> If you build your C code as C++, exceptions will flow through it just fine.

Exceptions will propagate up the stack, but won't clean up resources since the C code expects to do that manually. Same is true for non-RAII C++ code that is not written to expect exceptions.

Your main point is correct though: Large parts of the C++ stdlib do not throw.

What? Everything in the STL works fine without exceptions. Only wrinkle is if one wants to handle out of memory in way besides crashing, although there is generally nothing better to do. Besides, the kernel will often kill processes rather than return malloc failures (see the OOM killer) anyway.