This function indicates that the redrawing of a window is complete, generally as part of the processing of a WM_PAINT message.

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

HPS     hps;  /*  Presentation-space handle. */
BOOL    rc;   /*  Success indicator. */

rc = WinEndPaint(hps);