echo "<pre>";
print_r(get_extension_funcs("mbstring"));
echo "</pre>";
/*
run:
Array
(
[0] => mb_convert_case
[1] => mb_strtoupper
[2] => mb_strtolower
[3] => mb_language
[4] => mb_internal_encoding
[5] => mb_http_input
[6] => mb_http_output
[7] => mb_detect_order
[8] => mb_substitute_character
[9] => mb_parse_str
[10] => mb_output_handler
[11] => mb_preferred_mime_name
[12] => mb_strlen
[13] => mb_strpos
[14] => mb_strrpos
[15] => mb_stripos
[16] => mb_strripos
[17] => mb_strstr
[18] => mb_strrchr
[19] => mb_stristr
[20] => mb_strrichr
[21] => mb_substr_count
[22] => mb_substr
[23] => mb_strcut
[24] => mb_strwidth
[25] => mb_strimwidth
[26] => mb_convert_encoding
[27] => mb_detect_encoding
[28] => mb_list_encodings
[29] => mb_encoding_aliases
[30] => mb_convert_kana
[31] => mb_encode_mimeheader
[32] => mb_decode_mimeheader
[33] => mb_convert_variables
[34] => mb_encode_numericentity
[35] => mb_decode_numericentity
[36] => mb_send_mail
[37] => mb_get_info
[38] => mb_check_encoding
[39] => mb_regex_encoding
[40] => mb_regex_set_options
[41] => mb_ereg
[42] => mb_eregi
[43] => mb_ereg_replace
[44] => mb_eregi_replace
[45] => mb_ereg_replace_callback
[46] => mb_split
[47] => mb_ereg_match
[48] => mb_ereg_search
[49] => mb_ereg_search_pos
[50] => mb_ereg_search_regs
[51] => mb_ereg_search_init
[52] => mb_ereg_search_getregs
[53] => mb_ereg_search_getpos
[54] => mb_ereg_search_setpos
[55] => mbregex_encoding
[56] => mbereg
[57] => mberegi
[58] => mbereg_replace
[59] => mberegi_replace
[60] => mbsplit
[61] => mbereg_match
[62] => mbereg_search
[63] => mbereg_search_pos
[64] => mbereg_search_regs
[65] => mbereg_search_init
[66] => mbereg_search_getregs
[67] => mbereg_search_getpos
[68] => mbereg_search_setpos
)
*/
