I design instrumentation for telescopes, in which C code on an embedded processor peeks and pokes device registers on an nearby FPGA. This C code forms an interface between hardware and the network.

In this system, I write a given function in C and surround it with a macro wrapper. This wrapper generates a JSON-RPC equivalent of the C function using the Jansson JSON library [1], complete with argument typechecking and error management. My C code can call the function normally, and an embedded webserver [2] can export it across the network where it's used fairly transparently by a Python stack on a control PC.

All three of these "embedded software" elements (the embedded webserver, the JSON library, and the FPGA interface) are very well suited to C. I have recently dabbled in moving parts of it to C++, and have found a few surprising impedance mismatches. (As I mentioned above, C++ still lacks reflection.)

The macros, here, are not for "elegance" or any other abstract purpose. They have allowed a ~80% reduction in boilerplate and an equally impressive reduction in the bugs and hassles associated with this kind of low-density, high-sprawl code.

[1]: https://digip.org/jansson/

[2]: https://www.gnu.org/software/libmicrohttpd