Initializes the IUP toolkit. Must be called before any other IUP function.


int IupOpen(int *argc, char ***argv); [in C]
[There is no equivalent in Lua]

argc and argv: are the same as the application "main" function function. Some parameters processed by the driver can be removed so the address is necessary. They can be NULL. (Since 2.7)

Returns: IUP_OPENED (already opened), IUP_ERROR or IUP_NOERROR. Only in UNIX can fail to open, because X-Windows may be not initialized.


In Windows, CoInitializeEx(COINIT_APARTMENTTHREADED) and InitCommonControlsEx(ICC_WIN95_CLASSES) functions are called.

In Motif, XtOpenApplication function is called.

For a more detailed explanation on the system control, please refer to Guide / System Control.

Environment Variables

The toolkit's initialization depends also on platform-dependent environment variables, see each driver documentation.


When this variable is set to NO, IUP will generate a message in console indicating the driver’s version when initializing. Default: YES.


When this variable is set to YES, IUP generates a message dialog indicating the driver's version when initializing.  Default: NO.

Lua Binding 

This function should be called by the host program and before the IupLua initialization function iuplua_open. If not the IupLua initialization function will call it.

See Also

iuplua_open, IupClose, Guide / System Control