This shows all the functions supported by the system, and custom functions
Array
(
    [internal] => Array
        (
            [0] => zend_version
            [1] => func_num_args
            [2] => func_get_arg
            [3] => func_get_args
            [4] => strlen
            [5] => strcmp
            [6] => strncmp
            [7] => strcasecmp
            [8] => strncasecmp
            [9] => each
            [10] => error_reporting
            [11] => define
            [12] => defined
            [13] => get_class
            [14] => get_called_class
            [15] => get_parent_class
            [16] => method_exists
            [17] => property_exists
            [18] => class_exists
            [19] => interface_exists
            [20] => trait_exists
            [21] => function_exists
            [22] => class_alias
            [23] => get_included_files
            [24] => get_required_files
            [25] => is_subclass_of
            [26] => is_a
            [27] => get_class_vars
            [28] => get_object_vars
            [29] => get_class_methods
            [30] => trigger_error
            [31] => user_error
            [32] => set_error_handler
            [33] => restore_error_handler
            [34] => set_exception_handler
            [35] => restore_exception_handler
            [36] => get_declared_classes
            [37] => get_declared_traits
            [38] => get_declared_interfaces
            [39] => get_defined_functions
            [40] => get_defined_vars
            [41] => create_function
            [42] => get_resource_type
            [43] => get_loaded_extensions
            [44] => extension_loaded
            [45] => get_extension_funcs
            [46] => get_defined_constants
            [47] => debug_backtrace
            [48] => debug_print_backtrace
            [49] => gc_collect_cycles
            [50] => gc_enabled
            [51] => gc_enable
            [52] => gc_disable
            [53] => strtotime
            [54] => date
            [55] => idate
            [56] => gmdate
            [57] => mktime
            [58] => gmmktime
            [59] => checkdate
            [60] => strftime
            [61] => gmstrftime
            [62] => time
            [63] => localtime
            [64] => getdate
            [65] => date_create
            [66] => date_create_immutable
            [67] => date_create_from_format
            [68] => date_create_immutable_from_format
            [69] => date_parse
            [70] => date_parse_from_format
            [71] => date_get_last_errors
            [72] => date_format
            [73] => date_modify
            [74] => date_add
            [75] => date_sub
            [76] => date_timezone_get
            [77] => date_timezone_set
            [78] => date_offset_get
            [79] => date_diff
            [80] => date_time_set
            [81] => date_date_set
            [82] => date_isodate_set
            [83] => date_timestamp_set
            [84] => date_timestamp_get
            [85] => timezone_open
            [86] => timezone_name_get
            [87] => timezone_name_from_abbr
            [88] => timezone_offset_get
            [89] => timezone_transitions_get
            [90] => timezone_location_get
            [91] => timezone_identifiers_list
            [92] => timezone_abbreviations_list
            [93] => timezone_version_get
            [94] => date_interval_create_from_date_string
            [95] => date_interval_format
            [96] => date_default_timezone_set
            [97] => date_default_timezone_get
            [98] => date_sunrise
            [99] => date_sunset
            [100] => date_sun_info
            [101] => ereg
            [102] => ereg_replace
            [103] => eregi
            [104] => eregi_replace
            [105] => split
            [106] => spliti
            [107] => sql_regcase
            [108] => libxml_set_streams_context
            [109] => libxml_use_internal_errors
            [110] => libxml_get_last_error
            [111] => libxml_clear_errors
            [112] => libxml_get_errors
            [113] => libxml_disable_entity_loader
            [114] => libxml_set_external_entity_loader
            [115] => openssl_get_cert_locations
            [116] => openssl_spki_new
            [117] => openssl_spki_verify
            [118] => openssl_spki_export
            [119] => openssl_spki_export_challenge
            [120] => openssl_pkey_free
            [121] => openssl_pkey_new
            [122] => openssl_pkey_export
            [123] => openssl_pkey_export_to_file
            [124] => openssl_pkey_get_private
            [125] => openssl_pkey_get_public
            [126] => openssl_pkey_get_details
            [127] => openssl_free_key
            [128] => openssl_get_privatekey
            [129] => openssl_get_publickey
            [130] => openssl_x509_read
            [131] => openssl_x509_free
            [132] => openssl_x509_parse
            [133] => openssl_x509_checkpurpose
            [134] => openssl_x509_check_private_key
            [135] => openssl_x509_export
            [136] => openssl_x509_fingerprint
            [137] => openssl_x509_export_to_file
            [138] => openssl_pkcs12_export
            [139] => openssl_pkcs12_export_to_file
            [140] => openssl_pkcs12_read
