Question

While working with WinAPI, I decided to implement a call to GetProcessAfinityMask in my C# application. However, I’ve seen two different signatures for this function.

One of them uses SafeProcessHandle for the handle:

[DllImport("kernel32.dll", CharSet=CharSet.Auto, SetLastError=true)]
public static extern bool GetProcessAffinityMask(SafeProcessHandle handle, out IntPtr processMask, out IntPtr systemMask);

The other possible version (on P/Invoke) uses IntPtr:

[DllImport("kernel32.dll",SetLastError = true)]
static extern bool GetProcessAffinityMask(IntPtr hProcess,
   out UIntPtr lpProcessAffinityMask, out UIntPtr lpSystemAffinityMask);

Given that both functions return the same values, what is the difference between passing a SafeProcessHandle instance or IntPtr?

Answer 1

Safe Handles and Critical Finalization MSDN Article is describing this difference.