c#-7.2

I'm rewriting some of my extension methods using the new Span<T> type and I'm having trouble finding a way to properly pin a generic instance to be able to use parallel code to work on it. As an example, consider this extension method: public static unsafe void Fill<T>(this Span<T> span, [NotNull] Func<T> provider) where T : struct { int cores = Environment.ProcessorCount, batch = span.Length / cores, mod = span.Length % cores, sizeT = Unsafe.SizeOf<T>(); //fixed (void* p0 = &span.DangerousGetPinnableReference()) // This doesn't work, can't pin a T object void* p0 = Unsafe.AsPointer(ref span

C# 7.2 introduces two new types: Span<T> and Memory<T> that have better performance over earlier C# types like string[] . Question: What is the difference between Span<T> and Memory<T> ? Why would I use one over the other? Hussein Salman Span<T> is stack-only in nature while Memory<T> can exist on the heap. Span<T> is a new type we are adding to the platform to represent contiguous regions of arbitrary memory, with performance characteristics on par with T[]. Its APIs are similar to the array, but unlike arrays, it can point to either managed or native memory, or to memory allocated on the

Ive seen people using and discussing c# 7.2 features but I cant seem to find it. Ive got latest updates and only up to version 7.1 is listed. why and how can I get v7.2? specs: Visual studio 2017 version 15.4.4 Visual C# 2017 - 00369-60000-00001-AA303 Version 15.4.* of VS 2017 doesn't support C# 7.2. C# 7.2 support was introduced in VS 2017 version 15.5, which was released on December 4th . 来源： https://stackoverflow.com/questions/47328622/where-is-c-sharp-7-2-in-visual-studio-project-settings

How do I convert a string to a Span<T>? Span<char> mySpan = "My sample source string"; Span<T> and friends are included in .NET Core 2.1, so no additional NuGet-package needs to be installed. Dan Sorensen answer was correct at that date and based on the preview, but now it is outdated. For string the extension methods are AsSpan and AsMemory , that return ReadOnlySpan<char> and ReadOnlyMemory<char> respectively. Explicit AsReadOnlySpan is gone, because string s are immutable, so it makes no sense to get back a Span<char> (that is writeable). You need to install the System.Memory NuGet package

I notice that the following will compile and execute even though the local variables are not initialized. Is this a feature of Span? void Uninitialized() { Span<char> s1; var l1 = s1.Length; Span<char> s2; UninitializedOut(out s2); var l2 = s2.Length; } void UninitializedOut(out Span<char> s) {} This looks like an issue caused by reference assemblies, required because of the way that Span<T> has framework-specific internals. This means that in the reference assembly : there are no fields (edit: this isn't quite true - see footnote). A struct is considered assigned (for the purposes of

C# 7.2 introduced the in modifier for passing arguments by reference with the guarantee that the recipient will not modify the parameter. This article says: You should never use a non-readonly struct as the in parameters because it may negatively affect performance and could lead to an obscure behavior if the struct is mutable What does this mean for built-in primitives such as int , double ? I would like to use in to express intent in code, but not at the cost of performance losses to defensive copies. Questions Is it safe to pass primitive types via in arguments and not have defensive copies