Information Technology Reference
In-Depth Information
To use the zombies feature, follow these steps:
1.
Select Product
⇒
Proile in the main Xcode menu.
2.
Choose the Zombies instrument, as shown in Figure 16.20.
CAUTION
In iOS, the Zombies instrument is available only in the Simulator. It isn't included in the templates for an iOS
device.
3.
Wait for Instruments to load, and begin recording.
4.
Authenticate when asked to.
The test app crashes almost immediately, and it can take a while for Instruments to catch up. Don't worry if
you see the spinning beach ball while this happens; Instruments is working toward a useful display.
Figure 16.20
Selecting the Zombies instrument
Eventually, you see the display in Figure 16.21. The zombie event is tagged with a small red flag at the top of
the time line and a floating pop-up that includes a short summary of the zombie event. The detail pane shows
the history of the object and the reference count history of the history. In this example, the reference count his-
tory is very simple: The object is created, released, and released again. In a practical project, this history can be
longer and more complex.
