path: root/ace/Thread_Manager.h

/* -*- C++ -*- */
// $Id$

// ============================================================================
//
// = LIBRARY
//    ace
//
// = FILENAME
//    Thread_Manager.h
//
// = AUTHOR
//    Doug Schmidt
//
// ============================================================================

#ifndef ACE_THREAD_MANAGER_H
#define ACE_THREAD_MANAGER_H

#include "ace/Thread.h"

#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

#include "ace/Synch.h"
#include "ace/Containers.h"
#include "ace/Free_List.h"

// The following macros control how a Thread Manager manages a pool of
// Thread_Descriptor.  Currently, the default behavior is not to
// preallocate any thread descriptor and never (well, almost never)
// free up any thread descriptor until the Thread Manager gets
// destructed.  Which means, once your system is stable, you rarely
// need to pay the price of memory allocation.  On a deterministic
// system, which means, the number of threads spawned can be
// determined before hand, you can either redefine the memory pool
// size macros to suit your need or constructed the Thread_Manager
// accordingly.  That way, you don't pay the price of memory
// allocation when the system is really doing its job.  OTOH, on
// system with resources constraint, you may want to lower the size of
// ACE_DEFAULT_THREAD_MANAGER_HWM to avoid unused memory hanging
// around.

#if !defined (ACE_DEFAULT_THREAD_MANAGER_PREALLOC)
# define ACE_DEFAULT_THREAD_MANAGER_PREALLOC 0
#endif /* ACE_DEFAULT_THREAD_MANAGER_PREALLOC */

#if !defined (ACE_DEFAULT_THREAD_MANAGER_LWM)
# define ACE_DEFAULT_THREAD_MANAGER_LWM 1
#endif /* ACE_DEFAULT_THREAD_MANAGER_LWM */

#if !defined (ACE_DEFAULT_THREAD_MANAGER_INC)
# define ACE_DEFAULT_THREAD_MANAGER_INC 1
#endif /* ACE_DEFAULT_THREAD_MANAGER_INC */

#if !defined (ACE_DEFAULT_THREAD_MANAGER_HWM)
# define ACE_DEFAULT_THREAD_MANAGER_HWM ACE_DEFAULT_FREE_LIST_HWM
// this is a big number
#endif /* ACE_DEFAULT_THREAD_MANAGER_HWM */

// This is the synchronization mechanism used to prevent a thread
// descriptor gets removed from the Thread_Manager before it gets
// stash into it.  If you want to disable this feature (and risk of
// corrupting the freelist,) you define the lock as ACE_Null_Mutex.
// Usually, if you can be sure that your threads will run for an
// extended period of time, you can safely disable the lock.

#if !defined (ACE_DEFAULT_THREAD_MANAGER_LOCK)
# define ACE_DEFAULT_THREAD_MANAGER_LOCK ACE_SYNCH_MUTEX
#endif /* ACE_DEFAULT_THREAD_MANAGER_LOCK */

// Forward declarations.
class ACE_Task_Base;
class ACE_Thread_Manager;
class ACE_Thread_Descriptor;

#if !defined(ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
class ACE_Export ACE_At_Thread_Exit
{
  // = TITLE
  // Contains a method to be applied when a thread is terminated.
  friend class ACE_Thread_Descriptor;
  friend class ACE_Thread_Manager;
public:
  // Default constructor
  ACE_At_Thread_Exit(void);

  // The destructor
  virtual ~ACE_At_Thread_Exit(void);

  // At_Thread_Exit has the ownership?
  int is_owner() const;

  // Set the ownership of the At_Thread_Exit
  int is_owner(int owner);

  // This At_Thread_Exit was applied?
  int was_applied() const;

  // Set applied state of At_Thread_Exit
  int was_applied(int applied);

protected:
  ACE_At_Thread_Exit* next_;
  // The next At_Thread_Exit hook in the list.

  // Do the apply if necessary
  void do_apply();

  virtual void apply() = 0;
  // The apply method.

  ACE_Thread_Descriptor* td_;
  // The Thread_Descriptor where this at is registered.

  int was_applied_;
  // The at was applied?

  int is_owner_;
  // The at has the ownership of this?
};

class ACE_Export ACE_At_Thread_Exit_Func : public ACE_At_Thread_Exit
{
public:
   // Constructor
   ACE_At_Thread_Exit_Func(void* object,
                           ACE_CLEANUP_FUNC func,
                           void* param = 0);

  virtual ~ACE_At_Thread_Exit_Func (void);

protected:
   void* object_;
   // The object to be cleanup

   ACE_CLEANUP_FUNC func_;
   // The cleanup func

   void* param_;
   // A param if required

   // The apply method
   void apply();
};

#endif /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */

class ACE_Thread_Descriptor_Base : public ACE_OS_Thread_Descriptor
{
  // = TITLE
  //     Basic information for thread descriptors.  These information
  //     gets extracted out because we need it after a thread is
  //     terminated.

  friend class ACE_Thread_Manager;
  friend class ACE_Double_Linked_List<ACE_Thread_Descriptor_Base>;
  friend class ACE_Double_Linked_List_Iterator<ACE_Thread_Descriptor_Base>;
  friend class ACE_Double_Linked_List<ACE_Thread_Descriptor>;
  friend class ACE_Double_Linked_List_Iterator<ACE_Thread_Descriptor>;
public:
  ACE_Thread_Descriptor_Base (void);
  ~ACE_Thread_Descriptor_Base (void);

  // = We need the following operators to make Borland happy.

  int operator== (const ACE_Thread_Descriptor_Base &rhs) const;
  // Equality operator.

  int operator!= (const ACE_Thread_Descriptor_Base &rhs) const;
  // Inequality operator.

  int grp_id (void);
  // Group ID.

