From 8000ed063777b775843ac40bb800ab183614d68c Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Mon, 4 Jun 2018 13:58:22 -0700
Subject: [PATCH] client.h default ctor for ClientProvider

Allow an invalid ClientProvider to be created
for later assignment.
---
 src/client/client.cpp   | 4 ++++
 src/client/pva/client.h | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/src/client/client.cpp b/src/client/client.cpp
index 0770f84..cdb374b 100644
--- a/src/client/client.cpp
+++ b/src/client/client.cpp
@@ -282,6 +282,7 @@ ClientProvider::~ClientProvider() {}
 std::string
 ClientProvider::name() const
 {
+    if(!impl) throw std::logic_error("Dead Provider");
     return impl->provider->getProviderName();
 }
 
@@ -289,6 +290,7 @@ ClientChannel
 ClientProvider::connect(const std::string& name,
                             const ClientChannel::Options& conf)
 {
+    if(!impl) throw std::logic_error("Dead Provider");
     Guard G(impl->mutex);
     Impl::channels_t::key_type K(name, conf);
     Impl::channels_t::iterator it(impl->channels.find(K));
@@ -309,6 +311,7 @@ ClientProvider::connect(const std::string& name,
 bool ClientProvider::disconnect(const std::string& name,
                                     const ClientChannel::Options& conf)
 {
+    if(!impl) throw std::logic_error("Dead Provider");
     Guard G(impl->mutex);
 
     Impl::channels_t::iterator it(impl->channels.find(std::make_pair(name, conf)));
@@ -320,6 +323,7 @@ bool ClientProvider::disconnect(const std::string& name,
 
 void ClientProvider::disconnect()
 {
+    if(!impl) throw std::logic_error("Dead Provider");
     Guard G(impl->mutex);
     impl->channels.clear();
 }
diff --git a/src/client/pva/client.h b/src/client/pva/client.h
index 556e5ab..840b90b 100644
--- a/src/client/pva/client.h
+++ b/src/client/pva/client.h
@@ -475,6 +475,8 @@ class epicsShareClass ClientProvider
     friend epicsShareFunc ::std::ostream& operator<<(::std::ostream& strm, const ClientProvider& op);
 public:
 
+    //! Construct a null provider.  All methods throw.  May later be assigned from a valid ClientProvider
+    ClientProvider() {}
     /** Use named provider.
      *
      * @param providerName ChannelProvider name, may be prefixed with "clients:" or "servers:" to query