public function setRunnable( $_runnable ) {
		if( self::runnableOk( $_runnable ) ) {
			$this->runnable = $_runnable;
		}
		else {
			throw new Exception( $this->getError( Thread::FUNCTION_NOT_CALLABLE ), Thread::FUNCTION_NOT_CALLABLE );
		}
	}
public function setRunnable( $_runnable ) {
		if( self::runnableOk( $_runnable ) ) {
			$this->runnable = $_runnable;
		}
		else {
			throw new Exception( $this->getError( Thread::FUNCTION_NOT_CALLABLE ), Thread::FUNCTION_NOT_CALLABLE );
		}
	}
public function setRunnable ( $ _runnable ) { if ( self :: runnableOk ( $ _runnable ) ) { $ this -> runnable = $ _runnable ; } else { throw new Exception ( $ this -> getError ( Thread :: FUNCTION_NOT_CALLABLE ) , Thread :: FUNCTION_NOT_CALLABLE ) ; } }
sets the callback

@param callback $_runnable
@return callback
sets the callback