            [141] => openssl_csr_new
            [142] => openssl_csr_export
            [143] => openssl_csr_export_to_file
            [144] => openssl_csr_sign
            [145] => openssl_csr_get_subject
            [146] => openssl_csr_get_public_key
            [147] => openssl_digest
            [148] => openssl_encrypt
            [149] => openssl_decrypt
            [150] => openssl_cipher_iv_length
            [151] => openssl_sign
            [152] => openssl_verify
            [153] => openssl_seal
            [154] => openssl_open
            [155] => openssl_pbkdf2
            [156] => openssl_pkcs7_verify
            [157] => openssl_pkcs7_decrypt
            [158] => openssl_pkcs7_sign
            [159] => openssl_pkcs7_encrypt
            [160] => openssl_private_encrypt
            [161] => openssl_private_decrypt
            [162] => openssl_public_encrypt
            [163] => openssl_public_decrypt
            [164] => openssl_get_md_methods
            [165] => openssl_get_cipher_methods
            [166] => openssl_dh_compute_key
            [167] => openssl_random_pseudo_bytes
            [168] => openssl_error_string
            [169] => preg_match
            [170] => preg_match_all
            [171] => preg_replace
            [172] => preg_replace_callback
            [173] => preg_filter
            [174] => preg_split
            [175] => preg_quote
            [176] => preg_grep
            [177] => preg_last_error
            [178] => readgzfile
            [179] => gzrewind
            [180] => gzclose
            [181] => gzeof
            [182] => gzgetc
            [183] => gzgets
            [184] => gzgetss
            [185] => gzread
            [186] => gzopen
            [187] => gzpassthru
            [188] => gzseek
            [189] => gztell
            [190] => gzwrite
            [191] => gzputs
            [192] => gzfile
            [193] => gzcompress
            [194] => gzuncompress
            [195] => gzdeflate
            [196] => gzinflate
            [197] => gzencode
            [198] => gzdecode
            [199] => zlib_encode
            [200] => zlib_decode
            [201] => zlib_get_coding_type
            [202] => ob_gzhandler
            [203] => bcadd
            [204] => bcsub
            [205] => bcmul
            [206] => bcdiv
            [207] => bcmod
            [208] => bcpow
            [209] => bcsqrt
            [210] => bcscale
            [211] => bccomp
            [212] => bcpowmod
            [213] => bzopen
            [214] => bzread
            [215] => bzwrite
            [216] => bzflush
            [217] => bzclose
            [218] => bzerrno
            [219] => bzerrstr
            [220] => bzerror
            [221] => bzcompress
            [222] => bzdecompress
            [223] => jdtogregorian
            [224] => gregoriantojd
            [225] => jdtojulian
            [226] => juliantojd
            [227] => jdtojewish
            [228] => jewishtojd
            [229] => jdtofrench
            [230] => frenchtojd
            [231] => jddayofweek
            [232] => jdmonthname
            [233] => easter_date
            [234] => easter_days
            [235] => unixtojd
            [236] => jdtounix
            [237] => cal_to_jd
            [238] => cal_from_jd
            [239] => cal_days_in_month
            [240] => cal_info
            [241] => ctype_alnum
            [242] => ctype_alpha
            [243] => ctype_cntrl
            [244] => ctype_digit
            [245] => ctype_lower
            [246] => ctype_graph
            [247] => ctype_print
            [248] => ctype_punct
            [249] => ctype_space
            [250] => ctype_upper
            [251] => ctype_xdigit
            [252] => dba_open
            [253] => dba_popen
            [254] => dba_close
            [255] => dba_delete
            [256] => dba_exists
            [257] => dba_fetch
            [258] => dba_insert
            [259] => dba_replace
            [260] => dba_firstkey
            [261] => dba_nextkey
            [262] => dba_optimize
            [263] => dba_sync
            [264] => dba_handlers
            [265] => dba_list
            [266] => dba_key_split
            [267] => dom_import_simplexml
            [268] => exif_read_data
            [269] => read_exif_data
            [270] => exif_tagname
            [271] => exif_thumbnail
            [272] => exif_imagetype
            [273] => finfo_open
            [274] => finfo_close
            [275] => finfo_set_flags
            [276] => finfo_file
            [277] => finfo_buffer
            [278] => mime_content_type
            [279] => filter_input
            [280] => filter_var
            [281] => filter_input_array
            [282] => filter_var_array
            [283] => filter_list
            [284] => filter_has_var
            [285] => filter_id
            [286] => ftp_connect
            [287] => ftp_ssl_connect
            [288] => ftp_login
            [289] => ftp_pwd
            [290] => ftp_cdup
            [291] => ftp_chdir
            [292] => ftp_exec
            [293] => ftp_raw
            [294] => ftp_mkdir
            [295] => ftp_rmdir
            [296] => ftp_chmod
            [297] => ftp_alloc
            [298] => ftp_nlist
            [299] => ftp_rawlist
            [300] => ftp_systype
