings, denoted with b'this is a binary string'

It doesn't seem to be a method of representing binary numbers.

The notation "is available since PHP 5.2.1. However, it will only have effect as of PHP 6.0.0"

Answer 3

"binary string" is what we have in php right now - a sequence of bytes, which (as opposed to C language) can also include nul byte. This is (or will be, as of php6) different from unicode strings, which are sequences of two-byte characters.