Re: Questions about channel access C API programming

[Wang Xiaoqiang via Tech-talk <tech-talk@aps.anl.gov>]

Hi,

Call ca_flush_io after ca_put.

1. ca_task_initialize is the old API, and creates a non-preemptive context.
2. DBR is for request and DBF is for field type. But plain DBR_XXX has 
the same value as DBF_XXX.
Best
Xiaoqiang

On 3/5/19 3:08 PM, Abdalla Ahmad via Tech-talk wrote:
> Hi
>
> The attached C file is a snippet from a Qt project. In the project there 
> was a function that writes values to many PVs in a loop. What was 
> happening is that some PVs do not get their new value updated 
> immediately but after 3 or 4 seconds. The code shows a similar behavior, 
> two consecutive "ca_put" calls, and the same behavior occurs. I 
> double-checked the database (included in the comments) but there is 
> nothing wrong. I tried to use ca_context_ or ca_task_ but the project 
> crashes maybe because the QE framework is already handling low-level CA. 
> What am I missing here?
> Another two questions came up:
>
> 1.What is the difference between ca_task_initialize and ca_context_create?
>
> 2.What is the difference between request types (DBR_) and field types 
> (DBF_)?
> P.S.: We are using Base 3.15.6
>
> Best Regards,
>
> Abdalla Ahmad
>
> Control Engineer
>
> SESAME
>
> Allan, Jordan.
>
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>
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