glib:key-file-boolean (keyfile group key)

keyfile -- a g:key-file instance
group -- a string for the group name
key -- a string for the key
value -- a boolean for the value associated with the key

Gets or sets the value associated with key under group as a boolean. If key cannot be found when it is set, the key is created. If key cannot be found when it is retrieved, nil is returned. Likewise, if the value associated with key cannot be interpreted as a boolean then nil is returned.