Add boost asio async connection

Add an async connection and example of usage. This
connection inherits the bus object and allows async
method calls using boost asio. Most of these concepts
are from boost-dbus.

Change-Id: I33b5349d543c9ff4b6ee1ce15346c709c052e1ae
Tested: Compiled and ran asio-example on bmc.
Signed-off-by: James Feist <james.feist@linux.intel.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/sdbusplus/message.hpp b/sdbusplus/message.hpp
index 6b58099..d6b5aa7 100644
--- a/sdbusplus/message.hpp
+++ b/sdbusplus/message.hpp
@@ -193,6 +193,15 @@ class message
         return _intf->sd_bus_message_is_method_error(_msg.get(), nullptr);
     }
 
+    /** @brief Get the errno from the message.
+     *
+     *  @return The errno of the message.
+     */
+    int get_errno()
+    {
+        return sd_bus_message_get_errno(_msg.get());
+    }
+
     /** @brief Get the transaction cookie of a message.
      *
      * @return The transaction cookie of a message.
@@ -254,12 +263,13 @@ class message
 
     friend struct sdbusplus::bus::bus;
 
-  private:
     /** @brief Get a pointer to the owned 'msgp_t'. */
     msgp_t get()
     {
         return _msg.get();
     }
+
+  private:
     sdbusplus::SdBusInterface* _intf;
     details::msg _msg;
 };