This function is the default dialog procedure for the file dialog.

#define INCL_winstdfile
#include <os2.h>

HWND       hwnd;       /*  Dialog-window handle. */
ULONG      msg;        /*  Message identity. */
MPARAM     mp1;        /*  Parameter 1. */
MPARAM     mp2;        /*  Parameter 2. */
MRESULT    mresReply;  /*  Message-return data. */

mresReply = WinDefFileDlgProc(hwnd, msg, mp1,
              mp2);