FC just posted the following advice. I think these kind of tricks should be gathered up into a perldoc which we can use. I know I could have saved some time if I knew these tricks. (I know other tricks which I could add.) If people like the idea how about perlgdbtricks.pod or something like that? From FC: This should give you the file and line number: (gdb) p Perl_warn(my_perl, "") Also, it may help you to reduce the test case if you get a Perl backtrace: (gdb) p Perl_eval_pv(my_perl,"use Carp; Carp::cluck 'foo'",0) -- perl -Mre=debug -e "/just|another|perl|hacker/"Thread Next