Handling Unmanaged Memory Pointers in Managed Memory

__declspec(dllexport) typedef struct DataRecord
{
	int RecordBufferSize;
	int NumberOfFields;
	int NumberOfElements;
	int RecordType;
	UINT RecordInfoFlags;
	char* FieldDescription;
} DataRecord, *PDataRecord;

__declspec(dllexport) typedef struct DataVariable
{
	char InternalName[16];
	char Mnemonic[4];
	char CurveLabel[26];
	USHORT Format;
	union
	{
		USHORT NumberOfBytes;
		USHORT NumberOfElements;
	};
	USHORT UnitType;
	USHORT SpecialHandling;
	SHORT NumberOfDecimalPlaces;
	USHORT OffsetInRecord;
} DataVariable, *PDataVariable;