Creates or changes the specified key and its associated double value under the form: 'Key$ = Value' in the preference file, previously created with CreatePreferences() or opened with OpenPreferences().
Key$ The key name to write. If PreferenceGroup() has been used, then the write is restricted to the current group. If the key was already created, its associated value is replaced with the new specified value. Value The double value to associate with the key.
See the example at WritePreferenceFloat()
WritePreferenceFloat(), WritePreferenceInteger(), WritePreferenceLong(), WritePreferenceQuad(), WritePreferenceString()