If you want to stop at a function mod::subname in a not-yet-loaded module, you can use the
b postpone mod::subname [condition] debugger command. It will delay the setting of the breakpoint until the module has been loaded. The filename:linenumber syntax is not available, as far as I know.

So  b postpone UsefulModule::do_stuff should work.

This is described in the book "Pro Perl Debugging" from Richard Foley and Andy Lester.

In reply to Re: Perl Debugger: setting a breakpoint in another file with 'b' by hexcoder
in thread Perl Debugger: setting a breakpoint in another file with 'b' by Dumu

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