g-action-group-action-parameter-type (group name)

group -- a g-action-group object
name -- a string with the name of the action to query

The g-variant-type parameter type.

Queries the type of the parameter that must be given when activating the named action within the action group.

When activating the action using the g-action-group-activate-action function, the g-variant-type parameter type given to that function must be of the type returned by this function.

In the case that this function returns nil, you must not give any g-variant parameter, but nil instead.

The parameter type of a particular action will never change but it is possible for an action to be removed and for a new action to be added with the same name but a different parameter type. This function does not return nil as expected for an action with no g-variant-type parameter type. Your will get a correct return value using the g-action-map-lookup-action function to get the action from the action group and the g-action-parameter-type function to get the parameter type.