.net C++/CLI:#pragma托管/非托管范围

我有一个混合模式DLL和一个包含托管和非托管代码的.cpp文件。简化的复制示例如下所示：

#include "stdafx.h"
#pragma managed // Just for explicitness (doesn't influence results)
#include <msclr\marshal.h>

void Test()
{
    System::String^ sName = "";
    msclr::interop::marshal_context context;
    context.marshal_as<const TCHAR*>(sName);
}

//#pragma unmanaged // uncomment this line to get errors

我发现可以通过在.cpp文件末尾添加

#pragma managed

来消除错误。但我仍然不明白为什么会出现错误。对我来说，

#pragma unmanaged

的这种行为似乎完全违反直觉。有人能解释一下吗

据我所知：

• #pragma（un）managed

  影响下面的代码编译。因此，如果它是在.cpp文件末尾定义的（下面没有任何内容），则它不应该有任何效果
• 还说：
  实例化模板函数时，定义模板时的pragma状态将确定它是托管函数还是非托管函数

marshal_context

模板在包含的文件

marshal.h

中定义，并且应该编译为托管（因为它在前一行有明确的#pragma），而不管文件底部的#pragma是什么

---

我在什么地方错了吗？

嗯，这是出乎意料的。显然，编译器的缺陷可能与模板的延迟扩展有关。只需保持愉快，并将#pragma managed放在源文件的底部即可。@HansPassant谢谢，我将保持这种方式。我怀疑我错过了什么。

2>  Test.cpp
2>C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\msclr\marshal.h(48): error C3280: 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler' : a member-function of a managed type cannot be compiled as an unmanaged function
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>          This diagnostic occurred in the compiler generated function 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler(void)'
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\msclr\marshal.h(48): error C3642: 'System::Object::Object(void)' : cannot call a function with __clrcall calling convention from native code
2>          This diagnostic occurred in the compiler generated function 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler(void)'
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\msclr\marshal.h(48): error C3175: 'System::Object::Object' : cannot call a method of a managed type from unmanaged function 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler'
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>          This diagnostic occurred in the compiler generated function 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler(void)'
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\msclr\marshal.h(48): error C3821: 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler(void)': managed type or function cannot be used in an unmanaged function
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>          This diagnostic occurred in the compiler generated function 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler(void)'
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\msclr\marshal.h(282): error C3645: 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler' : __clrcall cannot be used on functions compiled to native code
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]
2>          This diagnostic occurred in the compiler generated function 'msclr::interop::marshal_context::internal_marshaler<_To_Type,_From_Type,_Needs_Context>::internal_marshaler(void)'
2>          with
2>          [
2>              _To_Type=const wchar_t *,
2>              _From_Type=System::String ^,
2>              _Needs_Context=true
2>          ]