location to store a UTF-8 encoded string of text holding context around the insertion point. If the function returns %TRUE, then you must free the result stored in this location with g_free().
location to store byte index of the insertion cursor within @text.
%TRUE if surrounding text was provided; in this case you must free the result stored in *text.
Retrieves context around the insertion point. Input methods typically want context in order to constrain input text based on existing text; this is important for languages such as Thai where only some sequences of characters are allowed.
This function is implemented by emitting the GtkIMContext::retrieve_surrounding signal on the input method; in response to this signal, a widget should provide as much context as is available, up to an entire paragraph, by calling gtk_im_context_set_surrounding(). Note that there is no obligation for a widget to respond to the ::retrieve_surrounding signal, so input methods must be prepared to function without context.