Experimental Physics and
Industrial Control System

john sinclair <[email protected]> · Tue, 29 Oct 2002 12:48:12 -0500 (EST)

One stress test I have applied to edm is performing a moderately rapid
succession of connects/disconnects via a channel access server.

I have recently noticed one problem.

The logical code structure is shown below:

global needInit

==========================

main routine:

needInit = false
search_and_connect

do {
  pend io, event
  if ( needInit ) {  // needInit is set in the connect callback
    ca_get_callback(...)
    needInit = false
  }
} until all outstanding io is complete

===========================

connect_callback function (...) {

  if ( pv is connected ) {
    needInit = true
  }
  else {
    needInit = false
  }

}

===========================

get_callback function (
  struct event_handler_args args
) {

  examine args.status

  // status here is sometimes ECA_ANACHRONISM
  // and args.dbr is NULL

}

Has this always been possible? I'm sure I get the connect callback before
the get callback (by examining other data that gets set in the connect
callback {not shown in above simplified example}).

John Sinclair
[email protected]
Oak Ridge National Lab
865-576-6362   865-574-1268 (fax)

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System