的P / Invoke和C ++包装的性能差异 [英] Performance differences between P/Invoke and C++ Wrappers
问题描述
在学习的P / Invoke的过程中，我问这个问题之前的：
In the process of learning P/Invoke, I asked this previous question:
不过，我不明白了在托管C创建一个包装++在C＃中使用p / Invoke的影响。创建，使用P同一个DLL / Invoke的在C＃中肯定产生了一个简洁的界面，因为我可以在嵌入的资源使用的DllImport，而是将对于本机DLL，在那里我做了封送自己一个托管C ++包装，有更好的表现？
However, I don't quite understand the implications of using P/Invoke in C# over creating a wrapper in Managed C++. Creating the same DLL using P/Invoke in C# definately resulted in a cleaner interface since I could use DLLImport on an embedded resource, but would a Managed C++ wrapper for a native DLL, where I do the marshaling myself, have better performance?
推荐答案
C ++包装要快，看看这个的 MSDN页面：
C++ wrapper should be faster, have a look at this MSDN page:
C ++的Interop使用数据编组的最快的方法，而的P / Invoke采用最可靠的方法。这意味着，C ++的Interop（典型的对C时尚++）默认情况下提供最佳的性能，而程序员负责解决情况下，这种行为是不是安全或适当。
C++ Interop uses the fastest possible method of data marshaling, whereas P/Invoke uses the most robust method. This means that C++ Interop (in a fashion typical for C++) provides optimal performance by default, and the programmer is responsible for addressing cases where this behavior is not safe or appropriate.
所以基本上主要的原因是的P / Invoke并钉住，块传输，错误检查，而C ++的互操作只是推栈上的参数并调用该函数。
So basically the main reason is that P/Invoke does pinning, blitting, error checking, while C++ interop just pushes the parameters on the stack and calls the function.
另外要记住的一点是，C ++可以调用几个API在一个单一的通话时的P / Invoke按地址传递每一个参数被固定和取消固定在每次调用，复制
和复制回等。
Another point to remember is that C++ can call a several APIs in a single call while P/Invoke EVERY parameter passed by address gets pinned and unpinned on EVERY call, copied and copied back, etc.
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