Xcode's Debugger

The debugger is the program that you write between the program and the operating system, it can interrupt your program, so that it stops running, so you can check the program data, and even modify the program.

A breakpoint is where the debugger should stop running the program and let you see where the program is running.

The debugger used by Xcode is Gdb,gdb is part of the GNU project and it can be used on many different platforms. If you want, you can use it from the command line. GDB has a complete documentation system, although its documentation is somewhat difficult to understand and several versions of the GDB tutorial are circulating on the web.

Xcode's Debugger