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marshal_context::marshal_as

Performs the marshaling on a specific data object to convert it between a managed and a native data type.

To_Type marshal_as<To_Type>(
   From_Type input 
);

[in] input

The value that you want to marshal to a To_Type variable.

A variable of type To_Type that is the converted value of input.

This function performs the marshaling on a specific data object. Use this function only with the conversions indicated by the table in Overview of Marshaling in C++.

If you try to marshal a pair of data types that are not supported, marshal_as will generate an error C4996 at compile time. Read the message supplied with this error for more information. The C4996 error can be generated for more than just deprecated functions. Two conditions that will generate this error are trying to marshal a pair of data types that are not supported and trying to use marshal_as for a conversion that requires a context.

The marshaling library consists of several header files. Any conversion requires only one file, but you can include additional files if you need to for other conversions. The table in Marshaling Overview in C++ indicates which marshaling file should be included for each conversion.

This example creates a context for marshaling from a System::String to a const char * variable type. The converted data will not be valid after the line that deletes the context.

// marshal_context_test.cpp
// compile with: /clr
#include <stdlib.h>
#include <string.h>
#include <msclr\marshal.h>

using namespace System;
using namespace msclr::interop;

int main() {
   marshal_context^ context = gcnew marshal_context();
   String^ message = gcnew String("Test String to Marshal");
   const char* result;
   result = context->marshal_as<const char*>( message );
   delete context;
   return 0;
}

Header file: <msclr\marshal.h>, <msclr\marshal_windows.h>, <msclr\marshal_cppstd.h>, or <msclr\marshal_atl.h>

Namespace: msclr::interop

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