Are NDIS drivers allowed to use C++?
The first question is easy: can NDIS drivers be written in C++? The answer: yes. In this case, NDIS doesn’t have any official stance on C++, so we just fall back on the WDK’s general rules. As of Windows Driver Kit 8, Microsoft officially supports using a subset of the C++ language in drivers. (“Subset? What subset?” There’s more precise information here.)
The inevitable follow-up question is more nuanced: should NDIS drivers be written in C++? The answer is: it depends. Here are some facts that will help you derive a more specific answer:
- The NDIS API is a C API. There is no NDIS API that magically gets better or worse when you’re coming from C++ versus C.
- The NDIS team has no future plans to make a feature that requires C++. We are well-aware that many of our developers are dedicated fans of C, and have strong opinions on C++. Don’t worry — C isn’t going anywhere.
- The NDIS team may, in the future, add minor conveniences that only light up in C++. For example, the WDK macro ARRAYSIZE is defined differently for a C++ driver, which gives it better abilities to detect misuse with pointers. NDIS.H may start adding macros that offer minor improvements for C++ code, just like WDM.H already has today.
- Several major IHVs build their production NDIS miniport drivers using C++.
- Several major IHVs build their production NDIS miniport drivers using C.
- Microsoft builds some drivers in C and some drivers in C++.
- Our NDIS sample drivers are all in C. (This is largely for historical reasons, as these drivers were created before C++ was officially supported. If we were creating a new sample today, we’d consider writing it in C++.)
In summary, then, either language works fine, and it all comes down to a matter of your preference.