Can I make direct calls to PostgreSQL server?

I am new to this list, forgive me if I do something wrong.

I am writing an application in C++ for Linux to post data to a PostgreSQL
server.
Can I make direct calls to PostgreSQL server? I have a lot of data to post to
the local PostgreSQL server. I am wondering if I can connect directly to it
to post data so I can by pass the extra layers of
command -> SQL text string -> port -> SQL interpreter -> internal DB command
I would like to go
command -> lib function call  -> internal DB command

All I can find is examples of how to make long text strings of SQL commands
then pass them to a local port then on into the server. Is this the only way?

--
Roy Souther <roy@silicontao.com>

01100010 10101110 11000110 11010110 00000100 10110010 10010110 11000110
01001110 11110110 11001110 00010110 10010110 00101110 10000100 10000100