(PHP 4 >= 4.0.6, PHP 5, PHP 7) Set/Get substitution character

(PHP 4 >= 4.3.0, PHP 5, PHP 7) Make a string uppercase

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Returns start point for next regular expression match

(PHP 5 >= 5.2.0, PHP 7) Finds the last occurrence of a character in a string within another, case insensitive

(PHP 5 >= 5.2.0, PHP 7) Finds position of last occurrence of a string within another, case insensitive

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Get MIME charset string

(PHP 4 >= 4.3.0, PHP 5, PHP 7) Set/Get the default options for mbregex functions

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Retrieve the result from the last multibyte regular expression match

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Set/Get character encoding for multibyte regex

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Set/Get HTTP output character encoding