This example uses WinIsPhysInputEnabled to determine if physical input is enabled; if it is not, then WinEnablePhysInput is called to enable it.

#define INCL_WININPUT    /* Window Input Functions  */
#include <os2.h>

if (!WinIsPhysInputEnabled(HWND_DESKTOP))
   /* Enable queuing of physical input */
   WinEnablePhysInput(HWND_DESKTOP, TRUE);