g-option-context-main-group (context)

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

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