Together with GtkPlug, GtkSocket provides the ability
to embed widgets from one process into another process
in a fashion that is transparent to the user. One
process creates a GtkSocket widget and, passes the
that widget's window ID to the other process,
which then creates a GtkPlug with that window ID.
Any widgets contained in the GtkPlug then will appear
inside the first applications window. The socket's window ID is obtained by using
gtkSocketGetId. Before using this function,
the socket must have been realized, and for hence,
have been added to its parent. Obtaining the window ID of a socket.
socket <- gtkSocket()
parent$add(socket) ## The following call is only necessary if one of
## the ancestors of the socket is not yet visible.
socket$realize()
print(paste("The ID of the sockets window is", socket$getId()))
Note that if you pass the window ID of the socket to another
process that will create a plug in the socket, you
must make sure that the socket widget is not destroyed
until that plug is created. Violating this rule will
cause unpredictable consequences, the most likely
consequence being that the plug will appear as a
separate toplevel window. You can check if the plug
has been created by examining the
plug_window field of the
GtkSocket structure. If this field is non-NULL,
then the plug has been successfully created inside
of the socket. When GTK+ is notified that the embedded window has been
destroyed, then it will destroy the socket as well. You
should always, therefore, be prepared for your sockets
to be destroyed at any time when the main event loop
is running. To prevent this from happening, you can
connect to the "plug-removed" signal. The communication between a GtkSocket and a GtkPlug follows the
XEmbed (http://www.freedesktop.org/standards/xembed-spec)
protocol. This protocol has also been implemented in other toolkits, e.g.
Qt, allowing the same level of integration
when embedding a Qt widget in GTK or vice versa.
A socket can also be used to swallow arbitrary
pre-existing top-level windows using gtkSocketSteal,
though the integration when this is done will not be as close
as between a GtkPlug and a GtkSocket. PLEASE NOTE: The GtkPlug and GtkSocket widgets are currently not available
on all platforms supported by GTK+.