            [301] => ftp_pasv
            [302] => ftp_get
            [303] => ftp_fget
            [304] => ftp_put
            [305] => ftp_fput
            [306] => ftp_size
            [307] => ftp_mdtm
            [308] => ftp_rename
            [309] => ftp_delete
            [310] => ftp_site
            [311] => ftp_close
            [312] => ftp_set_option
            [313] => ftp_get_option
            [314] => ftp_nb_fget
            [315] => ftp_nb_get
            [316] => ftp_nb_continue
            [317] => ftp_nb_put
            [318] => ftp_nb_fput
            [319] => ftp_quit
            [320] => textdomain
            [321] => gettext
            [322] => _
            [323] => dgettext
            [324] => dcgettext
            [325] => bindtextdomain
            [326] => ngettext
            [327] => dngettext
            [328] => dcngettext
            [329] => bind_textdomain_codeset
            [330] => hash
            [331] => hash_file
            [332] => hash_hmac
            [333] => hash_hmac_file
            [334] => hash_init
            [335] => hash_update
            [336] => hash_update_stream
            [337] => hash_update_file
            [338] => hash_final
            [339] => hash_copy
            [340] => hash_algos
            [341] => hash_pbkdf2
            [342] => hash_equals
            [343] => mhash_keygen_s2k
            [344] => mhash_get_block_size
            [345] => mhash_get_hash_name
            [346] => mhash_count
            [347] => mhash
            [348] => iconv
            [349] => iconv_get_encoding
            [350] => iconv_set_encoding
            [351] => iconv_strlen
            [352] => iconv_substr
            [353] => iconv_strpos
            [354] => iconv_strrpos
            [355] => iconv_mime_encode
            [356] => iconv_mime_decode
            [357] => iconv_mime_decode_headers
            [358] => mb_convert_case
            [359] => mb_strtoupper
            [360] => mb_strtolower
            [361] => mb_language
            [362] => mb_internal_encoding
            [363] => mb_http_input
            [364] => mb_http_output
            [365] => mb_detect_order
            [366] => mb_substitute_character
            [367] => mb_parse_str
            [368] => mb_output_handler
            [369] => mb_preferred_mime_name
            [370] => mb_strlen
            [371] => mb_strpos
            [372] => mb_strrpos
            [373] => mb_stripos
            [374] => mb_strripos
            [375] => mb_strstr
            [376] => mb_strrchr
            [377] => mb_stristr
            [378] => mb_strrichr
            [379] => mb_substr_count
            [380] => mb_substr
            [381] => mb_strcut
            [382] => mb_strwidth
            [383] => mb_strimwidth
            [384] => mb_convert_encoding
            [385] => mb_detect_encoding
            [386] => mb_list_encodings
            [387] => mb_encoding_aliases
            [388] => mb_convert_kana
            [389] => mb_encode_mimeheader
            [390] => mb_decode_mimeheader
            [391] => mb_convert_variables
            [392] => mb_encode_numericentity
            [393] => mb_decode_numericentity
            [394] => mb_send_mail
            [395] => mb_get_info
            [396] => mb_check_encoding
            [397] => mb_regex_encoding
            [398] => mb_regex_set_options
            [399] => mb_ereg
            [400] => mb_eregi
            [401] => mb_ereg_replace
            [402] => mb_eregi_replace
            [403] => mb_ereg_replace_callback
            [404] => mb_split
            [405] => mb_ereg_match
            [406] => mb_ereg_search
            [407] => mb_ereg_search_pos
            [408] => mb_ereg_search_regs
            [409] => mb_ereg_search_init
            [410] => mb_ereg_search_getregs
            [411] => mb_ereg_search_getpos
            [412] => mb_ereg_search_setpos
            [413] => mbregex_encoding
            [414] => mbereg
            [415] => mberegi
            [416] => mbereg_replace
            [417] => mberegi_replace
            [418] => mbsplit
            [419] => mbereg_match
            [420] => mbereg_search
            [421] => mbereg_search_pos
            [422] => mbereg_search_regs
            [423] => mbereg_search_init
            [424] => mbereg_search_getregs
            [425] => mbereg_search_getpos
            [426] => mbereg_search_setpos
            [427] => posix_kill
            [428] => posix_getpid
            [429] => posix_getppid
            [430] => posix_getuid
            [431] => posix_setuid
            [432] => posix_geteuid
            [433] => posix_seteuid
            [434] => posix_getgid
            [435] => posix_setgid
            [436] => posix_getegid
            [437] => posix_setegid
            [438] => posix_getgroups
            [439] => posix_getlogin
            [440] => posix_getpgrp
            [441] => posix_setsid
            [442] => posix_setpgid
            [443] => posix_getpgid
            [444] => posix_getsid
            [445] => posix_uname
            [446] => posix_times
            [447] => posix_ctermid
            [448] => posix_ttyname
            [449] => posix_isatty
            [450] => posix_getcwd
            [451] => posix_mkfifo
            [452] => posix_mknod
