php man page for ctype_cntrl

CTYPE_CNTRL(3)								 1							    CTYPE_CNTRL(3)

ctype_cntrl - Check for control character(s)

SYNOPSIS
       bool ctype_cntrl (string  $text)

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

PARAMETERS
	      o $text
		- The tested string.

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

EXAMPLES
       Example #1

	      A ctype_cntrl(3) example

	      <?php
	      $strings = array('string1' => "

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

	      The above example will output:

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

NOTES
       Note

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

SEE ALSO
       ctype_print(3).

PHP Documentation Group 													    CTYPE_CNTRL(3)