Ipc

Interprocess communication in Hall B is based on package located in $CLON/src/ipc. Currently it is based on ActiveMQ, which can be replaced with another messager if necessary, for example jlab-developed xMsg. Switching between messagers is done by changing $CLON/src/Makefile.include and recompiling entire $CLON area. ActiveMQ or any other messager must be installed in /usr/local/src area.

Top level classes can be found in $CLON/src/ipc/ipc.s/ipc_lib.h, test program is $CLON/src/ipc/main/ipc_client.cc.

User code includes following:

#include "ipc_lib.h"

#include "MessageActionControl.h"

#include "MessageActionXXXX.h" // XXXX is particular listener, like MessageActionEPICS.h

IpcServer &server = IpcServer::Instance(); // get ipc server instance, it is implemented as singleton

main()
{
  // following call sets topic for sender ("par1.par2.par3.par4") and receiver ("par1.par2.par5.par6")
  // 1st and 2nd params - usually EXPID and SESSION, or EXPID and NULL
  // 3rd and 4th params - for sender only, for example 'epics' and 'dbrouter'
  // 5th and 6th params (optional) - for receiver only, for example 'epics' and '*' (listen for messages)
  server.init(getenv("EXPID"), NULL, (char *)"epics", (char *)"myname", (char *)"epics", (char *)"*");

  MessageActionControl  *control = new MessageActionControl((char *)"myname");
  MessageActionXXXX        *xxxx = new MessageActionXXXX();

  server.addActionListener(control);
  server.addActionListener(xxxx);

  server << clrm << ...stuff... << endm;

  server.close();
}