So if I want to pass a list to my callback function through WinApi I use GCHandle // object to IntPtr (before calling WinApi): List<string> list1 = new List<string>(); GCHandle handle1 = GCHandle.Alloc(list1); IntPtr parameter = (IntPtr) handle1; // call WinAPi and pass the parameter here // then free the handle when not needed: handle1.Free(); … Read more
intptr_t is a new invention, created after 64-bit and even 128-bit memory addresses were imagined. If you ever need to cast a pointer into an integer type, always use intptr_t. Doing anything else will cause unnecessary problems for people who need to port your code in the future. It took a long time to iron … Read more
Is it a good idea to use intptr_t as a general-purpose storage (to hold pointers and integer values) instead of void*? No. intptr_t is not guaranteed to exist. First, as you note, it was introduced in C99. Second, implementations are not required to have an integer type big enough to hold converted pointer values without … Read more
It’s a “native (platform-specific) size integer.” It’s internally represented as void* but exposed as an integer. You can use it whenever you need to store an unmanaged pointer and don’t want to use unsafe code. IntPtr.Zero is effectively NULL (a null pointer).