error 2059 in loadlibrary

I'm attempting to run a code through matlab on Windows 10 which was previously run on windows XP. Currently running MATLAB 2015a (64-bit) with Windows 7.1 SDK as the compiler. I get the following error:

Error using loadlibrary (line 395)
Building quadrupledll_thunk_pcwin64 failed.
quadrupledll.h(14) : error C2059: syntax error : 'string'
quadrupledll.h(16) : error C2059: syntax error : 'string'
quadrupledll.h(18) : error C2059: syntax error : 'string'
I assume referring to the lines beginning 'extern'.

The header file is as follows:

// The following ifdef block is the standard way of creating macros which make exporting 
// from a DLL simpler. All files within this DLL are compiled with the QUADRUPLEDLL_EXPORTS
// symbol defined on the command line. this symbol should not be defined on any project
// that uses this DLL. This way any other project whose source files include this file see 
// QUADRUPLEDLL_API functions as being imported from a DLL, wheras this DLL sees symbols
// defined with this macro as being exported.

#ifdef QUADRUPLEDLL_EXPORTS
#define QUADRUPLEDLL_API __declspec(dllexport)
#else
#define QUADRUPLEDLL_API __declspec(dllimport)
#endif

extern "C" QUADRUPLEDLL_API int  __stdcall move_left_assembly(int,int);

extern "C" QUADRUPLEDLL_API int  __stdcall move_right_assembly(int,int);

extern "C" QUADRUPLEDLL_API int  __stdcall cleanup();

[Walter Roberson]

That is the sort of error I would expect if that code were being compiled with a C compiler instead of a C++ compiler.

[Guillaume]

In any case, it would be useful to see what's on lines 15, 17 and 19

[Walter Roberson]

The line numbers match up to the extern "C" messages. Lines 15, 17, 19 are probably blank as shown.

Conor, what is the compilation command being used?

[Walter Roberson]

Jack C:

We are volunteers. The "price" we charge for answering questions is that your questions and remarks and the answers to them stay public, in order for everyone to be able to learn from them. When you delete your content, we start to feel as if you are treating us as if we are free private consultants, and we are not happy about that.

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Philip Borghesani]

Loadlibrary compiles all thunk files as c not c++. The header file used must be c compatible, wrap all extern "C" statements with #ifdef __cplusplus as is normally recommended for c compatible headers.

[Walter Roberson]

 #ifdef... 
extern "C" {
#endif
Put the declaration here 
#ifdef... 
}
#endif

As an outline