Question

I’ve accidentally removed Win2K compatibility from an application by using GetProcessID.

I use it like this, to get the main HWND for the launched application.

ShellExecuteEx(&info); // Launch application HANDLE han = info.hProcess; // Get process  cbinfo.han = han;  //Call EnumWindows to enumerate windows.... //with this as the callback  static BOOL CALLBACK enumproc(HWND hwnd, LPARAM lParam) {   DWORD id;   GetWIndowThreadProcessID(hwnd, &id);   if (id == GetProcessID(cbinfo.han))     setResult(hwnd)  ... } 

Any ideas how the same function could be acheived on Win2K?

Answer 1

There is an ‘sort-of-unsupported’ function: ZwQueryInformationProcess(): see

http://msdn.microsoft.com/en-us/library/ms687420.aspx

This will give you the process id (amongst other things), given the handle. This isn’t guaranteed to work with future Windows versions, so I’d suggest having a helper function that tests the OS version and then uses GetProcAddress() to call either GetProcessId() for XP and above, and ZwQueryInformationProcess() for Win2K only.