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Some vendors base their compilers on GCC or Clang. But if you're not using their provided compilers, you either need to 1) be willing to shoulder the expense o

Some vendors base their compilers on GCC or Clang. But if you're not using their provided compilers, you either need to 1) be willing to shoulder the expense of making changes to GCC or Clang for whatever you're adding to the silicon in terms of instructions, and 2) be willing to get your combination of RTOS and compiler re-validated for the safety or operational standard on which you need to deliver. But even if you do use GCC or Clang, it doesn't change the mechanics of C++ as a poor language for embedded or operating system work. It just means you have the same choices (e.g. limited support for containers and strings, no exceptions, limited smart pointers, etc.) and you're making that choice based on GCC or Clang's limits.

moloch-hai 4y ago
Maybe you should explain to Andreas how C++ was such a bad choice for SerenityOS. Or to authors of the various RTOSes coded in it.
- phoehne 4y ago
  It's not impossible. Other people have done it. Some have done it with a minimal kernel or micro-kernel in C and then services on top of that in C++. Just doing a quick perusal of their code base, the low level stuff is functions and structs. So, yes, it is a .cpp but not that different from the code you'd write if it were a .c. And it appears they're turning off exceptions and the standard library (which is completely reasonable). They probably have some additional coding standard (internally) like you can't use anything with a constructor in certain contexts, etc. And on a validated RTOS - it might be in C++ under the covers. The examples that come to my mind aren't. But the world is a big and magical place, so I can't say for certain on every RTOS. The F35 uses C++ and a set of very restrictive internal coding standards built on https://en.wikipedia.org/wiki/MISRA_C https://en.wikipedia.org/wiki/MISRA_C. And no one will die if their copy of Serenity OS crashes.
  - pjmlp 4y ago
    If it is compiled by a C++ compiler, it is C++ regardless of the language features being used. Regarding language guides, C doesn't stop being C, even when castrated via MISRA-C.

moloch-hai 4y ago

Maybe you should explain to Andreas how C++ was such a bad choice for SerenityOS. Or to authors of the various RTOSes coded in it.

phoehne 4y ago
It's not impossible. Other people have done it. Some have done it with a minimal kernel or micro-kernel in C and then services on top of that in C++. Just doing a quick perusal of their code base, the low level stuff is functions and structs. So, yes, it is a .cpp but not that different from the code you'd write if it were a .c. And it appears they're turning off exceptions and the standard library (which is completely reasonable). They probably have some additional coding standard (internally) like you can't use anything with a constructor in certain contexts, etc. And on a validated RTOS - it might be in C++ under the covers. The examples that come to my mind aren't. But the world is a big and magical place, so I can't say for certain on every RTOS. The F35 uses C++ and a set of very restrictive internal coding standards built on https://en.wikipedia.org/wiki/MISRA_C https://en.wikipedia.org/wiki/MISRA_C. And no one will die if their copy of Serenity OS crashes.
- pjmlp 4y ago
  If it is compiled by a C++ compiler, it is C++ regardless of the language features being used. Regarding language guides, C doesn't stop being C, even when castrated via MISRA-C.