[Doxygen-develop] [PATCH] warn about maintaining line numbers with INPUT_FILTER

[Anthony F. <ant...@gm...>]

Greetings.

I recently spent far longer than I should have, trying to track down
why my code anchors were offset.

It turns out that I had been using:

   INPUT_FILTER = "grep -v 'something to ignore'"

But this removed the lines entirely; that meant that the code scanner
"saw" different line numbers than the cpp-to-html generator.  Once I
realized what was happening, I got the same result by using:

   INPUT_FILTER = "sed -e 's/.*something to ignore.*//'"

But I might have saved myself a few hours if I had seen a warning about it.  :)

Since I was already doing the other patch, here's one to add a bit of
warning text about this possibility.

Thanks once again for the excellent tool!

Best regards,
Anthony Foiani