setDouble
Sets @key in @settings to @value.
A convenience variant of g_settings_set() for doubles.
It is a programmer error to give a @key that isn't specified as having a 'double' type in the schema for @settings.
Return
true if setting the key succeeded, false if the key was not writable
Since
2.26
Parameters
key
the name of the key to set
value
the value to set it to