ok, i understand, the extern is used only in case i work in C project , but when i work with cpp project i dont need?

Best Regards

>>the first 8 lines are ok, the rest, you can explain like a child of 8 years?
>
>Not sure, I'm very weak in English.
>It would be better to read about "decorated names" in MSDN.
>I can't also understand, is your project C (plot.c) or C++ (plot.cpp)? In first case you shouldn't use 'extert "C"', otherwise this code works without any problems:
>

>// plot.cpp : Defines the entry point for the DLL application.
>//
>
>#include "stdafx.h"
>
>BOOL APIENTRY DllMain( HANDLE hModule,
>                       DWORD  ul_reason_for_call,
>                       LPVOID lpReserved
>					 )
>{
>    return TRUE;
>}
>
>extern "C" __declspec(dllexport) LPSTR say_hello(LPSTR cText)
>{
>	return "Hola";
>}
>