Re: Help with LoadLibrary and DLL


"omegayen " <omegayen@xxxxxxxxxxxxx> wrote in message news:hgmr02$pe7$1@xxxxxxxxxxxxxxxxxxxxx
Hi,

I am try to follow the example on http://guoliangye.com/2009/01/21/how-to-write-a-dll-in-cc-and-call-it-in-matlab/

I created two files

dll1.h

#ifndef MY_API
#define MY_API extern "C" __declspec(dllexport)
#endif
MY_API int add(int a, int b);
MY_API int sub(int a, int b);

dll1.cpp

#ifndef MY_API
#define MY_API extern "C" __declspec(dllexport)
#endif
#include "dll1.h"
int add(int a,int b)
{
return a + b;
}
int sub(int a,int b)
{
return a - b;
}

I think used Visual Studio 2008 SP1 Version 9 Pro on Windows Vista 64 bit using Matlab 2009b 64 bit to compile a x64 dll file.

I then use load library function such as loadlibrary('D:\dll1\Debug\dll1.dll', 'D:\dll1\dll1.h'); in MATLAB

when I do this i get the error message
??? Error using ==> loadlibrary at 422
Building SimpleDll_thunk_pcwin64 failed. Compiler output is:
SimpleDll_thunk_pcwin64.c
C:\Users\user_name_removed\Documents\Visual Studio 2008\Projects\SimpleDll\x64\Debug\SimpleDll.h(4) : error C2059: syntax error :
'string'
C:\Users\user_name_removed\Documents\Visual Studio 2008\Projects\SimpleDll\x64\Debug\SimpleDll.h(5) : error C2059: syntax error :
'string'

can anyone help tell me why I am getting error C2059 syntax error 'string' I suspect it has something to do with the extern "C"
__declspec(dllexport) line but am not sure how to change things up to work. thanks

Try changing dll1.h to:
#ifndef MY_API
#define MY_API
#endif
MY_API int add(int a, int b);
MY_API int sub(int a, int b);

The guard block around the #define statement in your cpp code is not needed but will not harm anything.

Phil


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