Implement some PMIx C++ bindings

pmix::init()
pmix::finalize()
pmix::publish()
pmix::initialized()
pmix::get_version()

and supporting data structures.

fairmq/plugins/PMIx/PMIxPlugin.h

@@ -0,0 +1,94 @@
+/********************************************************************************
+ *    Copyright (C) 2019 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *              GNU Lesser General Public Licence (LGPL) version 3,             *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+
+#ifndef FAIR_MQ_PLUGINS_PMIX
+#define FAIR_MQ_PLUGINS_PMIX
+
+#include "PMIx.hpp"
+
+#include <fairmq/Plugin.h>
+#include <fairmq/Version.h>
+#include <FairMQLogger.h>
+
+#include <string>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <sys/types.h>
+#include <unistd.h>
+#include <unordered_map>
+#include <vector>
+
+namespace fair
+{
+namespace mq
+{
+namespace plugins
+{
+
+struct ConnectingChannel
+{
+    ConnectingChannel()
+        : fSubChannelAddresses()
+        , fValues()
+    {}
+
+    std::vector<std::string> fSubChannelAddresses;
+    std::unordered_map<uint64_t, std::string> fValues;
+};
+
+class PMIxPlugin : public Plugin
+{
+  public:
+    PMIxPlugin(const std::string& name,
+         const Plugin::Version version,
+         const std::string& maintainer,
+         const std::string& homepage,
+         PluginServices* pluginServices);
+    ~PMIxPlugin();
+    auto PMIxClient() const -> std::string 
+    {
+        std::stringstream ss;
+        ss << "PMIx client(pid=" << fPid << ")";
+        return ss.str();
+    }
+
+  private:
+    pmix::proc fProc;
+    pid_t fPid;
+    std::unordered_map<std::string, std::vector<std::string>> fBindingChannels;
+    std::unordered_map<std::string, ConnectingChannel> fConnectingChannels;
+
+    auto FillChannelContainers() -> void;
+    auto PublishBoundChannels() -> void;
+};
+
+Plugin::ProgOptions PMIxProgramOptions()
+{
+    boost::program_options::options_description options{"PMIx Plugin"};
+    options.add_options()(
+        "pmix-dummy", boost::program_options::value<int>()->default_value(0), "Dummy.");
+    return options;
+}
+
+REGISTER_FAIRMQ_PLUGIN(
+    PMIxPlugin,                                  // Class name
+    pmix,                                        // Plugin name (string, lower case chars only)
+    (Plugin::Version{FAIRMQ_VERSION_MAJOR,
+                     FAIRMQ_VERSION_MINOR,
+                     FAIRMQ_VERSION_PATCH}),     // Version
+    "FairRootGroup <fairroot@gsi.de>",           // Maintainer
+    "https://github.com/FairRootGroup/FairMQ",   // Homepage
+    PMIxProgramOptions                           // custom program options for the plugin
+)
+
+} /* namespace plugins */
+} /* namespace mq */
+} /* namespace fair */
+
+#endif /* FAIR_MQ_PLUGINS_PMIX */