ctype_cntrl

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

Check for control character(s)

bool ctype_cntrl ( string $text )

Checks if all of the characters in the provided string, text, are control characters. Control characters are e.g. line feed, tab, escape.

Parameters:

text

The tested string.

Returns:

Returns TRUE if every character in text is a control character from the current locale, FALSE otherwise.

Notes:

If an integer between -128 and 255 inclusive is provided, it is interpreted as the ASCII value of a single character (negative values have 256 added in order to allow characters in the Extended ASCII range). Any other integer is interpreted as a string containing the decimal digits of the integer.

Examples:

A ctype_cntrl() example

<?php
$strings = array('string1' => "\n\r\t", 'string2' => 'arf12');
foreach ($strings as $name => $testcase) {
    if (ctype_cntrl($testcase)) {
        echo "The string '$name' consists of all control characters.\n";
    } else {
        echo "The string '$name' does not consist of all control characters.\n";
    }
}
?>

The above example will output:

The string 'string1' consists of all control characters.
The string 'string2' does not consist of all control characters.