Differences from POSIX regex
preg_filter
PCRE
PHP Manual

# PCRE Functions

## Table of Contents

- preg_filter — Perform a regular expression search and replace
- preg_grep — Return array entries that match the pattern
- preg_last_error — Returns the error code of the last PCRE regex execution
- preg_match_all — Perform a global regular expression match
- preg_match — Perform a regular expression match
- preg_quote — Quote regular expression characters
- preg_replace_callback — Perform a regular expression search and replace using a callback
- preg_replace — Perform a regular expression search and replace
- preg_split — Split string by a regular expression

Differences from POSIX regex
preg_filter
PCRE
PHP Manual