37.6. The Event orderer/event builder API
The event builder itself is a loadable Tcl package rather than a program. This allows experiment designers to:
Provide application dependent user interfaces on top of and around those provided by the event builder.
Tailor the operation of the event builder to meet application specific requirements.
37.6.1. Starting the event builder/orderer
The example below is a Tcl script fragment that shows how to start the event builder. The code assumes that the environment variable DAQROOT has been set to the top installation directory of the NSCLDAQ being used (version 10.2 or later).
Example 37-3. Starting the event builder
lappend auto_path [file join $::env(DAQROOT) TclLibs]package require EventBuilder
EVB::Start ?name?
-
Adds the Tcl Library directory of the NSCLDAQ to the
list of directories searched for packages. This could
also have been done by defining the
TCLLIBS environment variable.
TCLLIBS is a space separated list
of directories trees that will be added to
auto_pathwhen tclsh or wish starts. - Loads the event builder Tcl package. This package defines the ::EVB:: namespace. The event builder API lives in this namespace to prevent name conflicts with your application variables and procs.
-
Starts the event builder. The event builder will use
the DAQ Port manager to allocate a Tcp/IP server
port as well as to advertise itself to potential
clients. The optional
nameparameter specifies the event builder name. Note that if you provide a duplicate name,the script will attempt to pop up a Tk dialog prompting you to continue or not. When this proc has returned, the event builder is listening for connections on that port and the client library will be able to find the event builder.
This proc must be called prior to any other procs in the EVB:: namespace.