This function shows or hides the cursor that is associated with a specified window.

#define INCL_WINCURSORS /* Or use INCL_WIN, INCL_PM, Also in COMMON section */
#include <os2.h>

HWND    hwnd;   /*  Handle of window to which the cursor belongs. */
BOOL    fShow;  /*  Show indicator. */
BOOL    rc;     /*  Success indicator. */

rc = WinShowCursor(hwnd, fShow);