(PHP 4, PHP 5, PHP 7) Checks if or where headers have been sent

(PHP 5 >= 5.1.0, PHP 7) Converts a packed internet address to a human readable representation

(PHP 5 >= 5.3.0, PHP 7) Remove previously set headers

(PHP 4, PHP 5, PHP 7) Open connection to system logger

(PHP 4, PHP 5, PHP 7) Get Internet service which corresponds to port and protocol

(PHP 4, PHP 5, PHP 7) Get protocol name associated with protocol number

(PHP 5, PHP 7) Alias of

(PHP 4, PHP 5, PHP 7) Close connection to system logger

(PHP 4, PHP 5, PHP 7) Get the IPv4 address corresponding to a given Internet host name

(PHP 5 >= 5.1.0, PHP 7) Converts a human readable IP address to its packed in_addr representation