glib:option-context-main-group (context)

context -- a g:option-context instance
group -- a g:option-group instance

The g:option-context-main-group function returns the main group of context. The (setf g:option-context-main-group) function sets a g:option-group instance as main group of the option context. This has the same effect as calling the g:option-context-add-group function, the only difference is that the options in the main group are treated differently when generating --help output.