> Any established C codebase, for example the kernel or Postgres?

Obviously you mean the Linux kernel, specifically. Also C++ has gotten a lot better since 2003 and before.

Examples of C++ usage in commercial codebases:

- anything Nintendo has written since 2010 (including microkernel, entire OS and all, for 3DS and Switch 1/2)

- well-known, high performing databases like ScyllaDB

> you just have to be careful about allocations as C++ makes it way easier to accidentally allocate than C does.

With the exception of exceptions (and coroutines but that's easily customizable), it's merely a standard library thing and doesn't affect language features (incl. language features exposed as std:: funcs/traits)

C++ has got a bad rep because it never fixes broken stdlib parts due to API and ABI concerns, and has many footguns due to this, that might make Rust and C better choices in corporate environments. However, IMHO, C++ is a much better language than C for personal projects, or when having a team of experienced folks.

> Any established C codebase

Anecdotally, GCC and GDB successfully (and incrementally) switched to C++ form C in the recent past.

The Linux kernel will never do it for ideological reasons of course.

I don't know about Postgres.

Nothing is stopping you from linking C++ code to Postgres.

But if you want to _contribute_ to PostgreSQL, it has to be in C.

I'm not sure about other compilers, but compiling C code as C++ with MSVC ends up with pretty much the exact same code, instruction by instruction. C++ is a bit more strict though especially with casting, so a lot of code won't compile out of the box.

C++ code compiles to a different function names in object file (name mangling). You probably need to put a lot of ugly `#ifdef __cplusplus extern "C" {` boilerplate in your headers, otherwise C and C++ files will not compile together.

Don't forget the infamous pattern used in some C projects too:

  struct foo decl = {
    .member = /* ... */
    .next = &(struct nested_pointer) {
        .nested_member = /* ... */,
    },
    .array = (struct nested_array[]) {
      [0] = { /* ... */ },
    }
  };

This pattern does not work in C++ as the nested declarations become temporaries.