check $lineno valid

[DmitryYudin]

I faced with the following error when processing linux sources as described in a ReadMe doc:

While processing /tmp/tmp.qAxBB9H4WR: Use of uninitialized value in pattern match (m//) at /mnt/work/opensource/elixir/find-file-doc-comments.pl
 line 134.

Please, find tmp.qAxBB9H4WR attached.
tmp.qAxBB9H4WR.txt

[cxw42]

Hmm... we might need to skip running find-file-doc-comments.pl on asm files. May also relate to #232 .

[DmitryYudin]

in addition to above:
ctags: Notice: ignoring null tag in /tmp/tmp.t2JX2ITiGb/misc_64.S(line: 644, language: LdScript)

[cxw42]

I don't know about the ctags notice. However, I would like to propose a different solution, given at https://github.com/bootlin/elixir/compare/master...cxw42:elixir:issue232-cwhite?expand=1 . The loops that test while $lineno are incorrect since $lineno is truthy even when negative. I think we should add a check earlier in the function to make sure that doesn't happen.

@DmitryYudin would you be willing to test https://github.com/cxw42/elixir/tree/issue232-cwhite and see if it works for you? I ran it against your testcase and mine and got no warnings (and no other output) on both files.

Thanks for considering this alternative!

[cxw42]

(And, I should have said some weeks ago --- Thanks @DmitryYudin for being willing to work on this!)