[rdw]

You're right, and it's got more layers than that. C# does have value types, which are not boxed, and using them judiciously can avoid garbage. However, they are a more recent addition to the language (which started as a lame Java clone), and so the standard library tends to not know about them. Really trivial operations will allocate hundreds of bytes of garbage for no good reason. Example: iterating over a Dictionary. Or, IIRC, getting the current time. They've been cleaning up these functions to not create garbage over tiem, of course, but it's never fast enough for my taste and leads to some truly awful workarounds.

[wesnerm2]

C# had value types and pointers from the very beginning. These are not a recent addition. The standard library does know about them. However, not until C# 2.0, which introduced generics, were collections able to avoid boxing value types.

There are some cases where allocations are made when they could have been avoided. Iterating over a dictionary creates a single IEnumerator object. Async methods, tuples, delegates, and lambda expressions also allocate memory as do literal strings. It is possible to have struct-based iterators and disposers. There are some recently added mitigations such as a ValueTask, ValueTuple, function pointers, ref structs, conversions of literals to read-only spans, that eliminate allocations.

DateTime is a value type and doesn't allocate memory. Getting the current time does not allocate memory.

With the recent additions to ref types and Span<>, C# provides a lot of type-safe ways to avoid garbage collections. You can always use pointers if need be.

[ayende]

And to put that in context, 2.0 was around 2003, iirc

[int_19h]

It was 2005.

But even then, arrays of value types were available since C# 1.0 (2001).

[pjmlp]

Value types in .NET exist since forever, version 1.0.

Besides the runtime also does C++ since version 1.0, and any language can tap into it.