  ACE_UINT32 state (void);
  // Current state of the thread.

  ACE_Task_Base *task (void);
  // Return the pointer to an <ACE_Task_Base> or NULL if there's no
  // <ACE_Task_Base> associated with this thread.;

protected:
  ACE_thread_t thr_id_;
  // Unique thread ID.

  ACE_hthread_t thr_handle_;
  // Unique handle to thread (used by Win32 and AIX).

  int grp_id_;
  // Group ID.

  ACE_UINT32 thr_state_;
  // Current state of the thread.

  ACE_Task_Base *task_;
  // Pointer to an <ACE_Task_Base> or NULL if there's no
  // <ACE_Task_Base>.

  ACE_Thread_Descriptor_Base *next_;
  ACE_Thread_Descriptor_Base *prev_;
  // We need these pointers to maintain the double-linked list in a
  // thread managers.
};

class ACE_Export ACE_Thread_Descriptor : public ACE_Thread_Descriptor_Base
{
  // = TITLE
  //   Information for controlling threads that run under the control
  //   of the <Thread_Manager>.
#if !defined(ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
  friend class ACE_At_Thread_Exit;
#endif /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */
  friend class ACE_Thread_Manager;
  friend class ACE_Double_Linked_List<ACE_Thread_Descriptor>;
  friend class ACE_Double_Linked_List_Iterator<ACE_Thread_Descriptor>;
public:
  // = Initialization method.
  ACE_Thread_Descriptor (void);

  // = Accessor methods.
  ACE_thread_t self (void);
  // Unique thread id.

  void self (ACE_hthread_t &);
  // Unique handle to thread (used by Win32 and AIX).

  void dump (void) const;
  // Dump the state of an object.

#if !defined(ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
  void log_msg_cleanup(ACE_Log_Msg* log_msg);
  // This cleanup function must be called only for ACE_TSS_cleanup.
  // The ACE_TSS_cleanup delegate Log_Msg instance destruction when
  // Log_Msg cleanup is called before terminate.

  int at_exit (ACE_At_Thread_Exit* cleanup);
  // Register an At_Thread_Exit hook and the ownership is acquire by
  // Thread_Descriptor, this is the usual case when the AT is dynamically
  // allocated.

  int at_exit (ACE_At_Thread_Exit& cleanup);
  // Register an At_Thread_Exit hook and the ownership is retained for the
  // caller. Normally used when the at_exit hook is created in stack.
#endif /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */

  int at_exit (void *object,
               ACE_CLEANUP_FUNC cleanup_hook,
               void *param);
  // Register an object (or array) for cleanup at thread termination.
  // "cleanup_hook" points to a (global, or static member) function
  // that is called for the object or array when it to be destroyed.
  // It may perform any necessary cleanup specific for that object or
  // its class.  "param" is passed as the second parameter to the
  // "cleanup_hook" function; the first parameter is the object (or
  // array) to be destroyed.  Returns 0 on success, non-zero on
  // failure: -1 if virtual memory is exhausted or 1 if the object (or
  // arrayt) had already been registered.

  ~ACE_Thread_Descriptor (void);
  // Do nothing destructor to keep some compilers happy

  void acquire_release (void);
  // Do nothing but to acquire the thread descriptor's lock and
  // release.  This will first check if the thread is registered or
  // not.  If it is already registered, there's no need to reacquire
  // the lock again.  This is used mainly to get newly spawned thread
  // in synch with thread manager and prevent it from accessing its
  // thread descriptor before it gets fully built.  This function is
  // only called from ACE_Log_Msg::thr_desc.

  ACE_INLINE_FOR_GNUC void set_next (ACE_Thread_Descriptor *td);
  ACE_INLINE_FOR_GNUC ACE_Thread_Descriptor *get_next (void);
  // Set/get the <next_> pointer.  These are required by the
  // ACE_Free_List.  ACE_INLINE is specified here because one version
  // of g++ couldn't grok this code without it.

private:
#if !defined (ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
  void at_pop (int apply = 1);
  // Pop an At_Thread_Exit from at thread termination list, apply the at
  // if apply is true.

  void at_push (ACE_At_Thread_Exit* cleanup,
                int is_owner = 0);
  // Push an At_Thread_Exit to at thread termination list and set the
  // ownership of at.

  void do_at_exit (void);
  // Run the AT_Thread_Exit hooks.

  void terminate (void);
  // terminate realize the cleanup process to thread termination

  ACE_Log_Msg *log_msg_;
  // Thread_Descriptor is the ownership of ACE_Log_Msg if log_msg_!=0
  // This can occur because ACE_TSS_cleanup was executed before terminate.

