Experimental Physics and
Industrial Control System

"Kasemir, Kay" <[email protected]> · Tue, 24 Mar 2009 14:54:28 -0400

On 3/24/09 14:43 , "GaryCarr" <[email protected]> wrote:
> Are there any limitations that apply to one, and not the other?
In case you depend on the exact verbiage of error messages,
they differ. CAJ tends to give more specific ones like
access permission error while JCA might just report write error.

CAJ seems to be perfectly fine with multithreaded access,
while I've run into deadlocks when for example calling JNI JCA
from one thread, trying to remove a monitor, while a JNI JCA
value update arrived on another thread for another PV.
I think Jeff said that the CA client library itself does not
lock in those cases, to the lock might be inside the JNI code,
but in any case you must not lock anything in your code
when dealing with JNI JCA because that can result in deadlocks.

Thanks,
-Kay 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System