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<CENTER><B><FONT SIZE=+2>ACE Tutorial 019</FONT></B></CENTER>
<CENTER><B><FONT SIZE=+2>Sharing your Memories</FONT></B></CENTER>
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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.
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<HR width=50%><P><center>shmem.h</center><HR width=50%>
<PRE>
<font color=red>// page05.html,v 1.7 2000/11/27 17:56:44 othman Exp</font>
<font color=blue>#ifndef</font> <font color=purple>SHMEM_H</font>
<font color=blue>#define</font> <font color=purple>SHMEM_H</font>
<font color=red>// This is where you'll find the ACE_Shared_Memory_SV object</font>
<font color=blue>#include</font> "<A HREF="../../../ace/Shared_Memory_SV.h">ace/Shared_Memory_SV.h</A>"
<font color=red>// SHMSZ is just enough for the alphabet and a null terminator</font>
<font color=blue>#define</font> <font color=purple>SHMSZ</font> 27
<font color=red>// Play with this, pick a value you like that isn't used by something else.</font>
<font color=blue>#define</font> <font color=purple>SHM_KEY</font> 4200
<font color=red>/*
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.
*/</font>
class SharedData
{
public:
<font color=red>// Construct the object and optionally initialize buf_.</font>
SharedData (int initialized = 1);
<font color=red>// Put some data into buf_</font>
void set (void);
<font color=red>// Show the data in buf_</font>
void show (void);
<font color=red>// What is the value of available_</font>
int available (void);
<font color=red>// Set the value of available_</font>
void available (int not_in_use);
protected:
<font color=red>// Big enough for a simple message</font>
char buf_[128];
<font color=red>// A cheap mutex</font>
int available_;
};
<font color=blue>#endif</font> <font color=red>/* SHMEM_H */</font>
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<HR width=50%><P><center>shmem.cpp</center><HR width=50%>
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<font color=red>// page05.html,v 1.7 2000/11/27 17:56:44 othman Exp</font>
<font color=blue>#include</font> "<font color=green>shmem.h</font>"
<font color=blue>#include</font> "<A HREF="../../../ace/Log_Msg.h">ace/Log_Msg.h</A>"
#if ! defined (ACE_LACKS_SYSV_SHMEM)
<font color=red>/*
Set the available_ flag to zero & optionally initialize the buf_
area.
*/</font>
<font color=#008888>SharedData::SharedData</font> (int initialize)
: available_ (0)
{
if (initialize)
<font color=#008888>ACE_OS::sprintf</font> (buf_, "<font color=green>UNSET\n</font>");
}
<font color=red>/*
Write the process ID into the buffer. This will prove to us that
the data really is shared between the client and server.
*/</font>
void <font color=#008888>SharedData::set</font> (void)
{
<font color=#008888>ACE_OS::sprintf</font> (buf_,
"<font color=green>My PID is (%d)\n</font>",
<font color=#008888>ACE_OS::getpid</font> ());
}
<font color=red>/*
Display the buffer to the user
*/</font>
void <font color=#008888>SharedData::show</font>(void)
{
ACE_DEBUG ((LM_INFO,
"<font color=green>(%P|%t) Shared Data text is (%s)\n</font>",
buf_));
}
<font color=red>// Show flag</font>
int <font color=#008888>SharedData::available</font>(void)
{
return available_;
}
<font color=red>// Set flag</font>
void <font color=#008888>SharedData::available</font>(int a)
{
available_ = a;
}
<font color=blue>#endif</font> <font color=red>/* ACE_LACKS_SYSV_SHMEM */</font>
</PRE>
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