xcode debugger value of expression

In XCode, I insert a breakpoint at some line..

Say that line is:

abc = [books valueForKey:@"OfficialName"];
x = [appDelegate.books count];

My question is in the debugger, if I hover over say abc, it will display the value

But if I want to see the runtime value of an expression say "appDelegate.books count"

it does not show the value. How can I get the value of this expression 开发者_Go百科like a normal var ?

---

You can determine variable value using debugger console:

print (int) [arr count]

or use command po to print object's description

po objectName

---

This is somewhat unorthodox, but in order to find what you get in that for loop (see hmthur's comment in my other answer):

for (x=0;x<[arr count];x++)

Firstly, spread the loop over three seperate lines, so that you can debug step them one bit at a time:

for (x = 0;
     x < [arr count];
     x++)

Now put a breakpoint at the start of the for loop.

Step down so that x < [arr count] has been executed, but not the x++

Now in the watch window of the debugger, open up the registers group.

The result returned by [arr count] will be present in the $eax register.

This is most unorthodox, don't rely on it for developing life-critical software! Stick with my original answer in the interests of sanity.

---

It's not a variable, it's a message. But the answer will be stored in x, so hover over that instead.