CODEWITHSUNDEEP
iphonexcode
Crystal
Crystal

Reputation: 29518

Xcode 4, using breakpoints to log or po an object

I'm trying to figure out how to use the log or debug commands in adding actions to a breakpoint. I can't seem to figure it out. For something like this:

double currentZoom = [self getZoomScale];

How do I print out the currentZoom? I tried using log as my action, and then doing

currentZoom: @(double)currentZoom@ // this didn't work

currentZoom: @(double)[self getZoomScale]@ // also didn't work

Can someone help me out with this and any other info I may need to log information with breakpoints?

And also a simple example for po an object. Does po always po the description (as in you have to have overridden the description method? Thanks.

Upvotes: 2

Views: 1069

Answers (3)

Berik
Berik

Reputation: 8143

You can make the breakpoint execute debugger commands.

Open the edit breakpoint pane:

edit breakpoint pane.

Then type a debugger command (selecting "Automatically continue after evaluating" is advised).

To insert some context around the automated debugger commands, you can add another debugger action of type "Log Message". The "Log Message" action is not capable of inspecting variables itself.

NSLog() is probably easier to implement, but requires you to change the code you are debugging.

Upvotes: 1

Jesse Black
Jesse Black

Reputation: 7986

I do not know how to add actions to a breakpoint. (I am interested in seeing it in any other answers offered)

The gdb syntax for printing objects is

po objectName

The gdb syntax for printing C variables is

print (int) intNum
print (float) floatNum

Upvotes: 0

ferostar
ferostar

Reputation: 7082

If you want to print your double with NSLog, add the following line:

NSLog(@"%f", currentZoom);

Now, if you want to use the debugger console...

If you want to print currentZoom in the console, you don't need po. Plain p would be enough.This is, type

p currentZoom

and it's going to show you currentZoom's value. po is for objects. Let's say you wrap currentZoom in an NSNumber. 

NSNumber currentZoomNumber = [NSNumber numberWithDouble:currentZoom];

Then, to print the value, you would have to do 

po currentZoomNumber

Like i said, po is to print objects, it means print object. So you can use it to print any type of object, from NSStrings and NSNumbers to NSDictionaries and NSManagedObjects.

Upvotes: 3

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