That is to say, if I want to use a third-party library, and that library was written to use the GC, and I want to _not_ use the GC, can I use said library? Or does using it require that I enable the GC for my code as well?
As soon as you disable the GC in D, you end up with a really awkward to use language, no closures, no exceptions, no dynamic arrays, I think you can't even use the common string in D without the GC.
People arguing that D can be used without a GC are just trying to sell you on something.
There is a flag to allocate them with malloc, and use RC.
> no dynamic arrays, I think you can't even use the common string in D without the GC.
Totally not true. You can't concatenate arrays (string are just arrays of char) with `arr1 ~ arr2` and you can't `new` them, but you can do pretty much anything else.
> People arguing that D can be used without a GC are just trying to sell you on something.
Of course, but C++ people have an unnatural aversion to GC also the D GC only ever collects if you allocate from it. No allocations == no collections.
For the most part, GC is a productivity enhancer, you can roll your own allocators, use malloc, etc. if you need to. You can statically ensure that some or all of your code doesn't use the GC and as expected there is a productivity/code maintenance price you pay for doing so.
If anything, D should stop pretending that it doesn't have a GC and stop trying to appeal to people who don't want a GC, it's a losing battle. D should just accept the fact that it is a GC'd language and start making the argument for why it's a better GC'd language than Java or C# or the host of other GC'd languages.
The vast majority of C++ developers do not want a GC'd version of C++, but it's possible that Java developers could be interested in a C++-like language that has a GC and good C compatibility.
GC is just one of the styles.
Yes, if you use "new" you get a GC allocation. But nobody makes you use "new". If you use the array concatenation operator, it uses the GC. But there are many ways to concatenate an array that don't use it.
As for closures, they get allocated on the GC only if they escape the stack frame. This is detected, and if you want to be told about it, annotate the function with @nogc.
What is that flag? Do you have a link to the documentation? I do remember talk about adding a feature that would allow exceptions to be allocated in @nogc code, but that was never ultimately implemented and looks to be postponed (to the best of my knowledge).
D is free to use for any purpose, being Boost licensed. We don't even keep track of who downloads it. Not that such info would do any good anyway, as anyone can host the distributions for download.
So yes, you can secretly use D at work, and we won't be able to tell on you!
(Lots of D users use a mix of GC and explicit allocation. Each has their best use cases.)
May I ask what your concern is?
Hence, if you don't do GC allocations, or at least do not do them in your realtime loop, it will not pause.
D is not a GC language. It's a language with an optional GC. (It also does not have the code gen compromises that fully GC languages rely on, such as write gates.)