This function creates a secondary window from a dialog template in a resource. The secondary window is modeless.

#define INCL_SW
#include <os2.h>

HWND       hwndParent;     /*  Parent window handle. */
HWND       hwndOwner;      /*  Owner window handle. */
PFNWP      pfnDlgProc;     /*  Secondary window procedure. */
HMODULE    hmod;           /*  Module handle. */
ULONG      idDlg;          /*  Resource ID of dialog template. */
PVOID      pCreateParams;  /*  Parameters passed to secondary window proc. */
HWND       hwnd;           /*  Window handle. */

hwnd = WinLoadSecondaryWindow(hwndParent,
         hwndOwner, pfnDlgProc, hmod, idDlg,
         pCreateParams);