[omnicognate]

C# makes it possible to do C (not C++) like memory management but it does not make it easy. Unsafe C# code is really, really, really unsafe, much more unsafe than equivalent C code, and does not compose well. It's improving, with Span/Memory, etc, but it remains an absolute last resort.

[pjmlp]

C and C++ memory managements are alike, C# doesn't need reference counted library types.

If you mean RAII, they can be easily done with IDisposable, using and Rosylin analysers that throw errors when usings are forgotten.

And yes, manually memory management should be last resource, proven by profiler data.

[omnicognate]

I do mean RAII, which is fundamental to C++. Memory management without it is not "C++ like".

IDisposable is not a substitute for RAII, and C# has nothing that can manage ownership in equivalent ways as it lacks deterministic destruction. Implementing, for example, a data structure based on unmanaged memory in C# in such a way that it can be safely used by code outside the library without undermining the safety of the language (i.e. without introducing the possibility of programming errors outside the data structure implementation causing leaks or memory corruption) is an exercise in discipline and requires a thorough understanding of the runtime - eg. knowing that an object can be garbage collected while a method on it is executing. I know this because I've done it (as a last resort after extensive profiling and production use of various optimised, managed versions of the library).

[pjmlp]

Maybe you should explore better Marshall Interop services and the span related improvements.

IDisposable is definitely an alternative when coupled with Roslyn analysis or SonarQube.

As if doing it in C++ doesn't require the same knowledge level, worse actually, as it also requires ISO C++ mastery and a good knowledge of how each compiler being used handle IB and UB.

Also unless static analysis is getting used, RAII can also get thr ownership wrong, specially with use after move errors, or smart pointers incorrectly given as arguments.

[omnicognate]

I used Spans extensively. They help (mostly by providing efficient bounds checking), but not much. The main problem, as I mentioned initially, is the composability of this sort of code.

I wasn't trying to give some kind of defence of C++ here, just pointing out the dissimilarities to C#. This particular piece of code would have been far easier in C++ and RAII would have been a huge help, but the system as a whole would have been an utter nightmare in C++ (which I know because I've worked on multiple similar systems in C++).

[pjmlp]

Sure, but I am the opinion it does compose, if one embraces it isn't the same as writing C++ in C#, not trying to downplay your experience on the matter.

For example, here are the Roslyn analysers for a more RAII like experience with IDisposable,

https://github.com/DotNetAnalyzers/IDisposableAnalyzers

Turn "DISP004-Don't ignore created IDisposable." into a compiler error and you have your region allocated RAII like experience.

And moving a bit the goal posts, for those scenarios where C# fails completly to provide a usefull solution, we can rewrite just that module into C++ (preferably C++/CLI when only Windows matters), and have the best of both languages.

[legulere]

There's also ref which is almost like pointers and safe. Span/Memory do not remain an absolute last resort, they are becoming the standard way for string formatting/parsing/(de)serialization and IO.

[omnicognate]

I didn't say Span/Memory are a last resort, I said C style memory management (AllocHGlobal/Free), despite being somewhat improved by Span/Memory, remains an absolute last resort. Span/Memory aren't primarily aimed at handling unmanaged memory, though they're useful for it.

[pjmlp]

Of course C style memory management is a last resort, 99% of devs don't need it, and the 1% that actually need it, better learn to use V-Tune.

[tp600]

why is it more unsafe than equivalent C code? I always thought it's simply a way to enable C-like real pointers/native memory ...