Thanks for the tip Erik, perldebguts has some clues as to what is happening.

I have made some progress in that when the debugger is in a normal module, variables _<$filename contain what the documentation says to expect.

When I'm inside one of my coderefs, I get the string __ANON__ or something like eval 6 quoted as a module name. I tried stuffing an array called _<__ANON with my lines of code, but this made no difference. Also, I'm presuming these debug variables are package not lexical, as they appear to be lumped together in a typeglob. Evidence suggests that all these debug variables go into package main::.

I want a way of priming the debugger with my lines of code before it drops into the coderef.

Update: Looking at perl5db.pl and perlfunc on caller, I see that what I need to do is fake a call, supplying the correct source and line information so that caller can see it. How to do this? I've re-read the chapters on XS programming in Advanced Perl programming , but this does not even mention the supplementary information passed into a call for the debugger. Maybe this book pre-dates perl5db. Any help would be appreciated.

--rW