Here's a common debugging scenario: I am investigating a failure and for whatever reason I cannot instrument the relevant code with edebug. I can, however, in most cases get a backtrace via
debug-on-entry. In the backtrace, I can jump to code along the call stack, but how does one get the values or arguments or variables? Here's an simple example:
(define-error 'test-signal "Test signal" 'error) (setq myvar 42) (defun foo (arg) (signal 'test-signal '(1 2 3))) (provide 'foo)
Now Imagine I have debug-on-error turned on, and do
Once I'm in the debugger, what commands do I need to issue to see that the value of
arg is 123 and of
myvar is 42?
debugger-eval-expression always seems to return "Symbol's value as variable is void".