            [453] => posix_access
            [454] => posix_getgrnam
            [455] => posix_getgrgid
            [456] => posix_getpwnam
            [457] => posix_getpwuid
            [458] => posix_getrlimit
            [459] => posix_get_last_error
            [460] => posix_errno
            [461] => posix_strerror
            [462] => posix_initgroups
            [463] => session_name
            [464] => session_module_name
            [465] => session_save_path
            [466] => session_id
            [467] => session_regenerate_id
            [468] => session_decode
            [469] => session_encode
            [470] => session_start
            [471] => session_destroy
            [472] => session_unset
            [473] => session_set_save_handler
            [474] => session_cache_limiter
            [475] => session_cache_expire
            [476] => session_set_cookie_params
            [477] => session_get_cookie_params
            [478] => session_write_close
            [479] => session_abort
            [480] => session_reset
            [481] => session_status
            [482] => session_register_shutdown
            [483] => session_commit
            [484] => shmop_open
            [485] => shmop_read
            [486] => shmop_close
            [487] => shmop_size
            [488] => shmop_write
            [489] => shmop_delete
            [490] => simplexml_load_file
            [491] => simplexml_load_string
            [492] => simplexml_import_dom
            [493] => use_soap_error_handler
            [494] => is_soap_fault
            [495] => socket_select
            [496] => socket_create
            [497] => socket_create_listen
            [498] => socket_create_pair
            [499] => socket_accept
            [500] => socket_set_nonblock
            [501] => socket_set_block
            [502] => socket_listen
            [503] => socket_close
            [504] => socket_write
            [505] => socket_read
            [506] => socket_getsockname
            [507] => socket_getpeername
            [508] => socket_connect
            [509] => socket_strerror
            [510] => socket_bind
            [511] => socket_recv
            [512] => socket_send
            [513] => socket_recvfrom
            [514] => socket_sendto
            [515] => socket_get_option
            [516] => socket_set_option
            [517] => socket_shutdown
            [518] => socket_last_error
            [519] => socket_clear_error
            [520] => socket_import_stream
            [521] => socket_sendmsg
            [522] => socket_recvmsg
            [523] => socket_cmsg_space
            [524] => socket_getopt
            [525] => socket_setopt
            [526] => spl_classes
            [527] => spl_autoload
            [528] => spl_autoload_extensions
            [529] => spl_autoload_register
            [530] => spl_autoload_unregister
            [531] => spl_autoload_functions
            [532] => spl_autoload_call
            [533] => class_parents
            [534] => class_implements
            [535] => class_uses
            [536] => spl_object_hash
            [537] => iterator_to_array
            [538] => iterator_count
            [539] => iterator_apply
            [540] => constant
            [541] => bin2hex
            [542] => hex2bin
            [543] => sleep
            [544] => usleep
            [545] => time_nanosleep
            [546] => time_sleep_until
            [547] => strptime
            [548] => flush
            [549] => wordwrap
            [550] => htmlspecialchars
            [551] => htmlentities
            [552] => html_entity_decode
            [553] => htmlspecialchars_decode
            [554] => get_html_translation_table
            [555] => sha1
            [556] => sha1_file
            [557] => md5
            [558] => md5_file
            [559] => crc32
            [560] => iptcparse
            [561] => iptcembed
            [562] => getimagesize
            [563] => getimagesizefromstring
            [564] => image_type_to_mime_type
            [565] => image_type_to_extension
            [566] => phpinfo
            [567] => phpversion
            [568] => phpcredits
            [569] => php_sapi_name
            [570] => php_uname
            [571] => php_ini_scanned_files
            [572] => php_ini_loaded_file
            [573] => strnatcmp
            [574] => strnatcasecmp
            [575] => substr_count
            [576] => strspn
            [577] => strcspn
            [578] => strtok
            [579] => strtoupper
            [580] => strtolower
            [581] => strpos
            [582] => stripos
            [583] => strrpos
            [584] => strripos
            [585] => strrev
            [586] => hebrev
            [587] => hebrevc
            [588] => nl2br
            [589] => basename
            [590] => dirname
            [591] => pathinfo
            [592] => stripslashes
            [593] => stripcslashes
            [594] => strstr
            [595] => stristr
            [596] => strrchr
            [597] => str_shuffle
            [598] => str_word_count
            [599] => str_split
            [600] => strpbrk
            [601] => substr_compare
            [602] => strcoll
            [603] => money_format
            [604] => substr
            [605] => substr_replace
