Re^2: How to print the backtrace in a "catch" block?

Well, this is what I'm getting:

runtime error at - line 6.
the transaction failed at - line 23
    main::main_sub() called at - line 27
[download]

What I'm hoping for:

runtime error at - line 6.
the transaction failed at - line 23
        main::sub3() called at - line 3
        main::sub1() called at - line 13
    main::main_sub() called at - line 27
[download]

Or perhaps in Ruby code:

def dying_sub
    raise RuntimeError, "reason here"
end

def main
    begin
        dying_sub()
    rescue RuntimeError => e
        STDERR.puts e.backtrace
    end
end

main()

# Output:
# test.rb:2:in `dying_sub'
# test.rb:7:in `main'
# test.rb:13
[download]

Comment on Re^2: How to print the backtrace in a "catch" block? Select or Download Code

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Re^3: How to print the backtrace in a "catch" block? by Corion (Patriarch) on Jan 16, 2012 at 16:18 UTC
You will need to replace the `die` in `sub2` and/or `sub3` with a call to `confess` to get at the stack trace. Maybe you can install a `$SIG{__DIE__}` handler that stashes away the stack trace for later retrieval. I think that Carp::Always does this, but I've never used it.	[reply] [d/l] [select]
Re^4: How to print the backtrace in a "catch" block? by Anonymous Monk on Jan 16, 2012 at 17:15 UTC
`$SIG{__DIE__} = sub { cluck shift; }` [download] did in fact do what I want (just need to make it look nicer). Thanks	[reply] [d/l]
Re^5: How to print the backtrace in a "catch" block? by tobyink (Canon) on Jan 16, 2012 at 17:25 UTC
This looks nicer. It's got a winking open-mouthed smiley and a bug-eyed tongue-sticking-out smiley. `$SIG{__DIE__} = sub { cluck shift ;-0 } or 8-P ;` [download]	[reply] [d/l]
Re^4: How to print the backtrace in a "catch" block? by Marshall (Canon) on Jan 16, 2012 at 17:20 UTC
I looked at some of my code... It is possible to install a localized $SIG handler. In my case a stack trace means next to nothing..I want to know the exact DB record the failure happened on..that means something! In this code, I just have a __WARN__ handler, but I would presume that __DIE__ would be possible also. Of course $x has to be in scope for the $SIG handler! Anyway, installing a __DIE__ handler in the sub() might be easier and even better than a stack trace - although that could be done in the handler also. In this code, I just want to know which of 1M DB records caused the Warning - its not fatal for this code, but it is something I have to find and fix later. Just an idea.... `sub x { my ($x) = @_; # $x is an array ref to a DB record local $SIG{__WARN__} = sub { my $msg = shift; print STDERR "*******\n"; print STDERR $msg; print STDERR "current DB record: id=", $x->[ID]; }; # some stuff that might cause a Warning.... # some operations on the record pointed to by $x # maybe "abc123" is not numeric, etc. return $result; }` [download]	[reply] [d/l]
Re^4: How to print the backtrace in a "catch" block? by Anonymous Monk on Jan 16, 2012 at 16:31 UTC
Thanks, I suppose I'll try the signal approach. (I'm obviously not dying on purpose, but Perl is dying for me.) Was looking at Carp::Always's source code earlier, and that's what it uses.	[reply]