echo "<pre>";
print_r(get_extension_funcs("pcre"));
echo "</pre>";
/*
run:
Array
(
[0] => preg_match
[1] => preg_match_all
[2] => preg_replace
[3] => preg_replace_callback
[4] => preg_filter
[5] => preg_split
[6] => preg_quote
[7] => preg_grep
[8] => preg_last_error
)
*/