Returns the value associated with @key under @group_name as a
boolean.
If @key cannot be found then %FALSE is returned and @error is set
to #G_KEY_FILE_ERROR_KEY_NOT_FOUND. Likewise, if the value
associated with @key cannot be interpreted as a boolean then %FALSE
is returned and @error is set to #G_KEY_FILE_ERROR_INVALID_VALUE.
Returns the value associated with @key under @group_name as a boolean.
If @key cannot be found then %FALSE is returned and @error is set to #G_KEY_FILE_ERROR_KEY_NOT_FOUND. Likewise, if the value associated with @key cannot be interpreted as a boolean then %FALSE is returned and @error is set to #G_KEY_FILE_ERROR_INVALID_VALUE.