https://bugs.winehq.org/show_bug.cgi?id=36873
--- Comment #15 from Ryan S. Northrup northrup@yellowapple.us --- Both the requested log and the revised patch which generated it (reintroducing the static vars for the previous cursor position) are now attached. The "ptin:" line is the position the application's passing in, the "ptout[0]" line is the mouse position returned from GetCursorPos, and the "ptout[1]" line is the previous position (i.e. the values of last_x and last_y at the time of function call).
So, from a sample:
168045.639:0035:0073:trace:win:GetMouseMovePointsEx (24 0x4e43f298 0x4e43f2b0 64 1) semi-stub 168045.639:0035:0073:trace:win:GetMouseMovePointsEx ptin: 466 775 168045.639:0035:0073:trace:win:GetMouseMovePointsEx ptout[0]: 466 775 168045.639:0035:0073:trace:win:GetMouseMovePointsEx ptout[1]: 479 787
We can see that "ptin" and "ptout[0]" are identical, even though the former came from the function args and the latter came from GetCursorPos.