The CDM_GETFOLDERPATH message retrieves the path of the currently open folder or directory for an Explorer-style Open or Save As common dialog box. The dialog box must have been created with the OFN_EXPLORER flag; otherwise, the message fails.
CDM_GETFOLDERPATH wParam = (WPARAM) cbmax; lParam = (LPARAM) (LPTSTR) psz; // Corresponding macro int CommDlg_OpenSave_GetFolderPath(hdlg, psz, cbmax);
If the message succeeds, the return value is the size, in bytes or characters, of the path string, including the terminating NULL character. This is either the number of bytes or characters copied to the psz buffer, or the required buffer size if the buffer is too small.
If an error occurs, the return value is less than zero.