(PHP 6 >= 6.0.0)
is_buffer — Finds whether a variable is a native unicode or binary string
Finds whether the given variable is a native unicode or binary string.
The variable being evaluated.
Returns TRUE if var is a native unicode or binary string, FALSE otherwise.
Example #1 is_buffer() example
<?php
// Declare some variables with different types
$types = array(
            'unicode'    => 'Unicode string', 
            'binary'    => b'Binary string', 
            'resource'    => fopen('php://stdin', 'r'), 
            'integer'    => 42
            );
// Test which types thats a buffer
foreach($types as $type => $value)
{
    if(is_buffer($value))
    {
        echo $type . ' is a either a unicode or binary string';
    }
    else
    {
        echo $type . ' is not a buffer value';
    }
    echo PHP_EOL;
}
?>
위 예제의 출력:
unicode is a either a unicode or binary string binary is a either a unicode or binary string resource is not a buffer value integer is not a buffer value