            [606] => quotemeta
            [607] => ucfirst
            [608] => lcfirst
            [609] => ucwords
            [610] => strtr
            [611] => addslashes
            [612] => addcslashes
            [613] => rtrim
            [614] => str_replace
            [615] => str_ireplace
            [616] => str_repeat
            [617] => count_chars
            [618] => chunk_split
            [619] => trim
            [620] => ltrim
            [621] => strip_tags
            [622] => similar_text
            [623] => explode
            [624] => implode
            [625] => join
            [626] => setlocale
            [627] => localeconv
            [628] => nl_langinfo
            [629] => soundex
            [630] => levenshtein
            [631] => chr
            [632] => ord
            [633] => parse_str
            [634] => str_getcsv
            [635] => str_pad
            [636] => chop
            [637] => strchr
            [638] => sprintf
            [639] => printf
            [640] => vprintf
            [641] => vsprintf
            [642] => fprintf
            [643] => vfprintf
            [644] => sscanf
            [645] => fscanf
            [646] => parse_url
            [647] => urlencode
            [648] => urldecode
            [649] => rawurlencode
            [650] => rawurldecode
            [651] => http_build_query
            [652] => readlink
            [653] => linkinfo
            [654] => symlink
            [655] => link
            [656] => unlink
            [657] => exec
            [658] => system
            [659] => escapeshellcmd
            [660] => escapeshellarg
            [661] => passthru
            [662] => shell_exec
            [663] => proc_open
            [664] => proc_close
            [665] => proc_terminate
            [666] => proc_get_status
            [667] => proc_nice
            [668] => rand
            [669] => srand
            [670] => getrandmax
            [671] => mt_rand
            [672] => mt_srand
            [673] => mt_getrandmax
            [674] => getservbyname
            [675] => getservbyport
            [676] => getprotobyname
            [677] => getprotobynumber
            [678] => getmyuid
            [679] => getmygid
            [680] => getmypid
            [681] => getmyinode
            [682] => getlastmod
            [683] => base64_decode
            [684] => base64_encode
            [685] => password_hash
            [686] => password_get_info
            [687] => password_needs_rehash
            [688] => password_verify
            [689] => convert_uuencode
            [690] => convert_uudecode
            [691] => abs
            [692] => ceil
            [693] => floor
            [694] => round
            [695] => sin
            [696] => cos
            [697] => tan
            [698] => asin
            [699] => acos
            [700] => atan
            [701] => atanh
            [702] => atan2
            [703] => sinh
            [704] => cosh
            [705] => tanh
            [706] => asinh
            [707] => acosh
            [708] => expm1
            [709] => log1p
            [710] => pi
            [711] => is_finite
            [712] => is_nan
            [713] => is_infinite
            [714] => pow
            [715] => exp
            [716] => log
            [717] => log10
            [718] => sqrt
            [719] => hypot
            [720] => deg2rad
            [721] => rad2deg
            [722] => bindec
            [723] => hexdec
            [724] => octdec
            [725] => decbin
            [726] => decoct
            [727] => dechex
            [728] => base_convert
            [729] => number_format
            [730] => fmod
            [731] => inet_ntop
            [732] => inet_pton
            [733] => ip2long
            [734] => long2ip
            [735] => getenv
            [736] => putenv
            [737] => getopt
            [738] => sys_getloadavg
            [739] => microtime
            [740] => gettimeofday
            [741] => getrusage
            [742] => uniqid
            [743] => quoted_printable_decode
            [744] => quoted_printable_encode
            [745] => convert_cyr_string
            [746] => get_current_user
            [747] => set_time_limit
            [748] => header_register_callback
            [749] => get_cfg_var
            [750] => magic_quotes_runtime
            [751] => set_magic_quotes_runtime
            [752] => get_magic_quotes_gpc
            [753] => get_magic_quotes_runtime
            [754] => error_log
            [755] => error_get_last
            [756] => call_user_func
            [757] => call_user_func_array
            [758] => call_user_method
            [759] => call_user_method_array
            [760] => forward_static_call
            [761] => forward_static_call_array
            [762] => serialize
            [763] => unserialize
            [764] => var_dump
            [765] => var_export
            [766] => debug_zval_dump
            [767] => print_r
            [768] => memory_get_usage
            [769] => memory_get_peak_usage
            [770] => register_shutdown_function
            [771] => register_tick_function
            [772] => unregister_tick_function
            [773] => highlight_file
            [774] => show_source
