Initializes the IUP toolkit. Must be called before any other IUP function.
int IupOpen(void); [in C] [There is no equivalent in Lua]
This function returns IUP_ERROR or IUP_NOERROR.
The IupOpen function in the Windows driver initializes OLE through the function OleInitialize; IupClose calls OleUninitialize.
The toolkit's initialization depends on several platform-dependent environment variables.
For a more detailed explanation on the system control, please refer to Guide / System Control.
Lua: This function must be called by the host program and before the Binding Lua initialization function, iuplua_open.