WP::build_query_string()

	public function build_query_string() {
		$this->query_string = '';
		foreach ( (array) array_keys($this->query_vars) as $wpvar) {
			if ( '' != $this->query_vars[$wpvar] ) {
				$this->query_string .= (strlen($this->query_string) < 1) ? '' : '&';
				if ( !is_scalar($this->query_vars[$wpvar]) ) // Discard non-scalars.
					continue;
				$this->query_string .= $wpvar . '=' . rawurlencode($this->query_vars[$wpvar]);
			}
		}

		if ( has_filter( 'query_string' ) ) {  // Don't bother filtering and parsing if no plugins are hooked in.
			/**
			 * Filters the query string before parsing.
			 *
			 * @since WP-1.5.0
			 * @deprecated WP-2.1.0 Use 'query_vars' or 'request' filters instead.
			 *
			 * @param string $query_string The query string to modify.
			 */
			$this->query_string = apply_filters( 'query_string', $this->query_string );
			parse_str($this->query_string, $this->query_vars);
		}
	}