How to insert value in a TIMESTAMP database field with mysqlpp

I have a database table with a timestamp field, like so:

DROP TABLE IF EXISTS `starstable`.`student_task`;
CREATE TABLE  `starstable`.`student_task` (
  `studentTaskId` int(9) unsigned NOT NULL auto_increment,
  `taskId` int(9) unsigned NOT NULL,
  `objectId` bigint(20) unsigned NOT NULL,
  `variable1` int(9) unsigned default NULL,
  `variable2` int(9) unsigned default NULL,
  `finished` tinyint(1) default NULL,
  `startTaskDate` timestamp NOT NULL default CURRENT_TIMESTAMP,
  `finishTaskDate` timestamp NOT NULL default '0000-00-00 00:00:00',
  PRIMARY KEY  (`studentTaskId`,`taskId`,`objectId`),
  KEY `FK_STUDENT_TASK_OBJECTS` USING BTREE (`objectId`),
  KEY `FK_STUDENT_TASK_TASK` USING BTREE (`taskId`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

The problem I am having is with inserting a value in field startTaskDate. I've tried to do it like so:

void DBTaskProvider::saveTask(const ObjectID& objectID, const TaskGameStruct* const playerTask, const ActionType& actionType)
{
    try
        {
             time_t finishDate = playerTask->finishedDate;
             time_t startDate = playerTask->startDate;
           
             querySQL
      << "CALL GDB_INSERT_STUDENT_TASK("
      << playerTask->taskID << ","
      << playerTask->objectID << ","
      << playerTask->varOne << ","
      << playerTask->varTwo << ","
      << playerTask->finished << ", "
      << "'" << mysqlpp::escape << mysqlpp::DateTime(startDate) << "', "
      << "'" << mysqlpp::escape << mysqlpp::Date(finishYear, finishMonth, finishDay) << "')";
                  
      // Execute the insert statement.
      querySQL.use();
}

but I get the following error:

error LNK2019: unresolved external symbol "public: __thiscall mysqlpp::DateTime::DateTime(__int64)" (??0DateTime@mysqlpp@@QAE@_J@Z) referenced in function "public: void __thiscall Star::DBTaskProvider::saveTask(int const &,class Star::TaskGameStruct const * const,enum

Does anybody know what the problem is? Also, what is a good way to insert a value into a TIMESTAMP field using C++ and mysqlpp?Start Free Trial