Source Reference:

• Component: bbPress :: bbp-user

  File: /bbp-includes/bbp-user-template.php :: Trac Source Line: 59

  		// Maybe fallback on the current_user ID
  		elseif ( ( true == $current_user_fallback ) && !empty( $bbp->current_user->ID ) )
  			$bbp_user_id = $bbp->current_user->ID;
  
  		// Failsafe
  		else
  			$bbp_user_id = get_query_var( 'bbp_user_id' );
  
  		return apply_filters( 'bbp_get_user_id', (int) $bbp_user_id );
  	}
  
  /**
   * Output ID of current user
   *
   * @since bbPress (r2574)
   *
   * @uses bbp_get_current_user_id() To get the current user id
   */
  function bbp_current_user_id() {