The following question, using quantlib function in my c++ program, asks about the usage of a popular quantitative finance library, QuantLib, but the question itself does not relate to quantitative finance. Would such a question belong here or on Stack Overflow?
Five close votes is all you need. So if enough people agree with you, then the discussion would already be over.
I doubt it's off-topic for the same reason that @vonjd states:
It is about a specific problem with a specific quant lib.
Also, truely off-topic questions don't get any responses at all. The fact that two people would take the time to write any sort of answer means the question can't be that offensive.
This question is not in scope. Although our community may contain knowledgeable individuals with the necessary familiarity and experience to answer this question, those community members are very likely also active Stack Overflow users. Furthermore, answering the question itself may not require specific knowledge of this library and definitely does not require specific knowledge of quantitative finance.
Thus far, the two answers posted have absolutely no quantitative finance content to them. They are purely programming-related advice. @DirkEddelbuettel even writes
This is really no different than linking to any other external library.
while @DmitriNesturuk writes
This is off-topic and maybe belongs to StackOverflow, but here goes.
If even the two answers admit that this is not a quant question but a programming question, we should close this as off-topic (or migrate).