在闹钟响起时从pending intent获取requestCode

当闹钟响起时，如何从 Receiver 类或者 Activity 类的 pending intent 中获取 requestCode？

alarmMgr= (AlarmManager)getSystemService(Context.ALARM_SERVICE);
                Intent intent = new Intent(this, BroadcastReceiver_Class.class);
                /*intent.putExtra("alarm_time_minutes", minutes);*/
                pendingIntent = PendingIntent.getBroadcast(this, requestCode, intent,requestCode);
                alarmMgr.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), pendingIntent);

把requestCode放到intent里不就行了？