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I have a simple question about debugging on Xcode and GDB.
I often run into an error:
unrecognized selector sent to instance 0x1081ad0 which makes the program load into GDB. Is there an easy way to examine what instance is located in that memory from GDB?
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When your app pauses at a breakpoint, hover over a variable in your source code to view its current value. If the variable is an image or other type that isn't expressible as text, click the Quick Look button at the upper-right to see a preview of the variable.
Right click in the local variables window to see the "Watch Expression" menu command. Type the variable name and the variable will be added.
When you run an application in Xcode, the debugger is automatically started and attached to the process of the application. Click the Run button in the top left or press Command + R. From the moment the application is up and running, we can start inspecting the process and, if necessary, debug it.
Evaluate a C/ObjC/C++ expression in the current program context, using user defined variables and variables currently in scope. This command takes 'raw' input (no need to quote stuff). -G <gdb-format> ( --gdb-format <gdb-format> ) Specify a format using a GDB format specifier string.
po 0x1081ad0
po = Print Object. You can even call methods, like
po [myArray objectAtIndex:0]
Note that it only works on objects, so
po 1
will crash your program.
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