libquickmail
C library for sending e-mail (with attachments) from C/C++
C library intended to give C/C++ developers a quick and easy way to send e-mail from their applications. Supports multiple To/Cc/Bcc recipients and multiple attachments without size limitation. For the actual SMTP communication either libcurl can be used or the built in SMTP support. The library can also be used to just create a multipart MIME message body.
Also comes with a command line application (quickmail) for sending mails (mutiple attachments supported) from command line or scripts...