How to free IntPtr in C #?

Question

How to free ptrSentFromPinvokedDLL?

IntPtr ptrSentFromPinvokedDLL= IntPtr.Zero; int resultFromVendor = CallVendorDll(ref ptrSentFromPinvokedDLL); resultFromVendor = DoMoreWorkFromVendorDLL( ptrSentFromPinvokedDLL, "workonthis"); // Free ptrSentFromPinvokedDLLhere 

Answer 1

Ideally, either the provider is worried about this, or there is a provider function to free up memory. If not, you need to know how the provider allocated the memory. For example, if a provider allocated memory using LocalAlloc in kernel32.dll , you can free memory using Marshal.FreeHGlobal(IntPtr) . Similarly, if the CoTaskMemAlloc memory CoTaskMemAlloc , then Marshal.FreeCoTaskMem(IntPtr) will be used to free memory. Therefore, check the documentation and act accordingly.

For reference, here

Answer 2

There is no way to find out how to free it, or even need to free it without seeing the code inside CallVendorDll . (Or some documentation)