Poller.tcl
Common pattern that kept coming up when talking to devices.
- Send a "request for status" message to the device
- Wait until the device has had sufficient time to process the request and respond to us
- Read the response
- If there was a response, postpone the "timeout" action
- Go back to polling
- If the timeout action ever fires, stop the polling cycle
Example Usage:
package require poller
proc send_request {} {
puts "send the 'request status' message to the device."
}
proc read_response {} {
puts "read the status response from the device, if we got back what we wanted, postpone the timeout."
}
proc handle_timeout {} {
puts "we timed out, so do something else like switch to another port and start polling there."
}
poller create myPoller 1000 10000 send_request read_response handle_timeout
myPoller start
How to make it available for use:
- Take the Tcl module file and drop it into
<TclInstallRoot>\lib\tcl8\8.6\ - Rename it to poller-0.0.1.tm
package require poller