Debugging with GDB: Finish Breakpoints in Python

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#### 23.3.2.32 Finish Breakpoints

A finish breakpoint is a temporary breakpoint set at the return address of a frame, based on the `finish` command. `gdb.FinishBreakpoint` extends `gdb.Breakpoint`. The underlying breakpoint will be disabled and deleted when the execution will run out of the breakpoint scope (i.e. `Breakpoint.stop` or `FinishBreakpoint.out_of_scope` triggered). Finish breakpoints are thread specific and must be create with the right thread selected.

Function: FinishBreakpoint.__init__ ([frame] [, internal])

  Create a finish breakpoint at the return address of the `gdb.Frame` object frame. If frame is not provided, this defaults to the newest frame. The optional internal argument allows the breakpoint to become invisible to the user. See Breakpoints In Python, for further details about this argument.

Function: FinishBreakpoint.out_of_scope (self)

  In some circumstances (e.g. `longjmp`, C`++` exceptions, GDB `return` command, …), a function may not properly terminate, and thus never hit the finish breakpoint. When GDB notices such a situation, the `out_of_scope` callback will be triggered.

  You may want to sub-class `gdb.FinishBreakpoint` and override this method:

      class MyFinishBreakpoint (gdb.FinishBreakpoint)
          def stop (self):
              print ("normal finish")
              return True

          def out_of_scope ():
              print ("abnormal finish")

Variable: FinishBreakpoint.return_value

  When GDB is stopped at a finish breakpoint and the frame used to build the `gdb.FinishBreakpoint` object had debug symbols, this attribute will contain a `gdb.Value` object corresponding to the return value of the function. The value will be `None` if the function return type is `void` or if the return value was not computable. This attribute is not writable.

Next: Lazy Strings In Python, Previous: Breakpoints In Python, Up: Python API [Contents][Index]