uhd: misc tweaks and also msvc compile

2 files changed, 14 insertions, 5 deletions

diff --git a/host/include/uhd/property_tree.hpp b/host/include/uhd/property_tree.hpp
index b20f3b779..c41a129b1 100644
--- a/host/include/uhd/property_tree.hpp
+++ b/host/include/uhd/property_tree.hpp
@@ -31,7 +31,7 @@ namespace uhd{
  * A templated property interface for holding a value
  * and registering callbacks when that value changes.
  */
-template <typename T> class UHD_API property : boost::noncopyable{
+template <typename T> class property : boost::noncopyable{
 public:
     typedef boost::function<void(const T &)> subscriber_type;
     typedef boost::function<T(void)> publisher_type;
@@ -89,6 +89,13 @@ public:
      * \return the current value in the property
      */
     virtual T get(void) const = 0;
+
+    /*!
+     * A property is empty if it has never been set.
+     * A property with a publisher is never empty.
+     * \return true if the property is empty
+     */
+    virtual bool empty(void) const = 0;
 };
 
 /*!
diff --git a/host/include/uhd/property_tree.ipp b/host/include/uhd/property_tree.ipp
index 58ee2339c..868cba475 100644
--- a/host/include/uhd/property_tree.ipp
+++ b/host/include/uhd/property_tree.ipp
@@ -27,7 +27,7 @@
  **********************************************************************/
 namespace uhd{ namespace /*anon*/{
 
-template <typename T> class UHD_API property_impl : public property<T>{
+template <typename T> class property_impl : public property<T>{
 public:
 
     property<T> &coerce(const typename property<T>::coercer_type &coercer){
@@ -59,12 +59,14 @@ public:
     }
 
     T get(void) const{
-        if (_publisher.empty() and _value.get() == NULL) throw uhd::runtime_error(
-            "Called get() on property with an uninitialized value"
-        );
+        if (empty()) throw uhd::runtime_error("Cannot get() on an empty property");
         return _publisher.empty()? *_value : _publisher();
     }
 
+    bool empty(void) const{
+        return _publisher.empty() and _value.get() == NULL;
+    }
+
 private:
     std::vector<typename property<T>::subscriber_type> _subscribers;
     typename property<T>::publisher_type _publisher;