Regardless of what you consider a GC (let's not have that debate for the millionth time on the internet...), for the point I was trying to make, I was not including RC as a form of GC. And I don't think Fil-C relies solely on RC either.
Which only appears relevant if you disregard critical differences like this:
The GCC garbage collector GGC is only invoked explicitly. In contrast with many other garbage collectors, it is not implicitly invoked by allocation routines when a lot of memory has been consumed. [1]
There are many C++ programmers and we are not the same!
My original foray into GCs was making real time ones, and the Fil-C GC is based on that work. I haven’t fully made it real time friendly (the few locks it has aren’t RT-friendly) but if I had more time I could make it give you hard guarantees.
It’s already full concurrent and on the fly, so it won’t pause you
Those using Managed C++, C++/CLI, Unreal C++, the group of WG21 folks that voted C++11 GC into the standard, or targeting WebAssembly (which runs on a managed runtime for all practical purposes).
Windows developers using COM, and WinRT, Apple developers using IO and Driver Kit.
And of course it's easy to think of lots of apps that heavily use those or another form of GC.