add example RPC server/client

example/rpc_client.cpp

@@ -0,0 +1,49 @@
+/**
+ * Copyright - See the COPYRIGHT that is included with this distribution.
+ * pvxs is distributed subject to a Software License Agreement found
+ * in file LICENSE that is included with this distribution.
+ */
+/**
+ * Run in conjunction with the rpc_server example
+ *
+ *   ./rpc_server mypv
+ *
+ * Then in another shell run:
+ *
+ *   ./rpc_client mypv 1 2
+ */
+
+#include <iostream>
+
+#include <pvxs/client.h>
+#include <pvxs/log.h>
+
+using namespace pvxs;
+
+int main(int argc, char* argv[])
+{
+    if(argc<4) {
+        std::cerr<<"Usage: "<<argv[0]<<" <pvname> <lhs> <rhs>\n";
+        return 1;
+    }
+
+    // Read $PVXS_LOG from process environment and update
+    // logging configuration.  eg.
+    //    export PVXS_LOG=*=DEBUG
+    // makes a lot of noise.
+    logger_config_env();
+
+    // Create a client context
+    client::Context ctxt(client::Config::fromEnv()
+                         .build());
+
+    auto reply(ctxt.rpc(argv[1])
+                   .arg("lhs", argv[2])
+                   .arg("rhs", argv[3])
+                   .exec()
+                   ->wait(5.0));
+
+    std::cout<<"Reply\n"<<reply;
+
+    return 0;
+}