lldb fails to print variable values with "error: reference to 'id' is ambiguous"

Solution 1:

I found one workaround:

Use 'Edit scheme' under the 'Product' menu, select 'Run' in the left bar, the 'Info' tab, and change the Debugger to gdb (this does not apply to xcode 5, which no longer has gdb).

Apparently Apple thought they'd fixed this bug in xcode 4.3.1, but it still happens. I submitted some extra debug information they requested, so I'm hoping it'll be fixed for the next release of xcode. It's still failing in 4.3.2. See https://devforums.apple.com/message/623694 for an update from Apple.

UPDATE

I've tried various cases I was having trouble with, and they all seem to be working fine with lldb in Xcode 4.4.1 - hence I highly recommend upgrading if you're having this problem.

Solution 2:

Try with following expression,

p self.view.bounds.size.width

or use,

po self.view

p - Print is only uses to print normal/simple values while, po - Print Object works same as NSLog to print value of an object

Solution 3:

Use Edit scheme under the 'Product' menu, select 'Run' in the left bar, the 'Info' tab, and change the Debugger to gdb.

Product>Edit Scheme>Run(Schemes)>Build Configuration it has three options (Some might see only two 1, 2) 1. Debug 2. Release 3. AdHoc

Just cross check if it is set to Debug if not then make it Debug.

This was the mistake I was doing

Solution 4:

(Xcode5) This is not really a direct answer to the original question, but I think it may be relevant and I would hate to think anyone else wastes hours as I did tracking it down. The problem I had was that no variable values were being shown in the debug window.

I checked the invocation that was actually being given to the compiler, and found that it was being optimized with -Os despite every project and target in the workspace being explicitly set to -O0, and the settings mentioned in other answers here all being set to Debug. After much searching I found that there is an option in the 'Info' section of each project called "Use xxx for command-line builds" where xxx is Debug/Release or whatever configurations are available. According to the tooltip description, this option should only affect builds done via command-line with the xcodebuild tool (which is a bit strange because that tool is perfectly capable of selecting which scheme to use as a command-line option). Anyway, changing this option to Debug finally got the IDE to tell the compiler I wanted -O0 and -g. I do not recall this ever happening with Xcode4, with the same workspace.

I should also add, that you might want to do a clean before changing this setting. I changed it without cleaning, and suddenly some of my header files were not being found (it seemed that pre-compiled headers were not being generated correctly). After another hour or so of stabbing in the dark, I found that if I first set the above-mentioned option back to Release and did a clean, then I could set it to Debug and build successfully.

Does anybody know if the Xcode development team actually use it themselves? I get the distinct impression that they do not.