Re: threading in asyn device support

[Andrew Johnson <anj@aps.anl.gov>]

On 09/19/2013 10:38 AM, Ralph Lange wrote:
> On 19.09.2013 17:32, Vikram Bhagat wrote:
> >     Thanks for explanation.  One more question.
> > after completion of task how to delete Thread in EPICS (epicsThread),
> > or it is not required in EPICS?
>
>  From the Application Developer's Guide, chapter 20.14 epicsThread:
>
>     Life cycle - A thread starts life as a result of a call to
>     epicsThreadCreate. It terminates when the thread function
>     returns. It should not return until it has released all resources it
>     uses. If a thread is expected to terminate as a
>     natural part of its life cycle then the thread function must return.

One additional point; there is a C++ API (documented just below the C 
API in the AppDevGuide) which is slightly different to the C API that 
Ralph mentions above.  If you choose to use the C++ API you create a 
class epicsThread object for the thread which must be deleted after 
you've finished with it.

Note that there is a simpler and alternative to creating your own thread 
which uses less memory; assuming that this is code that runs inside an 
IOC you might want to look at the Callback API which is documented in 
section 16.2 of the Application Developers Guide.  It provides a 
general-purpose task for executing jobs in a common thread, and you can 
just queue your task to be executed immediately or after some delay.

- Andrew
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