Open Source VoIP/SIP Windows C API

It seems there is something for apple, Open Source VoIP/SIP Objective-C Code

Is there a similar stack for WIndows that anyone HAS EXPERIENCE with and is easy to implement?

I have followed most of the leads here http://www.voip-info.org/wiki/view/Open+Source+VOIP+Software .

But they开发者_运维问答 are abandoned or not a Standard windows C API.

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I found this a while back and it looks really promising:

http://www.pjsip.org/