Fix nullptr defined as 0 on g++.

SafeInt3.hpp used an invalid check to determine wether nullptr should be defined as 0 with g++ compiler. Checking that we use c++11 or above fixed the issue.
However, using a valid check broke the compilation because boost::function cannot be resetted by assigning a nullptr to it. Using default constructed boost::function for reset fixed this.

Author: Simon Lepasteur

Release/include/cpprest/details/SafeInt3.hpp

@@ -118,8 +118,8 @@ Version 3.0
 #define NEEDS_NULLPTR_DEFINED 1
 #endif
 #else
-// Let everything else trigger based on whether we have nullptr_t
-#if defined nullptr_t
+// Let everything else trigger based on whether we use c++11 or above
+#if __cplusplus >= 201103L
 #define NEEDS_NULLPTR_DEFINED 0
 #else
 #define NEEDS_NULLPTR_DEFINED 1

Release/libs/websocketpp/websocketpp/transport/asio/connection.hpp

@@ -442,8 +442,8 @@ class connection : public config::socket_type::socket_con_type {
         if (ec) {
             // reset the handlers to break the circular reference:
             // this->handler->this
-            m_async_read_handler = _WEBSOCKETPP_NULLPTR_TOKEN_;
-            m_async_write_handler = _WEBSOCKETPP_NULLPTR_TOKEN_;
+            m_async_read_handler = async_read_handler{};
+            m_async_write_handler = async_write_handler{};
         }
 
         return ec;
@@ -969,12 +969,12 @@ class connection : public config::socket_type::socket_con_type {
 		// Reset cached handlers now that we won't be reading or writing anymore
 		// These cached handlers store shared pointers to this connection and
 		// will leak the connection if not destroyed.
-		m_async_read_handler = _WEBSOCKETPP_NULLPTR_TOKEN_;
-		m_async_write_handler = _WEBSOCKETPP_NULLPTR_TOKEN_;
-		m_init_handler = _WEBSOCKETPP_NULLPTR_TOKEN_;
+		m_async_read_handler = async_read_handler{};
+		m_async_write_handler = async_write_handler{};
+		m_init_handler = init_handler{};
 
-        m_read_handler = _WEBSOCKETPP_NULLPTR_TOKEN_;
-        m_write_handler = _WEBSOCKETPP_NULLPTR_TOKEN_;
+        m_read_handler = read_handler{};
+        m_write_handler = write_handler{};
 
         timer_ptr shutdown_timer;
         shutdown_timer = set_timer(