Checks if all of the characters in the provided string,
text, are control characters.
Control characters are e.g. line feed, tab, esc.
参数
text
The tested string.
返回值
Returns TRUE if every character in text is
a letter from the current locale, FALSE otherwise.
范例
例子 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"; } } ?>
上例将输出：
The string 'string1' consists of all control characters.
The string 'string2' does not consists of all control characters.
