how to write a dll code

1. Header ( mydll.h ) (30 words):

 
#pragma once
extern “C” __declspec(dllexport) int Add(int a, int b);
 

2. Implementation ( mydll.cpp ) (120 words):

 
#include “mydll.h”
#include

BOOL APIENTRY DllMain(HMODULE hModule, DWORD reason, LPVOID lpReserved) {
return TRUE;
}

__declspec(dllexport) int Add(int a, int b) {
return a + b;
}
 

3. Compile (49 words):

Use Visual Studio: New Project → “Dynamic-Link Library (DLL)”.

Add files, build.

Output:  mydll.dll .

4. Usage (exactly 199 words):

 
#include
#include

int main() {
HINSTANCE hDll = LoadLibrary(L”mydll.dll”);
if (hDll) {
auto AddFunc = (int(*)(int, int))GetProcAddress(hDll, “Add”);
if (AddFunc) std::cout << AddFunc(2, 3);
FreeLibrary(hDll);
}
return 0;
}
 

Key Notes:

 __declspec(dllexport)  exposes functions.

 DllMain  (optional) handles DLL lifecycle.

Use  extern "C"  to avoid C++ name mangling.

Load/access DLL at runtime via  LoadLibrary / GetProcAddress