ACE Tutorial 019
Sharing your Memories
Here's the mysterious shmem.h. I wanted to show it after the
placement-new client and server so that the SharedData object
would have some relevance.
shmem.h
// $Id: page05.html,v 1.4 1999/04/03 21:56:33 jcej Exp $
#ifndef SHMEM_H
#define SHMEM_H
// This is where you'll find the ACE_Shared_Memory_SV object
#include "ace/Shared_Memory_SV.h"
// SHMSZ is just enough for the alphabet and a null terminator
#define SHMSZ 27
// Play with this, pick a value you like that isn't used by something else.
#define SHM_KEY 4200
/*
This is what we stuff into shared memory via placement new in the
second client/server pair. Notice that it is a very basic object
with no virtual methods and only concrete data.
*/
class SharedData
{
public:
// Construct the object and optionally initialize buf_.
SharedData (int initialized = 1);
// Put some data into buf_
void set (void);
// Show the data in buf_
void show (void);
// What is the value of available_
int available (void);
// Set the value of available_
void available (int not_in_use);
protected:
// Big enough for a simple message
char buf_[128];
// A cheap mutex
int available_;
};
#endif /* SHMEM_H */
shmem.cpp
// $Id: page05.html,v 1.4 1999/04/03 21:56:33 jcej Exp $
#include "shmem.h"
#if ! defined (ACE_LACKS_SYSV_SHMEM)
/*
Set the available_ flag to zero & optionally initialize the buf_
area.
*/
SharedData::SharedData (int initialize)
: available_ (0)
{
if (initialize)
ACE_OS::sprintf (buf_, "UNSET\n");
}
/*
Write the process ID into the buffer. This will prove to us that
the data really is shared between the client and server.
*/
void SharedData::set (void)
{
ACE_OS::sprintf (buf_,
"My PID is (%d)\n",
ACE_OS::getpid ());
}
/*
Display the buffer to the user
*/
void SharedData::show(void)
{
ACE_DEBUG ((LM_INFO,
"(%P|%t) Shared Data text is (%s)\n",
buf_));
}
// Show flag
int SharedData::available(void)
{
return available_;
}
// Set flag
void SharedData::available(int a)
{
available_ = a;
}
#endif /* ACE_LACKS_SYSV_SHMEM */
[Tutorial Index] [Continue This Tutorial]