What is the most used and flexible SMTP Client library in C/C++? [closed]

Question

I'm looking to crowd-source this, as I'm having bit of difficulty finding an "industry standard" library for SMTP in C/C++.

I'm looking for the ability to send emails with different MIME formats and attachments. I'd rather not re-invent the wheel by writing a thinly veiled library. But I'd also like to be able to include it in my software without odd licensing issues.

I've read over this related article: What RFCs need to be considered in developing an SMTP client?, regarding the RFCs which are relevant, and I'm looking over the RFCs too.

Answer 1

My personal favourite is VMime, for C++ only, but the highly reputed libcurl also has SMTP support (as well as many other features).

VMime has a dual license; I think curl has a sort of MIT-style license.

Answer 2

libquickmail has all the features you need. It supports things like multiple alternative bodies and attachments.