How to Dynamically Load and Call Functions from DLLs in C ?

Dynamic Loading of Functions from DLLs

Loading functions dynamically from DLLs (Dynamic Link Libraries) in C allows you to access functionality defined in separate modules at runtime. Here's how to approach this problem:

1. Load the DLL:

<br>HINSTANCE hDLL = LoadLibrary("path/to/dll.dll");<br>

This step loads the DLL into memory and returns a handle to it.

2. Get the Function Pointer:

To access a function within the DLL, you need to obtain its address using GetProcAddress:

<br>typedef int (__stdcall *f_funci)(); // Define function pointer type<br>f_funci funci = (f_funci)GetProcAddress(hDLL, "funci");<br>

This example assumes your function is named "funci" and uses the __stdcall calling convention.

3. Calling the Function:

Once you have the function pointer, you can call the function like any other function:

<br>int result = funci();<br>

4. Exporting the Function from the DLL:

In the DLL, your function must be exported using __declspec(dllexport) to make it accessible to other modules:

<br>int __declspec(dllexport) __stdcall funci() {<br>   // Function definition<br>}<br>

Additional Tips:

• It's advisable to free the DLL handle using FreeLibrary() when it's no longer needed.
• Use a function pointer type that accurately matches the function's signature in the DLL.
• Ensure proper error handling to handle any issues with DLL loading or function resolution.

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