Our Task object executes in one or more threads and reads from the message queue it contains.
#include "ace/Task.h"
/*
Like the thread-pool server tutorial, we'll derive from ACE_Task<>.
Our goal here is to show off the ACE_Message_Queue and the best way
to do that is to use one to pass data between threads. The easiest
way to create threads is with ACE_Task<>
*/
class Task : public ACE_Task < ACE_MT_SYNCH >
{
public:
typedef ACE_Task < ACE_MT_SYNCH > inherited;
/*
The constructor/destructor are simple but take care of some
necessary housekeeping.
*/
Task (void);
~Task (void);
/*
To make our Task<> derivative look more like other ACE objects
I've added an open() method. It will take care of activate()ing
the object.
*/
int open (int threads = 1);
/*
Our worker method
*/
int svc (void);
/*
All we'll do here is print a message to the user.
*/
int close (u_long flags = 0);
protected:
/*
Just to be clever, I'll use an ACE_Barrier to cause the threads
to sync in svc() before doing any real work.
*/
ACE_Barrier *barrier_;
};
The only thing here that we didn't see in the thread-pool server is the ACE_Barrier. The application logic really doesn't need it but it is a handy way to synchronize the threads at the beginning of svc(). In testing I found that if I didn't sync svc(), the first thread to get activated would tend to get all of the messages before the other threads came alive.