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The functions provided by this extension check whether a character or string falls into a certain character class according to the current locale.
When called with an integer argument these functions behave exactly like their C counterparts from ctype.h
Beginning with PHP 4.2.0 these functions are enabled by default. For older versions you have to configure and compile PHP with --enable-ctype. You can disable ctype support with --disable-ctype.
Builtin support for ctype is available with PHP 4.3.0.
This extension has no configuration directives defined in php.ini.
PHP: indicates the earliest version of PHP that supports the function.