问题
I have a method which returns a block. I want to add a breakpoint inside the block. In Xcode adding a breakpoint on a line that's inside the block causes execution to pause when the method is returned and not when the block is executed. How do I add a breakpoint inside a block?
回答1:
I had the same difficulty, until I tried using Xcode 4's LLDB debugger (go to Product>Edit Scheme to turn it on). Perhaps you'll have better luck with it.
回答2:
From the documentation
You can set breakpoints and single step into blocks. You can invoke a block from within a GDB session using invoke-block, as illustrated in this example:
$ invoke-block myBlock 10 20
If you want to pass in a C string, you must quote it. For example, to pass this string into the doSomethingWithString block, you would write the following:
$ invoke-block doSomethingWithString "\"this string\""
来源：https://stackoverflow.com/questions/5077459/in-xcode-how-do-i-add-a-breakpoint-inside-a-block