/**
 * RIL_REQUEST_REGISTRATION_STATE
 *
 * Request current registration state
 *
 * "data" is NULL
 * "response" is a "char **"
 * ((const char **)response)[0] is registration state 0-6,
 *              0 - Not registered, MT is not currently searching
 *                  a new operator to register
 *              1 - Registered, home network
 *              2 - Not registered, but MT is currently searching
 *                  a new operator to register
 *              3 - Registration denied
 *              4 - Unknown
 *              5 - Registered, roaming
 *             10 - Same as 0, but indicates that emergency calls
 *                  are enabled.
 *             12 - Same as 2, but indicates that emergency calls
 *                  are enabled.
 *             13 - Same as 3, but indicates that emergency calls
 *                  are enabled.
 *             14 - Same as 4, but indicates that emergency calls
 *                  are enabled.
 *
 * ((const char **)response)[1] is LAC if registered on a GSM/WCDMA system or
 *                              NULL if not.Valid LAC are 0x0000 - 0xffff
 * ((const char **)response)[2] is CID if registered on a * GSM/WCDMA or
 *                              NULL if not.
 *                                 Valid CID are 0x00000000 - 0xffffffff
 *                                    In GSM, CID is Cell ID (see TS 27.007)
 *                                            in 16 bits
 *                                    In UMTS, CID is UMTS Cell Identity
 *                                             (see TS 25.331) in 28 bits
 * ((const char **)response)[3] indicates the available radio technology 0-7,
 *                                  0 - Unknown, 1 - GPRS, 2 - EDGE, 3 - UMTS,
 *                                  4 - IS95A, 5 - IS95B, 6 - 1xRTT,
 *                                  7 - EvDo Rev. 0, 8 - EvDo Rev. A,
 *                                  9 - HSDPA, 10 - HSUPA, 11 - HSPA
 * ((const char **)response)[4] is Base Station ID if registered on a CDMA
 *                              system or NULL if not.  Base Station ID in
 *                              decimal format
 * ((const char **)response)[5] is Base Station latitude if registered on a
 *                              CDMA system or NULL if not. Base Station
 *                              latitude is a decimal number as specified in
 *                              3GPP2 C.S0005-A v6.0. It is represented in
 *                              units of 0.25 seconds and ranges from -1296000
 *                              to 1296000, both values inclusive (corresponding
 *                              to a range of -90∞ to +90∞).
 * ((const char **)response)[6] is Base Station longitude if registered on a
 *                              CDMA system or NULL if not. Base Station
 *                              longitude is a decimal number as specified in
 *                              3GPP2 C.S0005-A v6.0. It is represented in
 *                              units of 0.25 seconds and ranges from -2592000
 *                              to 2592000, both values inclusive (corresponding
 *                              to a range of -180∞ to +180∞).
 * ((const char **)response)[7] is concurrent services support indicator if
 *                              registered on a CDMA system 0-1.
 *                                   0 - Concurrent services not supported,
 *                                   1 - Concurrent services supported
 * ((const char **)response)[8] is System ID if registered on a CDMA system or
 *                              NULL if not. Valid System ID are 0 - 32767
 * ((const char **)response)[9] is Network ID if registered on a CDMA system or
 *                              NULL if not. Valid System ID are 0 - 65535
 * ((const char **)response)[10] is the TSB-58 Roaming Indicator if registered
 *                               on a CDMA or EVDO system or NULL if not. Valid values
 *                               are 0-255.
 * ((const char **)response)[11] indicates whether the current system is in the
 *                               PRL if registered on a CDMA or EVDO system or NULL if
 *                               not. 0=not in the PRL, 1=in the PRL
 * ((const char **)response)[12] is the default Roaming Indicator from the PRL,
 *                               if registered on a CDMA or EVDO system or NULL if not.
 *                               Valid values are 0-255.
 * ((const char **)response)[13] if registration state is 3 (Registration
 *                               denied) this is an enumerated reason why
 *                               registration was denied.  See 3GPP TS 24.008,
 *                               10.5.3.6 and Annex G.
 *                                 0 - General
 *                                 1 - Authentication Failure
 *                                 2 - IMSI unknown in HLR
 *                                 3 - Illegal MS
 *                                 4 - Illegal ME
 *                                 5 - PLMN not allowed
 *                                 6 - Location area not allowed
 *                                 7 - Roaming not allowed
 *                                 8 - No Suitable Cells in this Location Area
 *                                 9 - Network failure
 *                                10 - Persistent location update reject
 *
 * Please note that registration state 4 ("unknown") is treated
 * as "out of service" in the Android telephony system
 *
 * Registration state 3 can be returned if Location Update Reject
 * (with cause 17 - Network Failure) is received repeatedly from the network,
 * to facilitate "managed roaming"
 *
 * Valid errors:
 *  SUCCESS
 *  RADIO_NOT_AVAILABLE
 *  GENERIC_FAILURE
 */
#define RIL_REQUEST_REGISTRATION_STATE 20