Re^4: How can I print variable contents from the debugger non-interactively? (@DB::typeahead)

> yes, it's still unclear for me if you want to step thru or run an automatic trace.

I think stepping thru the code would imply an interactive session. I am looking for an automatic trace, it would be nice to indicate which lines/variables should be printed, but having something that prints all of the variables modified and statements run would suffice. (huge output, but that isn't a problem!) There are some autotrace modules that may work, but I would like to accomplish this without additional modules. (lets make believe we are air gapped and getting to cpan is a problem)

> At least in .perldb with afterinit
sub afterinit { push @DB::typeahead, "b 4", "b 6"; }

So this isn't exactly thru the $ENV{PERLDB_OPTS} environment variable but using a file .perldb is easy enough to do. (though, @DB::typeahead is not a supported interface and is subject to change in future releases.)

I attempted the following:
echo "sub afterinit { push @DB::typeahead, \"a 119 p \$var\"; }" > .perldb

I see:


 29: main();
auto(-1) DB<1> a 199 p __DB<2> (some program output)
and then it shows 6556 segmentation fault  with exit code 139.
[download]

not sure what is causing the seg fault and I again lose the automatic printing of all the statements, but I see some of the program output. Hopefully the above typeahead gives you an idea of what I'm trying to accomplish.

Thanks again for all the thought and replies.

http://dave.thehorners.com/tech-talk/programming/94-perl-programming

Comment on Re^4: How can I print variable contents from the debugger non-interactively? (@DB::typeahead) Download Code

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Re^5: How can I print variable contents from the debugger non-interactively? (@DB::typeahead) by LanX (Saint) on Jul 17, 2017 at 20:13 UTC
There is already a whole trace infrastructure apart from the debugger. Please note the debugger IS eventually for interaction. And I've shown you already 3 approaches, with varying details and footprint print when you break back to prompt { print whenever you pass a certain point with a or b print whenever you execute any statement with w > push @DB::typeahead, \"a 119 p \$var\"; Please note again that a , b and w only take real Perl code but p is a debugger command Commands accepting debugger commands are documented with `db_cmd` or `db_command` `DB<27> h { { db_command Define debugger command to run before each prompt. { ? List debugger commands to run before each prompt. {{ db_command Add to the list of debugger commands to run before ea +ch prompt. { * Delete the list of debugger commands to run before eac +h prompt.` [download] Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply] [d/l] [select]
Re^6: How can I print variable contents from the debugger non-interactively? (@DB::typeahead) by davehorner (Scribe) on Jul 17, 2017 at 20:26 UTC
> I've shown you already 3 approaches, with varying details and footprint I very much appreciate your responses! > There is already a whole trace infrastructure apart from the debugger. the debugger IS eventually for interaction. I've seen Devel::Trace but that also seems to only print the statements and not the data. If there is a whole trace infrastructure (/w data printing capabilities) outside of the debugger I am not aware of it and would appreciate a pointer if so. http://dave.thehorners.com/tech-talk/programming/94-perl-programming	[reply]
Re^7: How can I print variable contents from the debugger non-interactively? (@DB::typeahead) by LanX (Saint) on Jul 17, 2017 at 20:37 UTC
Sorry I'm not really a user of debugger, tracer or profiler .... ... but you might want to have a look here http://search.cpan.org/search?query=trace&mode=all HTH! :) Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply]