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

ctype_cntrlCheck for control character(s)


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.



The tested string.


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.

Return Values

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


Example #1 A ctype_cntrl() example

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

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User Contributed Notes 1 note

8 years ago
Returns true if bytes are in the range of \x00-\x1f or \x7f (del). Returns false if bytes are in the range of \x20-\x7e or \x80-\xff.
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