PHP naming conventions? [closed]

Question

I'm coding smt right now, and am a little bit peeved by the fact that PHP sometimes calls its functions with underscore, and sometimes as one word. What's up with that?

Example:

int strlen(string $str)

and

bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

I'm hoping that there is a good reason for this, and would really like to know what it is.

Answer 1

Quoted from: 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