I used to develop asp classic by putting the business logic in com+ components which can then be referenced and used by light weight vb script in the asp page.
I used vb6, but I believe you can make com+ dll in any language
https://www.codeproject.com/Articles/13601/COM-in-plain-C
Overall I would recommend this approach in any classic asp project, as it allows you to separate the business logic from the view and program in a modern way.
Com+ is legacy technology now, but then so is classic asp. Here are some guides
http://www.chestysoft.com/component-services.asp
https://msdn.microsoft.com/en-us/library/ms524620(v=vs.90).aspx