This document describes pvDatabaseCPP, which is a framework for implementing a network accessible database of smart memory resident records. Network access is via pvAccess. The data in each record is a top level PVStructure as defined by pvData. The framework includes a complete implementation of ChannelProvider as defined by pvAccess. The framework can be extended in order to create record instances that implements services. The minimum that an extension must provide is a top level PVStructure and a process method.
For more information about EPICS generally, please refer to the home page of the Experimental Physics and Industrial Control System.
pvDatabaseCPP is one of the components of EPICS Version 7
This document is only a guide to help locate code and documentation related to pvDatabaseCPP It is intended for developers that want to use pvDatabaseCPP.
A guide for developers is available at developerGuide
This guide discusses all the components that are part of an EPICS V4 release. Some understanding of the components and how they are related is necessary in order to develop code that uses pvDatabaseCPP. In particular read everything related to pvDatabase.
pvDatabase has plugin support, which is implemented in pvCopy. pvCopy was originally implemented in pvDataCPP, but pvDatabaseCPP now implements its own version and adds plugin support.
See pvRequest for details.
The developerGuide discusses code in a way that applies to both CPP and C++. For the descriptions of the CPP specific code consult the following sections.
doxygen documentation is available at doxgen
The header files that describe the various components implemented by pvDatabase.
This has the code that implements pvDatabase and pvRecord.
This has the code for the channel provider for pvDatabase.
This has the pvSupport code.
This has the code for processRecord, addRecord, removeRecord, and traceRecord.
This has the code for pvStructureCopy and all the plugin support.
Example code is available as part of this release. exampleCPP
In particular look at the example code mentioned in the following sub-sections.
This has many examples of how to create both soft records and records that implement other functionality.
This shows how to implement a record that has a link to another record
This creates records that have the following features:
It also creates records that can be used by clients to show example of the plugin support.
Shell commands are made available via the standard DBD include mechanism provided by iocCore. The following provide EPICS V4 shell commands:
pvAccessCPP qsrv pvDatabaseCPP
pvDatabaseCPP provides the following iocshell command.
In addition any code that implements a PVRecord must implement an ioc command. Look at the examples in exampleCPP/support to see how to implement shell commands.