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Subject: RE: A question about how to send message in the callback function
From: "Jeff Hill" <johill@lanl.gov>
To: 'ÕÔ»¶' <zhaohuan@sinap.ac.cn>, <core-talk@aps.anl.gov>
Date: Mon, 27 Mar 2006 08:26:40 -0700

Hello ZHAO HUAN,

 

One must call ca_attach_context from the satellite thread after calling ca_current_context in the main (CA client context initiating) thread. Also see CA Client Contexts and Application Specific Auxiliary Threads in the CA Reference Manual. Also see Thread Safety and Preemptive Callback to User Code.

 

PS: If you enable preemptive callback be careful to protect your data structures against simultaneous use from multiple threads.

 

Jeff

 

 

-----Original Message-----
From: ÕÔ»¶ [mailto:zhaohuan@sinap.ac.cn]
Sent: Sunday, March 26, 2006 8:52 PM
To: core-talk@aps.anl.gov
Subject: A question about how to send message in the callback function

 

 Dear everybody:
 
 
     I am a novice to EPICS. I want to develop a simple
 application which will have functions of put,get and monitor channels in
 IOC. I have installed  EPICS Base R3.14.5 in a PC/Windows .
 
 
Now, I face a puzzle.  I cteate a auxiliary thread. And in the auxiliary thread, I do an operation of create a 
 
monitor(ca_create_subscription). Then in the monitors callback faction, I make an operation of sendmessage. The problem 
 
is coming. The runing programe is dead at the sendmessage step.
 
       
       If somebody have the experience,  tell me what is wrong in my application, and how can I resolve it.
 
  Thanks
 
  ZHAO HUAN
 
 Shanghai Institute of Applied Physics
 Chinese Academy of Sciences
 P. O. Box 800-204, Shanghai 201800, P. R. China
 Tel: +86-21-59553146

 


References:
A question about how to send message in the callback function 赵欢

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