Multi-process transactions [share connections]

Hello !

I have complex system, which use PostgreSQL as a storage.
Web-interface use Apache+mod_perl, Pg.pm for connection.
I also have kernel of the system written in C++, which
works as a UNIX daemon and process request from frontend
mod_perl scripts. In some cases it needs to share transaction
along the forntend script [mod_perl process] and kernel
process [other process]. Is it possible?
If yes, what and how I must pass to kernel process?
Just connection_handler variable? Is perl[Pg.pm]::PQconnectdb return
value compatible with C[libpq]::PQsetdbLogin's function return value?
It is enough to pass only this variable to work with high-grade
transactions etc support in this case?

Thanks a lot for any helpful information.

--
best regards,
Ruslan A Dautkhanov rusland(at)scn(dot)ru