pvac: add sync. monitor

examples/minimonitor.cpp

@@ -0,0 +1,102 @@
+/*
+ * Copyright information and license terms for this software can be
+ * found in the file LICENSE that is included with the distribution
+ */
+// The simplest possible PVA monitor
+
+#include <iostream>
+
+#if !defined(_WIN32)
+#include <signal.h>
+#define USE_SIGNAL
+#endif
+
+#include <epicsEvent.h>
+
+#include <pva/client.h>
+
+static volatile bool done;
+
+#ifdef USE_SIGNAL
+static pvac::MonitorSync * volatile subscription;
+static
+void handler(int num)
+{
+    (void)num;
+    done = true;
+    if(subscription)
+        subscription->wake();
+}
+#endif
+
+int main(int argc, char *argv[])
+{
+    try {
+        if(argc<=1) {
+            std::cerr<<"Usage: "<<argv[0]<<" <pvname>\n";
+            return 1;
+        }
+
+        pvac::ClientProvider provider("pva");
+
+        pvac::ClientChannel channel(provider.connect(argv[1]));
+
+        pvac::MonitorSync mon(channel.monitor());
+
+#ifdef USE_SIGNAL
+        subscription = &mon;
+        signal(SIGINT, handler);
+        signal(SIGTERM, handler);
+        signal(SIGQUIT, handler);
+#endif
+
+        int ret = 0;
+
+        while(!done) {
+            if(!mon.wait()) // updates mon.event
+                continue;
+
+            switch(mon.event.event) {
+            // Subscription network/internal error
+            case pvac::MonitorEvent::Fail:
+                std::cerr<<mon.name()<<" : Error : "<<mon.event.message<<"\n";
+                ret = 1;
+                done = true;
+                break;
+            // explicit call of 'mon.cancel' or subscription dropped
+            case pvac::MonitorEvent::Cancel:
+                std::cout<<mon.name()<<" <Cancel>\n";
+                done = true;
+                break;
+            // Underlying channel becomes disconnected
+            case pvac::MonitorEvent::Disconnect:
+                std::cout<<mon.name()<<" <Disconnect>\n";
+                break;
+            // Data queue becomes not-empty
+            case pvac::MonitorEvent::Data:
+                // We drain event FIFO completely
+                while(mon.poll()) {
+                    std::cout<<mon.name()<<" : "<<mon.root;
+                }
+                // check to see if more events might be sent
+                if(mon.complete()) {
+                    done = true;
+                    std::cout<<mon.name()<<" : <Complete>\n";
+                }
+                break;
+            }
+        }
+
+#ifdef USE_SIGNAL
+        signal(SIGINT, SIG_DFL);
+        signal(SIGTERM, SIG_DFL);
+        signal(SIGQUIT, SIG_DFL);
+        subscription = 0;
+#endif
+
+        return ret;
+    }catch(std::exception& e){
+        std::cerr<<"Error: "<<e.what()<<"\n";
+        return 1;
+    }
+}