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<font color="#0000ff">// Copyright (c) 1999-2002 David Muse</font>
<font color="#0000ff">// See the COPYING file for more information.</font>
<font color="#a020f0">#ifndef RUDIMENTS_SHAREDMEMORY_H</font>
<font color="#a020f0">#define RUDIMENTS_SHAREDMEMORY_H</font>
<font color="#a020f0">#include </font><font color="#ff00ff"><rudiments/private/sharedmemoryincludes.h></font>
<font color="#0000ff">// Shared memory segments allow multiple processes to access a common</font>
<font color="#0000ff">// address space.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// Shared memory can be used for interprocess communication and is generally</font>
<font color="#0000ff">// faster than using fifo's or unix sockets.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// To synchronize access to shared memory, use the semaphoreset class.</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// A shared memory segment is owned by a user and group and has access </font>
<font color="#0000ff">// permissions just like a file.</font>
<font color="#a020f0">#ifdef RUDIMENTS_NAMESPACE</font>
<font color="#2e8b57"><b>namespace</b></font> rudiments {
<font color="#a020f0">#endif</font>
<font color="#2e8b57"><b>class</b></font> sharedmemoryprivate;
<font color="#2e8b57"><b>class</b></font> sharedmemory {
<font color="#a52a2a"><b>public</b></font>:
sharedmemory();
<font color="#0000ff">// Creates a shared memory segment.</font>
~sharedmemory();
<font color="#0000ff">// Cleans up and removes the shared memory segment if</font>
<font color="#0000ff">// it was created by the create() or createOrAttach() </font>
<font color="#0000ff">// method below. If it was just attached to, it is</font>
<font color="#0000ff">// not removed.</font>
<font color="#2e8b57"><b>bool</b></font> create(key_t key, <font color="#2e8b57"><b>size_t</b></font> size,
mode_t permissions);
<font color="#0000ff">// Creates a shared memory segment of "size" bytes, </font>
<font color="#0000ff">// identified by "key".</font>
<font color="#0000ff">// "key" should be generated using the ftok</font>
<font color="#0000ff">// function.</font>
<font color="#0000ff">// "permissions" sets the access permissions</font>
<font color="#0000ff">// for the segment.</font>
<font color="#2e8b57"><b>bool</b></font> attach(key_t key);
<font color="#0000ff">// Attaches to a shared memory identified by "key".</font>
<font color="#2e8b57"><b>bool</b></font> createOrAttach(key_t key, <font color="#2e8b57"><b>size_t</b></font> size,
mode_t permissions);
<font color="#0000ff">// Attempts to create the shared memory segment </font>
<font color="#0000ff">// identified by "key". If this fails, it attempts</font>
<font color="#0000ff">// to attach to a shared memory segment identified by</font>
<font color="#0000ff">// "key".</font>
<font color="#2e8b57"><b>void</b></font> dontRemove();
<font color="#0000ff">// Instructs the destructor not to remove the shared</font>
<font color="#0000ff">// memory segment if it was created during a call to</font>
<font color="#0000ff">// create() or createOrAttach() above. This is useful</font>
<font color="#0000ff">// if an application creates a shared memory segment</font>
<font color="#0000ff">// then forks and wants to delete the shared memory</font>
<font color="#0000ff">// segment in the forked process but does not want</font>
<font color="#0000ff">// the segment removed from the system.</font>
<font color="#2e8b57"><b>bool</b></font> forceRemove();
<font color="#0000ff">// Removes the shared memory segment whether it was</font>
<font color="#0000ff">// created or just attached to.</font>
<font color="#2e8b57"><b>int</b></font> getId() <font color="#2e8b57"><b>const</b></font>;
<font color="#0000ff">// Returns the internal id for the </font>
<font color="#0000ff">// shared memory segment.</font>
<font color="#2e8b57"><b>void</b></font> *getPointer() <font color="#2e8b57"><b>const</b></font>;
