Saturday, September 18, 2010

how to handle "Timed out fetching data. Variable display may be inaccurate." in Xcode while running GDB

I've been getting this error message in the debugger console of Xcode, while trying to debug some iPhone apps. At the same time it appears that GDB is freezing, after hitting a breakpoint and trying to step through the code, with the app being debugged eating up the available CPU juice.

Even if my app were very buggy, this still wouldn't be a reason to hang GDB, so I was starting to suspect that it may be a GDB issue. I discovered that if I moved my breakpoints the problem would disappear.

For example in the screenshot below, if I set the breakpoint anywhere on the lines 30-34 the problem appears, if I set it to line 36 the problem goes away.

While I don't know the root cause of this, a workaround is to move your breakpoint past the trouble zone.

1 comment:

Unknown said...

Although I'm aware of this problem, I tended to ignore it by relaunching debugger session. But today I had a chance to figure out the reason and a solution.

I guess that you found a solution already, because this post is written in 2010.

But just in case, I would like to write the solution here.

If you use Xcode 3.x. unselect Run->Variables View->Use Formatters

I use Xcode 4 at home, but here at work I have Xcode 3. but solution will be same although the menu item can be somewhere else if any.