On 11.04.2016 11:04, Philippe Leuba wrote:
Hi,
First, I want to congratulate you for this very good and efficient
library and the accompanying Test Manager and DLS.
Thank you :)
But I face some issues:
- pdserv_parameter allows defining an access mode, but I did not see any
effect in Test Manager
At the moment the access mode is not used. It is reserved for future use.
- pdserv_parameter allows defining a callback to have a chance to
modify data before copying it, is the updated value expected to be
reported back to Test Manager ?
Test Manager will always get the updated value.
- pdserv_event_set allows setting and resetting an event, like a state.
How to deal with a punctual event, if we set it and reset it
immediately, it seems not to be sent ?
pdserv_event_set() is used to report "process errors", such as
monitoring whether a value exceeds a limit or a timer has timed out
waiting for something to occur. It converts a signal, aka a stream of
values, into an event with a time stamp.
The event's state is managed internally for every element of the vector.
A change from false (the default state) from a previous call to true in
the current call will set the event. Likewise a change from true to
false will reset the event. Any change is logged to syslog, as well as
notifying clients such as dls, TestManager and pdcom clients.
Calling pdserv_event_set() with no change in the "state" parameter from
one call to another has no effect.
A typical use is inside your cyclic loop:
<code>
while (true) {
// ...
// read pressure from sensor
// ..
pdserv_event_set(overpressure_event, 0, pressure > 5, current_time);
// ...
pdserv_update_statistics(...);
pdserv_update(...);
sleep(delay);
}
</code>
From the description above, two consecutive calls in the same
calculation cycle, once with true and once with false, does not make
much sense and the result thereof is not guaranteed. There can only be
one change in one calculation cycle.
Best regards
Philippe Leuba
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