User32: SetCursorPos is declared (long, long), but Windows declares (int, int) #1745

User32.SetCursorPos takes two Java longs. Win32 declares both coordinates as int.

// contrib/platform/src/com/sun/jna/platform/win32/User32.java:2329
boolean SetCursorPos(long x, long y);

// um/WinUser.h (Windows SDK 10.0.28000)
WINUSERAPI
BOOL
WINAPI
SetCursorPos(
    _In_ int X,
    _In_ int Y);

What it can cause

On 64-bit Windows nothing goes wrong: each argument travels in a register, and SetCursorPos reads its low 32 bits. On 32-bit Windows the arguments go on the stack, and each long takes 8 bytes. SetCursorPos reads X from the low half of x and Y from the high half of x, which is 0 for any on-screen x, so the cursor lands at (x, 0). Because the function is stdcall, it also pops 8 bytes where 16 were pushed. I don't have 32-bit Windows to run this; it follows from the two declarations. User32Test.testSetCursorPos passes on 64-bit, which is consistent with it.

Fix

boolean SetCursorPos(int x, int y);. Changing the signature breaks callers compiled against the long version, so adding the int overload and deprecating the long one may be gentler. Happy to send a PR for whichever you prefer.

How this was found

By a research tool that compares each native declaration against the C declaration of the function it binds. Nothing was built or executed; every file quoted is in this repository at 5.19.1, and unchanged on master.