Xcode debugger sometimes doesn't display variable values?

Question

This happens to me pretty often. For example, right now I have the debugger stopped at a breakpoint in a method . . . and it isn\'t displaying any variable values at all.

Answer 1

You can get the value of any variable in the console by writing:

po name_of_an_objectCVar

or

print name_of_a_cVar

Answer 2

I've had the same issue and I fixed it by reinstalling all Pods. Just delete them and install again.

Answer 3

I figured out why it is not working in XCode 4.6 - all of the variables in my object, self, were declared in the .m file instead of the .h. When I moved one of them back to the .h file, it showed up in the debugger. Sounds like a bug with XCode in that it cannot "see" variables declared in the implementation file.

Answer 4

Had the same issue using Xcode 6.4 running the app on device. Running on simulator will show all variables on debugging variables panel.

Answer 5

There is a situation I have seen where Xcode can't cope with return value optimisation (RVO) -- if the compiler decides to apply RVO to a variable then it may not appear in the variables list. You can disable this in g++ and clang with the compiler flag -fno-elide-constructors

See also Understanding eliding rules with regard to c++11

Answer 6

The most common reason for this is that you're trying to debug code compiled with optimisation enabled and/or no debug symbols. Typically this will be because you're trying to debug a Release build rather than a Debug build but it can also happen with Debug builds if you've made inappropriate changes to the Debug build settings.

Another less common possibility is that you've hosed the stack.