How to: Load Unmanaged Resources into a Byte Array

This topic discusses several ways to load unmanaged resources into a Byte array.

Examples

If you know the size of your unmanaged resource, you can preallocate a CLR array and then load the resource into the array using a pointer to the array block of the CLR array.

// load_unmanaged_resources_into_Byte_array.cpp
// compile with: /clr
using namespace System;
void unmanaged_func( unsigned char * p ) {
   for ( int i = 0; i < 10; i++ )
      p[ i ] = i;
}

public ref class A {
public:
   void func() {
      array<Byte> ^b = gcnew array<Byte>(10);
      pin_ptr<Byte> p =  &b[ 0 ];
      Byte * np = p;
      unmanaged_func( np );   // pass pointer to the block of CLR array.
      for ( int i = 0; i < 10; i++ )
         Console::Write( b[ i ] );
      Console::WriteLine();
   }
};

int main() {
   A^ g = gcnew A;
   g->func();
}

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This sample shows how to copy data from an unmanaged memory block to a managed array.

// load_unmanaged_resources_into_Byte_array_2.cpp
// compile with: /clr
using namespace System;
using namespace System::Runtime::InteropServices;

#include <string.h>
int main() {
   char buf[] = "Native String";
   int len = strlen(buf);
   array<Byte> ^byteArray = gcnew array<Byte>(len + 2);

   // convert any native pointer to IntPtr by doing C-Style cast
   Marshal::Copy( (IntPtr)buf, byteArray, 0, len );
}

See also

Using C++ Interop (Implicit PInvoke)