Resource Types
URL Functions
URLs
PHP Manual

# Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

The following constants are meant to be used with parse_url() and are available since PHP 5.1.2.

`PHP_URL_SCHEME` (integer)
`PHP_URL_HOST` (integer)
  Outputs the hostname of the URL parsed.
`PHP_URL_PORT` (integer)
  Outputs the port of the URL parsed.
`PHP_URL_USER` (integer)
  Outputs the user of the URL parsed.
`PHP_URL_PASS` (integer)
  Outputs the password of the URL parsed.
`PHP_URL_PATH` (integer)
  Outputs the path of the URL parsed.
`PHP_URL_QUERY` (integer)
  Outputs the query string of the URL parsed.
`PHP_URL_FRAGMENT` (integer)
  Outputs the fragment (string after the hashmark #) of the URL parsed.

The following constants are meant to be used with http_build_query().

`PHP_QUERY_RFC1738` (integer)
  Encoding is performed per » RFC 1738 and the application/x-www-form-urlencoded media type, which implies that spaces are encoded as plus (+) signs.
`PHP_QUERY_RFC3986` (integer)
  Encoding is performed according to » RFC 3986, and spaces will be percent encoded (%20).

Resource Types
URL Functions
URLs
PHP Manual