Modified the read and write functions to handle desynchronization events.

Added a new exception to be able to detect desynchronization events.

src/dynamixel.h

@@ -10,6 +10,8 @@
 #include <string>
 #include <vector>
 
+const int NUM_RETRIES=10;
+
 /**
  * \brief 
  *

src/dynamixelexceptions.cpp

@@ -5,6 +5,7 @@
 
 const std::string dynamixel_error_message="Dynamixel error - ";
 const std::string dynamixel_server_error_message="Dynamixel server error - ";
+const std::string dynamixel_sync_error="Dynamixel synchronization event";
 
 CDynamixelException::CDynamixelException(const std::string& where,const std::string &error_msg,int dev_id):CException(where,dynamixel_error_message)
 {
@@ -33,6 +34,11 @@ unsigned char CDynamixelAlarmException::get_alarm(void)
   return this->alarm;
 }
 
+CDynamixelSyncException::CDynamixelSyncException(const std::string &error_msg):CException("",dynamixel_sync_error)
+{
+  this->error_msg+=error_msg;
+}
+
 CDynamixelServerException::CDynamixelServerException(const std::string& where,const std::string &error_msg):CException(where,dynamixel_server_error_message)
 {
   this->error_msg+=error_msg;

src/dynamixelexceptions.h

@@ -86,6 +86,32 @@ class CDynamixelAlarmException : public CException
     unsigned char get_alarm(void);
 };
 
+/**
+ * \brief Dynamixel Synchronization exception
+ * 
+ * This class is used to report synchronization errors in the communication with the 
+ * dynamixel devices. This exception is thrown when there is some data loss in a 
+ * read or write operation, and it is impossible to reset the communication after
+ * a given number of retries.
+ *
+ */
+class CDynamixelSyncException : public CException
+{
+  public:
+    /**
+     * \brief Class constructor 
+     * 
+     * This constructor generates only a standard error message which is 
+     * "Dynamixel Synchronization error - ". The base
+     * class constructor is called, so the same prefix is appended at the 
+     * beginning to label the message as an exception.
+     * 
+     * \param error_msg a null terminated string with the details of the error.
+     */
+    CDynamixelSyncException(const std::string &error_msg);
+};
+
+
 /**
  * \brief Dynamixel server exception
  *