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diff --git a/ACE/ace/RW_Process_Mutex.h b/ACE/ace/RW_Process_Mutex.h
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+++ b/ACE/ace/RW_Process_Mutex.h
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+// -*- C++ -*-
+//
+//=============================================================================
+/**
+ *  @file    RW_Process_Mutex.h
+ *
+ *  $Id$
+ *
+ *  @author Douglas C. Schmidt <schmidt@cs.wustl.edu>
+ */
+//=============================================================================
+
+#ifndef ACE_RW_PROCESS_MUTEX_H
+#define ACE_RW_PROCESS_MUTEX_H
+
+#include /**/ "ace/pre.h"
+
+#include "ace/File_Lock.h"
+
+#if !defined (ACE_LACKS_PRAGMA_ONCE)
+# pragma once
+#endif /* ACE_LACKS_PRAGMA_ONCE */
+
+#include "ace/Default_Constants.h"
+#include "ace/OS_NS_fcntl.h"
+
+ACE_BEGIN_VERSIONED_NAMESPACE_DECL
+
+/**
+ * @class ACE_RW_Process_Mutex
+ *
+ * @brief Wrapper for readers/writer locks that exist across processes.
+ *
+ * Note that because this class uses the
+ * <ACE_File_Lock> as its implementation it only can be reliably
+ * used between separate processes, rather than threads in the
+ * same process.  This isn't a limitation of ACE, it's simply
+ * the file lock semantics on UNIX and Win32.
+ * \todo For systems with pthread_rwlockattr_setpshared one
+ * may consider using them to make the mutex faster.
+ */
+class ACE_Export ACE_RW_Process_Mutex
+{
+public:
+  /// Create a readers/writer <Process_Mutex>, passing in the optional
+  /// <name>, <flags> and <mode> \sa ACE_File_Lock.
+  ///  If not specified, a name is generated and flags and mode are set
+  ///  to default platform values.
+#if defined (ACE_WIN32)
+  ACE_RW_Process_Mutex (const ACE_TCHAR *name = 0,
+                        int flags = O_CREAT|O_RDWR,
+                        mode_t mode =  ACE_DEFAULT_OPEN_PERMS);
+#else
+  ACE_RW_Process_Mutex (const ACE_TCHAR *name = 0,
+                        int flags = O_CREAT|O_RDWR,
+                            mode_t mode = S_IRUSR | S_IWUSR );
+#endif /* ACE_WIN32 */
+
+  ~ACE_RW_Process_Mutex (void);
+
+  /**
+   * Explicitly destroy the mutex.  Note that only one thread should
+   * call this method since it doesn't protect against race
+   * conditions.
+   */
+  int remove (void);
+
+  /// Acquire lock ownership (wait on queue if necessary).
+  int acquire (void);
+
+  /**
+   * Conditionally acquire lock (i.e., don't wait on queue).  Returns
+   * -1 on failure.  If we "failed" because someone else already had
+   * the lock, <errno> is set to <EBUSY>.
+   */
+  int tryacquire (void);
+
+  /// Release lock and unblock a thread at head of queue.
+  int release (void);
+
+  /// Acquire lock ownership (wait on queue if necessary).
+  int acquire_read (void);
+
+  /// Acquire lock ownership (wait on queue if necessary).
+  int acquire_write (void);
+
+  /**
+   * Conditionally acquire a lock (i.e., won't block).  Returns -1 on
+   * failure.  If we "failed" because someone else already had the
+   * lock, <errno> is set to <EBUSY>.
+   */
+  int tryacquire_read (void);
+
+  /**
+   * Conditionally acquire a lock (i.e., won't block).  Returns -1 on
+   * failure.  If we "failed" because someone else already had the
+   * lock, <errno> is set to <EBUSY>.
+   */
+  int tryacquire_write (void);
+
+  /// Attempt to upgrade a read lock to a write lock. Returns 0 on
+  /// success, -1 on failure.
+  int tryacquire_write_upgrade (void);
+
+  /// Return the underlying lock.
+  const ACE_File_Lock &lock (void) const;
+
+  /// Dump the state of an object.
+  void dump (void) const;
+
+  /// Declare the dynamic allocation hooks.
+  ACE_ALLOC_HOOK_DECLARE;
+
+private:
+  /// If the user does not provide a name we generate a unique name in
+  /// this buffer.
+  ACE_TCHAR name_[ACE_UNIQUE_NAME_LEN];
+
+  /// Create and return the unique name.
+  const ACE_TCHAR *unique_name (void);
+
+  /// We need this to get the readers/writer semantics...
+  ACE_File_Lock lock_;
+};
+
+ACE_END_VERSIONED_NAMESPACE_DECL
+
+#if defined (__ACE_INLINE__)
+#include "ace/RW_Process_Mutex.inl"
+#endif /* __ACE_INLINE__ */
+
+#include /**/ "ace/post.h"
+#endif /* ACE_RW_PROCESS_MUTEX_H */