Queries the this's country calling code and optionally stores the country calling code's origin in
source.
For instance when parsing "+1-617-5423789" this function would return one and assing E_PHONE_NUMBER_COUNTRY_FROM_FQTN to source
.
| this |
the phone number to query |
| source |
an optional location for storing the phone number's origin, or |
|
A valid country calling code, or zero if no code is known. |