# PvaClientProcess

pvaClientProcess is a synchronous wrapper for the pvAccess::ChannelProcess API, which is a callback based API. Thus it is easier to use than pvAccess::ChannelProcess itself.

An instance of PvaClientProcess is created via a call to one of the followimg:

    class PvaClientChannel
    ...
    {
    ...
        PvaClientProcessPtr createProcess(std::string const & request = "");
        PvaClientProcessPtr createProcess(epics::pvData::PVStructurePtr const &  pvRequest);
    ...
    };
    An instance of PvaClientProcess connects to a single channel.
    PvaClientProcess has both synchronous methods, which block, and non blocking methods.

    PvaClientChannel has methods:

    connect             Calls issueConnect and then waitConnect.
    issueConnect        issues a request to the server to create the server side of ChannelPut.
    waitConnect         blocks until server responds that it has created the ChannelPut.
    process             Calls issueProcess and then waitProcess.
    issueProcess        issues a process request to the server.
    waitProcess         waits until the server send a message that the process is complete.

    issueConnect and issueProcess do not block.
    All other methods can block.