DllImport或LoadLibrary可获得最佳性能 [英] DllImport or LoadLibrary for best performance

问题描述

我有外部.DLL文件，其中带有快速汇编代码。调用此.DLL文件中的函数以获得最佳性能的最佳方法是什么？

I have external .DLL file with fast assembler code inside. What is the best way to call functions in this .DLL file to get best performance?

推荐答案

您的DLL可能位于python或c ++，无论做什么，都执行以下操作。

Your DLL might be in python or c++, whatever , do the same as follow.

这是C ++中的DLL文件。

This is your DLL file in C++.

标题：

extern "C" __declspec(dllexport) int MultiplyByTen(int numberToMultiply);

源代码文件

#include "DynamicDLLToCall.h"

int MultiplyByTen(int numberToMultiply)
{
    int returnValue = numberToMultiply * 10;
    return returnValue;
} 

看看下面的C＃代码：

static class NativeMethods
{
    [DllImport("kernel32.dll")]
    public static extern IntPtr LoadLibrary(string dllToLoad);

    [DllImport("kernel32.dll")]
    public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName);

    [DllImport("kernel32.dll")]
    public static extern bool FreeLibrary(IntPtr hModule);
}

class Program
{
    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    private delegate int MultiplyByTen(int numberToMultiply);

    static void Main(string[] args)
    {
            IntPtr pDll = NativeMethods.LoadLibrary(@"PathToYourDll.DLL");
            //oh dear, error handling here
            //if (pDll == IntPtr.Zero)

            IntPtr pAddressOfFunctionToCall = NativeMethods.GetProcAddress(pDll, "MultiplyByTen");
            //oh dear, error handling here
            //if(pAddressOfFunctionToCall == IntPtr.Zero)

            MultiplyByTen multiplyByTen = (MultiplyByTen)Marshal.GetDelegateForFunctionPointer(
                                                                                    pAddressOfFunctionToCall,
                                                                                    typeof(MultiplyByTen));

            int theResult = multiplyByTen(10);

            bool result = NativeMethods.FreeLibrary(pDll);
            //remaining code here

            Console.WriteLine(theResult);
    }
} 

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