Re: [gpsd-dev] gpsd client maintainance

[Eric S. Raymond]

devendra.aaru <address@hidden>:
> Hello,
> 
> Gpsd kills the client (or subscriber) if its idle for more than 60
> sec, i think this is just used to maintain the client table and to
> serve as many client requests as possible. Please correct me if i am
> wrong.
> 
> thanks

>From gpsd.c:

/*
 * Timeout policy.  We can't rely on clients closing connections
 * correctly, so we need timeouts to tell us when it's OK to
 * reclaim client fds.  COMMAND_TIMEOUT fends off programs
 * that open connections and just sit there, not issuing a WATCH or
 * doing anything else that triggers a device assignment.  Clients
 * in watcher or raw mode that don't read their data will get dropped
 * when throttled_write() fills up the outbound buffers and the
 * NOREAD_TIMEOUT expires.
 *
 * RELEASE_TIMEOUT sets the amount of time we hold a device
 * open after the last subscriber closes it; this is nonzero so a
 * client that does open/query/close will have time to come back and
 * do another single-shot query, if it wants to, before the device is
 * actually closed.  The reason this matters is because some Bluetooth
 * GPSes not only shut down the GPS receiver on close to save battery
 * power, they actually shut down the Bluetooth RF stage as well and
 * only re-wake it periodically to see if an attempt to raise the
 * device is in progress.  The result is that if you close the device
 * when it's powered up, a re-open can fail with EIO and needs to be
 * tried repeatedly.  Better to avoid this...
 *
 * DEVICE_REAWAKE says how long to wait before repolling after a zero-length
 * read. It's there so we avoid spinning forever on an EOF condition.
 *
 * DEVICE_RECONNECT sets interval on retries when (re)connecting to
 * a device.
 */
#define COMMAND_TIMEOUT         60*15
#define NOREAD_TIMEOUT          60*3
#define RELEASE_TIMEOUT         60
#define DEVICE_REAWAKE          0.01
#define DEVICE_RECONNECT        2

-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>