CODEWITHSUNDEEP
ioscocoa-touchdebugginggdblldb
Chaitanya Gupta
Chaitanya Gupta

Reputation: 4053

Unable to set a watchpoint in either gdb or lldb

I am trying to set a watchpoint while debugging my app on the device. I am unable to set it on either gdb or lldb.

On lldb, I don't see the watchpoint set option in the debugger even though this page mentioned that it exists. When I try to run watchpoint set, lldb tells me that the command is not valid.

On gdb, I do get to set the watchpoint (using watch var), but when I try to continue execution I get this:

Can't set hardware watchpoints without the 'Z2' (write-watchpoint) packet.

I see no further output in the gdb window nor do I think I can interact with it. The app also remains hung at this point.

I am using Xcode 4.3.2 (4E2002) on OS X Lion. I tried setting the watchpoint on devices with iOS 5.1 and iOS 5.0.1 but encounter the same problem on both.

Upvotes: 5

Views: 2334

Answers (2)

Jason Molenda
Jason Molenda

Reputation: 15425

Before Xcode 4.5, watchpoints were not supported for iOS development with either lldb or gdb.

With Xcode 4.5, they are supported for iOS and Mac OS X debugging with lldb.

In Xcode, in the locals window, you can right-click/control-click on a variable and there will be an option to set a watchpoint on it. From the debugger console, to add a watchpoint on a variable called foo, you can do

(lldb) watchpoint set variable foo

the shortest unambiguous command is always valid in lldb so this would do the same thing,

(lldb) w s v foo

The current x86 and arm cpus only support 4 watchpoints being set simultaneously.

Upvotes: 7

RPM
RPM

Reputation: 3436

I read this somewhere in the Apple Dev Forums : "The set command exists in the trunk version but not in the Xcode version yet."

I am also stuck with this problem where I want to keep a watch on a variable and see where its value changes...

Upvotes: 0

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