Frame variable 为什么没有打印输出啊?

The most convenient way to inspect a frame’s arguments and local variables is to use the “frame variable” command:
帮助里有,但为什么我这边不打印输出任何东西?这么重要的一个功能。我的是xcode 5.0.2
(lldb) frame variable
self = (SKTGraphicView *) 0x0000000100208b40
_cmd = (struct objc_selector *) 0x000000010001bae1
sender = (id) 0x00000001001264e0
selection = (NSArray *) 0x00000001001264e0
i = (NSUInteger) 0x00000001001264e0
c = (NSUInteger) 0x00000001001253b0
As you see above, if you don’t specify any variable names, all arguments and locals will be shown. If you call “frame variable” passing in the names of a particular local(s), only those variables will be printed. For instance:

(lldb) frame variable self
(SKTGraphicView *) self = 0x0000000100208b40