A question about how to send message in the callback function

[赵欢 <zhaohuan@sinap.ac.cn>]

 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 monitor’s 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