Giving C a superpower: custom header file (safe_c.h)

Intentionally or not, this post demonstrates one of the things that makes safer abstractions in C less desirable: the shared pointer implementation uses a POSIX mutex, which means it’s (1) not cross platform, and (2) pays the mutex overhead even in provably single-threaded contexts. In other words, it’s not a zero-cost abstraction.

C++’s shared pointer has the same problem; Rust avoids it by having two types (Rc and Arc) that the developer can select from (and which the compiler will prevent you from using unsafely).

The number of times I might want to write something in C and have it less likely to crash absolutely dwarfs the number of times I care about that code being cross-platform.

Sure, cross-platform is desirable, if there's no cost involved, and mandatory if you actually need it, but it's a "nice to have" most of the time, not a "needs this".

As for mutex overheads, yep, that's annoying, but really, how annoying ? Modern CPUs are fast. Very very fast. Personally I'm far more likely to use an os_unfair_lock_t than a pthread_mutex_t (see the previous point) which minimizes the locking to a memory barrier, but even if locking were slow, I think I'd prefer safe.

Rust is, I'm sure, great. It's not something I'm personally interested in getting involved with, but it's not necessary for C (or even this extra header) to do everything that Rust can do, for it to be an improvement on what is available.

There's simply too much out there written in C to say "just use Rust, or Swift, or ..." - too many libraries, too many resources, too many tutorials, etc. You pays your money and takes your choice.