c_gtk_action_group_add_radio_actions_full

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
__gshared extern (C)
void function(GtkActionGroup* actionGroup, GtkRadioActionEntry* entries, uint nEntries, int value, GCallback onChange, void* userData, GDestroyNotify destroy) c_gtk_action_group_add_radio_actions_full;

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