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// $Id: Guards.cpp 91626 2010-09-07 10:59:20Z johnnyw $
#include "ace/config-lite.h"
#if defined (ACE_HAS_THREADS)
#include "ace/OS_main.h"
#include "ace/OS_Memory.h"
#include "ace/Guard_T.h"
#include "ace/Log_Msg.h"
#include "ace/Thread_Mutex.h"
// This file exists primarily to get code into the book to show different
// ways to do the same thing. For complete context and explanation, please
// see APG chapter 12.
class HA_Device_Repository {
public:
int update_device (int device_id);
private:
ACE_Thread_Mutex mutex_;
};
class Object {
};
static Object *object;
#if 0
// This is less-desired way to do this...
// Listing 1 code/ch12
int
HA_Device_Repository::update_device (int device_id)
{
this->mutex_.acquire ();
ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("(%t) Updating device %d\n"),
device_id));
// Allocate a new object.
ACE_NEW_RETURN (object, Object, -1);
// ...
// Use the object
this->mutex_.release ();
}
// Listing 1
// Listing 2 code/ch12
int
HA_Device_Repository::update_device (int device_id)
{
// Construct a guard specifying the type of the mutex as
// a template parameter and passing in the mutex to hold
// as a parameter.
// FUZZ: disable check_for_ACE_Guard
ACE_Guard<ACE_Thread_Mutex> guard (this->mutex_);
// FUZZ: enable check_for_ACE_Guard
// This can throw an exception that is not caught here.
ACE_NEW_RETURN (object, Object, -1);
// ..
// Use the object.
// ..
// Guard is destroyed, automatically releasing the lock.
}
// Listing 2
#endif /* 0 */
// Listing 3 code/ch12
int
HA_Device_Repository::update_device (int /* device_id */)
{
ACE_GUARD_RETURN (ACE_Thread_Mutex, mon, mutex_, -1);
ACE_NEW_RETURN (object, Object, -1);
// Use the object.
// ...
return 0;
}
// Listing 3
int ACE_TMAIN (int, ACE_TCHAR *[])
{
HA_Device_Repository rep;
rep.update_device (42);
return 0;
}
#else
#include "ace/OS_main.h"
#include "ace/OS_NS_stdio.h"
int ACE_TMAIN (int, ACE_TCHAR *[])
{
ACE_OS::puts (ACE_TEXT ("This example requires threads."));
return 0;
}
#endif /* ACE_HAS_THREADS */
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