C++ library to send mail via SMTP on HP-UNX

Hello Gurus,
I am a java guy. I am sorry if my below posting sounds basic stuffs and/or addressed earlier often times. Basically I am working for a project that involves C++ in the back-end and Java Swing in the front-end.

So currently developing a module that sends out an e-mail message (just plain text) to all recipients and/or group of recipients from Java Swing GUI that uses C++ back to send mail using HP-UNIX "sendmail" command via SMTP. After having spent quite a bit of time trying to figure out a way to get the delivery status back off of SMTP server (to display the status for each recipients in GUI), I have been unable to find a way to get the delivery status off of server. I just piping the message to server from C++ that has "sendmail" command along with address & message.

I was hoping to find out - Is there a library api available for C++ to send mail via SMTP to make life easier?

I would truly appreciate any input/suggestion on this.

Many thanks!

-RD