(PHP 7, PHP 8)
IntlChar::charDigitValue — Get the decimal digit value of a decimal digit character
$codepoint): ?intReturns the decimal digit value of a decimal digit character.
Such characters have the general category "Nd" (decimal digit numbers) and a Numeric_Type of Decimal.
codepointLa valeur codepoint de type entier
(i.e. 0x2603 pour U+2603 SNOWMAN), ou le caractère encodé en UTF-8 de type chaîne de caractères
(i.e. "\u{2603}")
   The decimal digit value of codepoint,
   or -1 if it is not a decimal digit character. Returns null on failure.
  
Exemple #1 Test de différents codepoint
<?php
var_dump(IntlChar::charDigitValue("1"));
var_dump(IntlChar::charDigitValue("\u{0662}"));
var_dump(IntlChar::charDigitValue("\u{0E53}"));
?>
L'exemple ci-dessus va afficher :
int(1) int(2) int(3)