hwnd Identifies the parent window. This window receives any message boxes an application produces an error message box.[explanation correct?]
LpszOp Points to a null-terminated string specifying the operation to perform. This string can be "open" or "print". If its parameter is NULL, "open" is the default value.
LpszFile Points to a null-terminated string specifying the file to open.
LpszParams Points to a null-terminated string specifying parameters passed to the application when the lpszFile parameter specifies an executable file. If lpszFile points to a string specifying a document file, this parameter is NULL.
LpszDir Points to a null-terminated string specifying the default directory.
FsShowCmd Specifies whether the application window is to be shown when the application is opened. This parameter can be one of the following values:
1 SW_NORMAL Activates and displays a window. If the window is minimized or maximized, Windows restores it to its original size and position (same as SW_RESTORE ).
2 SW_SHOWMINIMIZED Activates a window and displays it as an icon.
3 SW_SHOWMAXIMIZED Activates a window and displays it as a maximized window.
3 SW_MAXIMIZE Activates a window and displays it as a maximized window.
4 SW_SHOWNOACTIVATE Displays a window in its most recent size and position. The window that is currently active remains active.
5 SW_SHOW Activates a window and displays it in its current size and position.
6 SW_MINIMIZE Minimizes the specified window and activates the top-level window in the system's list.
7 SW_SHOWMINNOACTIVE Displays a window as an icon. The window that is currently active remains active.
8 SW_SHOWNA Displays a window in its current state. The window that is currently active remains active.
9 SW_RESTORE Activates and displays a window. If the window is minimized or maximized, Windows restores it to its original size and position (same as SW_NORMAL ).