            [775] => highlight_string
            [776] => php_strip_whitespace
            [777] => ini_get
            [778] => ini_get_all
            [779] => ini_set
            [780] => ini_alter
            [781] => ini_restore
            [782] => get_include_path
            [783] => set_include_path
            [784] => restore_include_path
            [785] => setcookie
            [786] => setrawcookie
            [787] => header
            [788] => header_remove
            [789] => headers_sent
            [790] => headers_list
            [791] => http_response_code
            [792] => connection_aborted
            [793] => connection_status
            [794] => ignore_user_abort
            [795] => parse_ini_file
            [796] => parse_ini_string
            [797] => is_uploaded_file
            [798] => move_uploaded_file
            [799] => gethostbyaddr
            [800] => gethostbyname
            [801] => gethostbynamel
            [802] => gethostname
            [803] => dns_check_record
            [804] => checkdnsrr
            [805] => dns_get_mx
            [806] => getmxrr
            [807] => dns_get_record
            [808] => intval
            [809] => floatval
            [810] => doubleval
            [811] => strval
            [812] => boolval
            [813] => gettype
            [814] => settype
            [815] => is_null
            [816] => is_resource
            [817] => is_bool
            [818] => is_long
            [819] => is_float
            [820] => is_int
            [821] => is_integer
            [822] => is_double
            [823] => is_real
            [824] => is_numeric
            [825] => is_string
            [826] => is_array
            [827] => is_object
            [828] => is_scalar
            [829] => is_callable
            [830] => pclose
            [831] => popen
            [832] => readfile
            [833] => rewind
            [834] => rmdir
            [835] => umask
            [836] => fclose
            [837] => feof
            [838] => fgetc
            [839] => fgets
            [840] => fgetss
            [841] => fread
            [842] => fopen
            [843] => fpassthru
            [844] => ftruncate
            [845] => fstat
            [846] => fseek
            [847] => ftell
            [848] => fflush
            [849] => fwrite
            [850] => fputs
            [851] => mkdir
            [852] => rename
            [853] => copy
            [854] => tempnam
            [855] => tmpfile
            [856] => file
            [857] => file_get_contents
            [858] => file_put_contents
            [859] => stream_select
            [860] => stream_context_create
            [861] => stream_context_set_params
            [862] => stream_context_get_params
            [863] => stream_context_set_option
            [864] => stream_context_get_options
            [865] => stream_context_get_default
            [866] => stream_context_set_default
            [867] => stream_filter_prepend
            [868] => stream_filter_append
            [869] => stream_filter_remove
            [870] => stream_socket_client
            [871] => stream_socket_server
            [872] => stream_socket_accept
            [873] => stream_socket_get_name
            [874] => stream_socket_recvfrom
            [875] => stream_socket_sendto
            [876] => stream_socket_enable_crypto
            [877] => stream_socket_shutdown
            [878] => stream_socket_pair
            [879] => stream_copy_to_stream
            [880] => stream_get_contents
            [881] => stream_supports_lock
            [882] => fgetcsv
            [883] => fputcsv
            [884] => flock
            [885] => get_meta_tags
            [886] => stream_set_read_buffer
            [887] => stream_set_write_buffer
            [888] => set_file_buffer
            [889] => stream_set_chunk_size
            [890] => set_socket_blocking
            [891] => stream_set_blocking
            [892] => socket_set_blocking
            [893] => stream_get_meta_data
            [894] => stream_get_line
            [895] => stream_wrapper_register
            [896] => stream_register_wrapper
            [897] => stream_wrapper_unregister
            [898] => stream_wrapper_restore
            [899] => stream_get_wrappers
            [900] => stream_get_transports
            [901] => stream_resolve_include_path
            [902] => stream_is_local
            [903] => get_headers
            [904] => stream_set_timeout
            [905] => socket_set_timeout
            [906] => socket_get_status
            [907] => realpath
            [908] => fnmatch
            [909] => fsockopen
            [910] => pfsockopen
            [911] => pack
            [912] => unpack
            [913] => get_browser
            [914] => crypt
            [915] => opendir
            [916] => closedir
            [917] => chdir
            [918] => getcwd
            [919] => rewinddir
            [920] => readdir
            [921] => dir
            [922] => scandir
            [923] => glob
            [924] => fileatime
            [925] => filectime
            [926] => filegroup
            [927] => fileinode
            [928] => filemtime
            [929] => fileowner
            [930] => fileperms
