Only ascii 32 thru 126 (inclusive) are considered printable. Tab (ascii 7), carriage return (ascii 13), linefeed (ascii 10) etc may produce output but are not considered printable.
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
ctype_print — Verifica se os caracteres são imprimíveis
$text
) : bool
Verifica se todos os caracteres na string fornecida,
text
, são imprimíveis.
text
A string a ser testada.
Retorna true
se todos caracteres em text
irá produzir saída (incluindo em branco). Retorna false
se
text
contem caracteres de controle ou caracteres
que não tem uma saída ou funções de controle inteiramente.
Exemplo #1 Um exemplo da ctype_print()
<?php
$strings = array('string1' => "asdf\n\r\t", 'string2' => 'arf12', 'string3' => 'LKA#@%.54');
foreach ($strings as $name => $testcase) {
if (ctype_print($testcase)) {
echo "The string '$name' consists of all printable characters.\n";
} else {
echo "The string '$name' does not consist of all printable characters.\n";
}
}
?>
O exemplo acima irá imprimir:
The string 'string1' does not consist of all printable characters. The string 'string2' consists of all printable characters. The string 'string3' consists of all printable characters.
Only ascii 32 thru 126 (inclusive) are considered printable. Tab (ascii 7), carriage return (ascii 13), linefeed (ascii 10) etc may produce output but are not considered printable.
As mentioned above, only ASCII characters from 32 to 126 are considered printable, all others, including UTF-8 encoded characters are always considered unprintable, no matter what your locale settings are. Therefore, e.g. German "ä", the Euro sign "€" or the British pound symbol "£" will never be printable. If you need to check any characters for "printability" beyond the standard ASCII range, use a regular expression or write a specific function yourself.
See also this discussion: https://grokbase.com/t/php/php-i18n/102tkqe6rk/ctype-print-returns-false-for-british-pound-symbol-and-non-ascii-symbols