引用自:
http://tnx.nl/php.html
PHP has inconsistent function naming
There is no apparent system in underscore(s) versus no underscore(s):
underscore no underscore:
stream_get_line readline
disk_free_space diskfreespace
is_object isset
mcal_day_of_week jddayofweek
set_error_handler setlocale
snmp_get_quick_print snmpget
get_browser getallheaders
base64_encode urlencode
image_type_to_mime_type imagetypes
msql_num_fields mysql_numfields
php_uname phpversion
strip_tags stripslashes
bind_textdomain_codeset bindtextdomain
cal_to_jd gregoriantojd
str_rot13 strpos