            [931] => filesize
            [932] => filetype
            [933] => file_exists
            [934] => is_writable
            [935] => is_writeable
            [936] => is_readable
            [937] => is_executable
            [938] => is_file
            [939] => is_dir
            [940] => is_link
            [941] => stat
            [942] => lstat
            [943] => chown
            [944] => chgrp
            [945] => lchown
            [946] => lchgrp
            [947] => chmod
            [948] => touch
            [949] => clearstatcache
            [950] => disk_total_space
            [951] => disk_free_space
            [952] => diskfreespace
            [953] => realpath_cache_size
            [954] => realpath_cache_get
            [955] => mail
            [956] => ezmlm_hash
            [957] => openlog
            [958] => syslog
            [959] => closelog
            [960] => lcg_value
            [961] => metaphone
            [962] => ob_start
            [963] => ob_flush
            [964] => ob_clean
            [965] => ob_end_flush
            [966] => ob_end_clean
            [967] => ob_get_flush
            [968] => ob_get_clean
            [969] => ob_get_length
            [970] => ob_get_level
            [971] => ob_get_status
            [972] => ob_get_contents
            [973] => ob_implicit_flush
            [974] => ob_list_handlers
            [975] => ksort
            [976] => krsort
            [977] => natsort
            [978] => natcasesort
            [979] => asort
            [980] => arsort
            [981] => sort
            [982] => rsort
            [983] => usort
            [984] => uasort
            [985] => uksort
            [986] => shuffle
            [987] => array_walk
            [988] => array_walk_recursive
            [989] => count
            [990] => end
            [991] => prev
            [992] => next
            [993] => reset
            [994] => current
            [995] => key
            [996] => min
            [997] => max
            [998] => in_array
            [999] => array_search
            [1000] => extract
            [1001] => compact
            [1002] => array_fill
            [1003] => array_fill_keys
            [1004] => range
            [1005] => array_multisort
            [1006] => array_push
            [1007] => array_pop
            [1008] => array_shift
            [1009] => array_unshift
            [1010] => array_splice
            [1011] => array_slice
            [1012] => array_merge
            [1013] => array_merge_recursive
            [1014] => array_replace
            [1015] => array_replace_recursive
            [1016] => array_keys
            [1017] => array_values
            [1018] => array_count_values
            [1019] => array_column
            [1020] => array_reverse
            [1021] => array_reduce
            [1022] => array_pad
            [1023] => array_flip
            [1024] => array_change_key_case
            [1025] => array_rand
            [1026] => array_unique
            [1027] => array_intersect
            [1028] => array_intersect_key
            [1029] => array_intersect_ukey
            [1030] => array_uintersect
            [1031] => array_intersect_assoc
            [1032] => array_uintersect_assoc
            [1033] => array_intersect_uassoc
            [1034] => array_uintersect_uassoc
            [1035] => array_diff
            [1036] => array_diff_key
            [1037] => array_diff_ukey
            [1038] => array_udiff
            [1039] => array_diff_assoc
            [1040] => array_udiff_assoc
            [1041] => array_diff_uassoc
            [1042] => array_udiff_uassoc
            [1043] => array_sum
            [1044] => array_product
            [1045] => array_filter
            [1046] => array_map
            [1047] => array_chunk
            [1048] => array_combine
            [1049] => array_key_exists
            [1050] => pos
            [1051] => sizeof
            [1052] => key_exists
            [1053] => assert
            [1054] => assert_options
            [1055] => version_compare
            [1056] => ftok
            [1057] => str_rot13
            [1058] => stream_get_filters
            [1059] => stream_filter_register
            [1060] => stream_bucket_make_writeable
            [1061] => stream_bucket_prepend
            [1062] => stream_bucket_append
            [1063] => stream_bucket_new
            [1064] => output_add_rewrite_var
            [1065] => output_reset_rewrite_vars
            [1066] => sys_get_temp_dir
            [1067] => msg_get_queue
            [1068] => msg_send
            [1069] => msg_receive
            [1070] => msg_remove_queue
            [1071] => msg_stat_queue
            [1072] => msg_set_queue
            [1073] => msg_queue_exists
            [1074] => sem_get
            [1075] => sem_acquire
            [1076] => sem_release
            [1077] => sem_remove
            [1078] => shm_attach
            [1079] => shm_remove
            [1080] => shm_detach
            [1081] => shm_put_var
            [1082] => shm_has_var
            [1083] => shm_get_var
            [1084] => shm_remove_var
            [1085] => token_get_all
            [1086] => token_name
            [1087] => wddx_serialize_value
            [1088] => wddx_serialize_vars
