This function begins the enumeration process for all of the immediate child windows of a specified window.

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

HWND     hwnd;        /*  Handle of the window whose child windows are to be enumerated. */
HENUM    henumHenum;  /*  Enumeration handle. */

henumHenum = WinBeginEnumWindows(hwnd);