Check for control character(s)

# ctype_cntrl

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

ctype_cntrl — Check for control character(s)

### Description

ctype_cntrl(mixed `$text`): bool

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.

  > Note:

  > If an int 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.

  Warning

  As of PHP 8.1.0, passing a non-string argument is deprecated. In the future, the argument will be interpreted as a string instead of an ASCII codepoint. Depending on the intended behavior, the argument should either be cast to string or an explicit call to chr() should be made.

### Return Values

Returns `true` if every character in `text` is a control character from the current locale, `false` otherwise. When called with an empty string the result will always be `false`.

### Examples

Example #1 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.

### See Also

- ctype_print() - Check for printable character(s)
- IntlChar::iscntrl() - Check if code point is a control character

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