Cannot define a custom DEBUGGER

Question

No matter what I do, I can't define a stable custom exception handler.  I've put up with the GUI-based one which I have always disliked because it is fiddly, unstable, and can't be copy-pasted easily, but I've had enough and just want a standard terminal output.

As a simple test I want to just capture the error code.  At first I wanted to output to console but I've whittled it down to just that.

`0 @` works, but calling any external function leads to the handler being called in an infinite loop.

I've tried to get this to work on my 32-bit copy and the latest 64-bit release.

protectedexterns

variable err

 

: my-debugger  ( errcode *context -- filter )

    drop                      \ ignore context pointer for now

    \ task0-io op-handle !

 

    err !

    \ ." Exception code: "

    \ ." (terminal handler — no GUI popup)" cr

    false

;

 

' my-debugger to-callback DEBUGGER

: test 255 0 ['] getcurrentdirectory catch  err ? ;

Answer 1

An update:  I tried it with a function from a different library that's STDCALL and it catches exceptions without an endless loop there.  So it seems that the issue is with WINAPI somehow.

Another update:  Claude AI explained it to me and got me a working exception handler.  Didn't realize that it was this low-level!

Answer 2

Our version for Linux64 attempts to give you as much info as possible e.g.

Arithmetic error (e.g. divide by zero), probably in DIVZERO, called from:
THROWTESTZ THROWTEST (INTERPRET) DEFER CATCH

Answer 3

We recently extended ours to include tracing of exceptions in external library functions e.g.

Illegal memory access, probably in external library: /lib/x86_64-linux-gnu/libc.so.6, called from:
STRLEN THROWTESTL THROWTEST (INTERPRET) DEFER