I cannot find any solution in the web that works for my case. I read in Microsoft Developer Network, problems from here and several wikis, but nothing, but after reading so many info and some of the in contradiction to others ... I have a mess!
My history:
1- I have to change a software already created in Visual C++ (a DLL) and I do not know which Visual Studio was used to compile it, this DLL was working with a Visual Basic program.
2- I success in changing the program to use another communication protocol (that was the change... easy) and I have used Visual Studio 2012, I had some .NET issues in my computer, but I correct them and my computer should be fine, well I debug the dll and was working perfectly in my computer, but whenever I take the DLL to another makes a Run time error 53 (does not find the file), what actually does not find is the MSVCP110D.dll library, I guess because is a VS 2012 library (compiler vc11.0 so looks like is because of it), so I decide the next step:
3- I decide to migrate it to Mingw, because I heard is possible to create dll compatible with VB exe, ok I install eclipse and mingw, and modify again my C++ code to adapt to Mingw compiler and libraries, now I create the dll, also the .def and library .lib (well I rename the extension to .a) first gave me an error that can not find the function name, then I put:
#ifdef __cplusplus
extern "C" {
#endif
and the __stdcall (because the __cdecl is not for msvc, what I read), after this change the run time error change to 48 (I read this is a problem loading the DLL), I check is could be problem of the .def and try to create a new DLL with this .def usin the lib.exe and DUMPBIN from the VS 2012 compiler (but it does not work properly).
I comment all inside of my functions to just return the value 0, I remove the DllMain that there was (which is used for any program to find a entry point to initialise) but I commented because I do not initialise nothing, here I paste a bit of my code.
.h:
#define DLL_TESTER VB // define whenever I use the dll with the VB.exe
#ifdef DLL_TESTER
#ifdef DLLTRY_EXPORTS
//after I use the option -DCPDLLEXPORT to define and set the value to __declspec(dllexport)
#define ADDCALL __declspec(dllexport)
#else
#define ADDCALL __declspec(dllimport)
#endif
#define DLLTRY __stdcall
//this is supposly the correct one for VB.exe calls but try the __cdecl neither
#else
//if is not with a VB.exe the tester would be a C application
#define EXTDLLCALL __cdecl
#ifdef DLLTRY_EXPORTS
#define ADDCALL __declspec(dllexport) EXTDLLCALL
#else
#define ADDCALL __declspec(dllimport) EXTDLLCALL
#endif
#endif
May the order is wrong, but I try lot of different orders and none working:
__declspec(dllexport) before the return value (int) with the __stdcall and __cdecl next to it or in the other side of the return value,
in front with __stdcall and cdecl ... every order (because I saw different orders and every worked) but same run time error 48.
#include <string>
#include <Windows.h>
#ifdef __cplusplus
extern "C" {
#endif
Because there is link problems if is just declare it as a C++, so should be C to be properly linked to VB.exe (different compilers)
I define then some enums and structures, I think is fine, but may I should also export the struct if in the function call there is this struct as an argument?, in the previous version was not...but I created a function without arguments and does not work neither.
enum ERROR_DLL{ SUCCESS_CP_OK = 0,SUCCESS_CP_CANCELLED = 1}
struct SDllIdentity{
LPCSTR szID;
LPCSTR szDeviceID;
}
This is why I include windows.h because in the VS2012 this was working I thought it was failing because I was not using LPCSTR that is a char * type, but even if I change it to char * does not work.
int __stdcall __declspec(dllexport) InitialiseTerminal(const SDllIdentity* pSDllIdentity, LPCSTR szAddress, int nPort);
//May the order is wrong, but as previously said I tried diferent combinations
int __stdcall __declspec(dllexport) DisconnectTerminal(const SDllIdentity* pSDllIdentity);
//ADDCALL int DLLTRY DisconnectTerminal(const SDllIdentity* pSDllIdentity);
#ifdef __cplusplus
}
#endif
.cpp:
#include "dlltry.h"
//then I define some variables and a class, but I don't want to be exported
__stdcall int InitialiseTerminal(const SDllIdentity* pSDllIdentity, LPCSTR szAddress, int nPort) { return 0;}
__stdcall int /*ADDCALL*/ DisconnectTerminal(const SDllIdentity* pSDllIdentity) { return 0; }
I did not include all the functions, but all looks the same, I hope I am not forgeting a ";" :S, I looked in all this sites:
http://www.transmissionzero.co.uk/computing/building-dlls-with-mingw/ http://msdn.microsoft.com/en-us/library/z4zxe9k8.aspx
I tried to midify .def, create libdlltrx.a, all that I read, my only next solution would be to install VS2008, because I think was compile with that one ... but not sure, please read that I make it work before but because of incompatibilities I can not run it in others and I do not want to install any other software in others PCs.
