ReadOnlySpan<T>.GetPinnableReference 方法

定義

命名空間:

System

組件:

System.Runtime.dll

來源:

ReadOnlySpan.cs

傳回 T 型別物件的唯讀參考，可用於釘選。

此方法的目的是要支援 .NET 編譯程式，而不是由使用者程式代碼呼叫。

public:
 T& ^ GetPinnableReference();

public ref readonly T GetPinnableReference ();

member this.GetPinnableReference : unit -> 'T

Public Function GetPinnableReference () As T

傳回

T

在索引 0 上範圍的項目參考，如果範圍是空的，則為 null。

範例

下列範例示範如何建立整數數位、將它釘選，以及將每個元素寫入主控台。

using System;

// Note: you must compile this sample using the unsafe flag.
// From the command line, type the following: csc sample.cs /unsafe

public class Example
{
    public static unsafe void Main()
    {
        int[] array = CreateInt32Array();

        // Create a span, pin it, and print its elements.
        Span<int> span = array.AsSpan();
        fixed (int* spanPtr = span)
        {
            Console.WriteLine($"Span contains {span.Length} elements:");
            for (int i = 0; i < span.Length; i++)
            {
                Console.WriteLine(spanPtr[i]);
            }
            Console.WriteLine();
        }

        // Create a read-only span, pin it, and print its elements.
        ReadOnlySpan<int> readonlyspan = array.AsSpan();
        fixed (int* readonlyspanPtr = readonlyspan)
        {
            Console.WriteLine($"ReadOnlySpan contains {readonlyspan.Length} elements:");
            for (int i = 0; i < readonlyspan.Length; i++)
            {
                Console.WriteLine(readonlyspanPtr[i]);
            }
            Console.WriteLine();
        }
    }

    private static int[] CreateInt32Array()
    {
        return new int[] { 100, 200, 300, 400, 500 };
    }
}

// The example displays the following output:
//       Span contains 5 elements:
//       100
//       200
//       300
//       400
//       500
//
//       ReadOnlySpan contains 5 elements:
//       100
//       200
//       300
//       400
//       500

#nowarn "9"
#nowarn "51"
open System
open FSharp.NativeInterop

let createInt32Array () =
    [| 100; 200; 300; 400; 500 |]

[<EntryPoint>]
let main _ =
    let array = createInt32Array()

    // Create a span, pin it, and print its elements.
    let span = array.AsSpan()
    let spanPtr = &&span.GetPinnableReference()
    printfn $"Span contains {span.Length} elements:"
    for i = 0 to span.Length - 1 do
        printfn $"{NativePtr.get spanPtr i}"
    printfn ""

    // Create a read-only span, pin it, and print its elements.
    let readonlyspan: ReadOnlySpan<int> = array.AsSpan()
    let readonlyspanPtr = &&readonlyspan.GetPinnableReference()
    
    printfn $"ReadOnlySpan contains {readonlyspan.Length} elements:"
    for i = 0 to readonlyspan.Length - 1 do
        printfn $"{NativePtr.get readonlyspanPtr i}"
    printfn ""
    0

// The example displays the following output:
//       Span contains 5 elements:
//       100
//       200
//       300
//       400
//       500
//
//       ReadOnlySpan contains 5 elements:
//       100
//       200
//       300
//       400
//       500

備註

應用程式不應該直接呼叫 GetPinnableReference。 相反地，呼叫端應該使用其語言的一般釘選語法，例如 C# 的 fixed 語句。

如果釘選 ReadOnlySpan<char>，則產生的 char* 不會假設為 null 終止。 此行為與釘選 string不同，其中產生的 char* 保證會以 Null 終止。