Functions:-This puts time information into a shared memory segment for the ntp daemon to use. Notes based on code as of Tue Apr 6 10:17:55 2010 -0400. static struct shmTime *getShmTime(int unit) This requests a block of shared memory to communicate to the ntp daemon. It returns a pointer to the memory on success or NULL on failure. void ntpshm_init(struct gps_context_t *context, bool enablepps) Attaches all ntp shared memory segments, flagging the availability of the NMEA and 1pps capabilities as appropriate. int ntpshm_alloc(struct gps_context_t *context) This tries to allocate a free ntp shared memory segment.If one is available, initialise it for use and flag it as in use.Returns the segment number on success or -1 on failure. bool ntpshm_free(struct gps_context_t *context, int segment) This tries to release a previously allocated ntp shared memory segment. Indicates the outcome by returning true (success) or false. int ntpshm_put(struct gps_device_t *session, double fixtime) If the shared memory index allocated to the session is valid and the shmTime structure of the session is valid, store the time of the fix.Success is indicated by a return value of 1 and errors are indicated by a return value of 0. int ntpshm_pps(struct gps_device_t *session, struct timeval *tv) This code is only available if the 1PPS function is compiled in.The shared memory structures are checked for validity and if not valid, a 0 is returned.The time received is then checked to be within 100 milliseconds of the PC's internal time and if not, a -1 is returned.The time received is then checked to be within 500 milliseconds of the second boundary and if not, the shared memory structure is advised that lock is lost and a -1 is returned.If good, the time is stored in the shared memory and 1 is returned.