            [1089] => wddx_packet_start
            [1090] => wddx_packet_end
            [1091] => wddx_add_vars
            [1092] => wddx_deserialize
            [1093] => xml_parser_create
            [1094] => xml_parser_create_ns
            [1095] => xml_set_object
            [1096] => xml_set_element_handler
            [1097] => xml_set_character_data_handler
            [1098] => xml_set_processing_instruction_handler
            [1099] => xml_set_default_handler
            [1100] => xml_set_unparsed_entity_decl_handler
            [1101] => xml_set_notation_decl_handler
            [1102] => xml_set_external_entity_ref_handler
            [1103] => xml_set_start_namespace_decl_handler
            [1104] => xml_set_end_namespace_decl_handler
            [1105] => xml_parse
            [1106] => xml_parse_into_struct
            [1107] => xml_get_error_code
            [1108] => xml_error_string
            [1109] => xml_get_current_line_number
            [1110] => xml_get_current_column_number
            [1111] => xml_get_current_byte_index
            [1112] => xml_parser_free
            [1113] => xml_parser_set_option
            [1114] => xml_parser_get_option
            [1115] => utf8_encode
            [1116] => utf8_decode
            [1117] => xmlwriter_open_uri
            [1118] => xmlwriter_open_memory
            [1119] => xmlwriter_set_indent
            [1120] => xmlwriter_set_indent_string
            [1121] => xmlwriter_start_comment
            [1122] => xmlwriter_end_comment
            [1123] => xmlwriter_start_attribute
            [1124] => xmlwriter_end_attribute
            [1125] => xmlwriter_write_attribute
            [1126] => xmlwriter_start_attribute_ns
            [1127] => xmlwriter_write_attribute_ns
            [1128] => xmlwriter_start_element
            [1129] => xmlwriter_end_element
            [1130] => xmlwriter_full_end_element
            [1131] => xmlwriter_start_element_ns
            [1132] => xmlwriter_write_element
            [1133] => xmlwriter_write_element_ns
            [1134] => xmlwriter_start_pi
            [1135] => xmlwriter_end_pi
            [1136] => xmlwriter_write_pi
            [1137] => xmlwriter_start_cdata
            [1138] => xmlwriter_end_cdata
            [1139] => xmlwriter_write_cdata
            [1140] => xmlwriter_text
            [1141] => xmlwriter_write_raw
            [1142] => xmlwriter_start_document
            [1143] => xmlwriter_end_document
            [1144] => xmlwriter_write_comment
            [1145] => xmlwriter_start_dtd
            [1146] => xmlwriter_end_dtd
            [1147] => xmlwriter_write_dtd
            [1148] => xmlwriter_start_dtd_element
            [1149] => xmlwriter_end_dtd_element
            [1150] => xmlwriter_write_dtd_element
            [1151] => xmlwriter_start_dtd_attlist
            [1152] => xmlwriter_end_dtd_attlist
            [1153] => xmlwriter_write_dtd_attlist
            [1154] => xmlwriter_start_dtd_entity
            [1155] => xmlwriter_end_dtd_entity
            [1156] => xmlwriter_write_dtd_entity
            [1157] => xmlwriter_output_memory
            [1158] => xmlwriter_flush
            [1159] => zip_open
            [1160] => zip_close
            [1161] => zip_read
            [1162] => zip_entry_open
            [1163] => zip_entry_close
            [1164] => zip_entry_read
            [1165] => zip_entry_filesize
            [1166] => zip_entry_name
            [1167] => zip_entry_compressedsize
            [1168] => zip_entry_compressionmethod
            [1169] => fastcgi_finish_request
            [1170] => getallheaders
            [1171] => apache_request_headers
            [1172] => pdo_drivers
            [1173] => json_encode
            [1174] => json_decode
            [1175] => json_last_error
            [1176] => json_last_error_msg
            [1177] => readline
            [1178] => readline_info
            [1179] => readline_add_history
            [1180] => readline_clear_history
            [1181] => readline_read_history
            [1182] => readline_write_history
            [1183] => readline_completion_function
            [1184] => readline_callback_handler_install
            [1185] => readline_callback_read_char
            [1186] => readline_callback_handler_remove
            [1187] => readline_redisplay
            [1188] => readline_on_new_line
            [1189] => opcache_reset
            [1190] => opcache_invalidate
            [1191] => opcache_compile_file
            [1192] => opcache_is_script_cached
            [1193] => opcache_get_configuration
            [1194] => opcache_get_status
            [1195] => dl
        )

    [user] => Array
        (
            [0] => memory_usage
            [1] => microtime_float
            [2] => formatsize
            [3] => valid_email
            [4] => show
            [5] => isfun
            [6] => isfun1
            [7] => test_int
            [8] => test_float
            [9] => test_io
            [10] => getcoreinformation
            [11] => getcpupercentages
            [12] => makeimageurl
            [13] => sys_linux
            [14] => sys_freebsd
            [15] => get_key
            [16] => find_command
            [17] => do_command
            [18] => sys_windows
            [19] => getwmi
            [20] => bar
        )

)