The relation between gtags and gtags-parser

Hi,

I didn't find anything in the GNU Global website about the relation between gtags and gtags-parser. I know that gtags parses the source files generates the database files, and I also that gtags-parser is capable of listing the objects in a single source file. It is very logical to think that gtags invokes gtags-parser on each of the source files, parses its output and adds it to the database. However, from what I saw, gtags-parser can provide much more (or different) information than gtags collects in its databases. For example, it has some options that gtags does not provide, like "-d" and "-t".

Hence, I'm very interested to know - does gtags use gtags-parser or does it use its own independent parser?

Thanks,
Shlomy