<font color="#0000ff">// Returns a pointer to the shared memory</font>
<font color="#0000ff">// segment. Data may be read from or written</font>
<font color="#0000ff">// to the segment using this pointer.</font>
<font color="#2e8b57"><b>bool</b></font> setUserName(<font color="#2e8b57"><b>const</b></font> <font color="#2e8b57"><b>char</b></font> *username);
<font color="#0000ff">// Makes this shared memory segment owned by</font>
<font color="#0000ff">// the user "username".</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// Note that setUserName() uses the passwdentry class.</font>
<font color="#0000ff">// If you are using this method in a multithreaded</font>
<font color="#0000ff">// application, you may need to supply the passwdentry</font>
<font color="#0000ff">// class a mutex. See passwdentry.h for more detail.</font>
<font color="#2e8b57"><b>bool</b></font> setGroupName(<font color="#2e8b57"><b>const</b></font> <font color="#2e8b57"><b>char</b></font> *groupname);
<font color="#0000ff">// Makes this shared memory segment owned by</font>
<font color="#0000ff">// the group "groupname".</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// Note that setGroupName() uses the groupentry class.</font>
<font color="#0000ff">// If you are using this method in a multithreaded</font>
<font color="#0000ff">// application, you may need to supply the groupentry</font>
<font color="#0000ff">// class a mutex. See groupentry.h for more detail.</font>
<font color="#2e8b57"><b>bool</b></font> setUserId(uid_t uid);
<font color="#0000ff">// makes this shared memory segment owned by</font>
<font color="#0000ff">// the user identified by uid</font>
<font color="#2e8b57"><b>bool</b></font> setGroupId(gid_t gid);
<font color="#0000ff">// makes this shared memory segment owned by</font>
<font color="#0000ff">// the group identified by gid</font>
<font color="#2e8b57"><b>bool</b></font> setPermissions(mode_t permissions);
<font color="#0000ff">// sets the access permissions for this</font>
<font color="#0000ff">// shared memory segment to "permissions"</font>
<font color="#2e8b57"><b>const</b></font> <font color="#2e8b57"><b>char</b></font> *getUserName();
<font color="#0000ff">// returns the name of the user that owns this</font>
<font color="#0000ff">// shared memory segment</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// Note that getUserName() uses the passwdentry class.</font>
<font color="#0000ff">// If you are using this method in a multithreaded</font>
<font color="#0000ff">// application, you may need to supply the passwdentry</font>
<font color="#0000ff">// class a mutex. See passwdentry.h for more detail.</font>
<font color="#2e8b57"><b>const</b></font> <font color="#2e8b57"><b>char</b></font> *getGroupName();
<font color="#0000ff">// returns the name of the group that owns this</font>
<font color="#0000ff">// shared memory segment</font>
<font color="#0000ff">//</font>
<font color="#0000ff">// Note that getGroupName() uses the groupentry class.</font>
<font color="#0000ff">// If you are using this method in a multithreaded</font>
<font color="#0000ff">// application, you may need to supply the groupentry</font>
<font color="#0000ff">// class a mutex. See groupentry.h for more detail.</font>
uid_t getUserId();
<font color="#0000ff">// returns the user id of the user that owns this</font>
<font color="#0000ff">// shared memory segment</font>
gid_t getGroupId();
<font color="#0000ff">// returns the group id of the group that owns this</font>
<font color="#0000ff">// shared memory segment</font>
mode_t getPermissions();
<font color="#0000ff">// returns the access permissions for this</font>
<font color="#0000ff">// shared memory segment</font>
<font color="#a020f0"> #include </font><font color="#ff00ff"><rudiments/private/sharedmemory.h></font>
};
<font color="#a020f0">#ifdef RUDIMENTS_NAMESPACE</font>
}
<font color="#a020f0">#endif</font>
<font color="#a020f0">#endif</font>
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