  ACE_At_Thread_Exit *at_exit_list_;
  // The AT_Thread_Exit list
#endif  /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */

  ACE_Cleanup_Info cleanup_info_;
  // Stores the cleanup info for a thread.
  // @@ Note, this should be generalized to be a stack of
  // <ACE_Cleanup_Info>s.

#if !defined(ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
  ACE_Thread_Manager* tm_;
  // Pointer to an <ACE_Thread_Manager> or NULL if there's no
  // <ACE_Thread_Manager>.
#endif /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */

  ACE_DEFAULT_THREAD_MANAGER_LOCK *sync_;
  // Registration lock to prevent premature removal of thread descriptor.

#if !defined(ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
  int terminated_;
  // Keep track of termination status.
#endif  /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */
};

// Forward declaration.
class ACE_Thread_Control;

// This typedef should be (and used to be) inside the
// ACE_Thread_Manager declaration.  But, it caused compilation
// problems on g++/VxWorks/i960 with -g.  Note that
// ACE_Thread_Manager::THR_FUNC is only used internally in
// ACE_Thread_Manager, so it's not useful for anyone else.
// It also caused problems on IRIX5 with g++.
#if defined (__GNUG__)
typedef int (ACE_Thread_Manager::*ACE_THR_MEMBER_FUNC)(ACE_Thread_Descriptor *, int);
#endif /* __GNUG__ */

class ACE_Export ACE_Thread_Manager
{
  // = TITLE
  //    Manages a pool of threads.
  //
  // = DESCRIPTION
  //    This class allows operations on groups of threads atomically.
  //    The default behavior of thread manager is to wait on
  //    all threads under it's management when it gets destructed.
  //    Therefore, remember to remove a thread from thread manager if
  //    you don't want it to wait for the thread. There are also
  //    function to disable this default wait-on-exit behavior.
  //    However, if your program depends on turning this off to run
  //    correctly, you are probably doing something wrong.  Rule of
  //    thumb, use ACE_Thread to manage your daemon threads.
  //
  //    Notice that if there're threads live beyond the scope of main (),
  //    you are sure to have resource leaks in your program.  Remember
  //    to wait on threads before exiting main() if that could happen
  //    in your programs.
public:
  friend class ACE_Thread_Control;
#if !defined(ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
  friend class ACE_Thread_Descriptor;
#endif /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */

#if !defined (__GNUG__)
  typedef int (ACE_Thread_Manager::*ACE_THR_MEMBER_FUNC)(ACE_Thread_Descriptor *, int);
#endif /* !__GNUG__ */

  // These are the various states a thread managed by the
  // <Thread_Manager> can be in.
  enum
  {
    ACE_THR_IDLE = 0x00000000,
    // Uninitialized.

    ACE_THR_SPAWNED = 0x00000001,
    // Created but not yet running.

    ACE_THR_RUNNING = 0x00000002,
    // Thread is active (naturally, we don't know if it's actually
    // *running* because we aren't the scheduler...).

    ACE_THR_SUSPENDED = 0x00000004,
    // Thread is suspended.

    ACE_THR_CANCELLED = 0x00000008,
    // Thread has been cancelled (which is an indiction that it needs to
    // terminate...).

    ACE_THR_TERMINATED = 0x00000010,
    // Thread has shutdown, but the slot in the thread manager hasn't
    // been reclaimed yet.

    ACE_THR_JOINING = 0x10000000
    // Join operation has been invoked on the thread by thread manager.
  };

  // = Initialization and termination methods.
  ACE_Thread_Manager (size_t preaolloc = 0,
                      size_t lwm = ACE_DEFAULT_THREAD_MANAGER_LWM,
                      size_t inc = ACE_DEFAULT_THREAD_MANAGER_INC,
                      size_t hwm = ACE_DEFAULT_THREAD_MANAGER_HWM);
  virtual ~ACE_Thread_Manager (void);

  static ACE_Thread_Manager *instance (void);
  // Get pointer to a process-wide <ACE_Thread_Manager>.

  static ACE_Thread_Manager *instance (ACE_Thread_Manager *);
  // Set pointer to a process-wide <ACE_Thread_Manager> and return
  // existing pointer.

  static void close_singleton (void);
  // Delete the dynamically allocated Singleton

  int open (size_t size = 0);
  // No-op.  Currently unused.

  int close ();
  // Release all resources.
  // By default, this method will wait till all threads
  // exit.  However, when called from <close_singleton>, most global resources
  // are destroyed and thus, we don't try to wait but just clean up the thread
  // descriptor list.

  // The ACE_thread_t * argument to each of the spawn () family member
  // functions is interpreted and used as shown in the following
  // table.  NOTE:  the final option, to provide task names, is _only_
  // supported on VxWorks!
  //
  // Value of ACE_thread_t * argument  Use                         Platforms
  // ================================  ==========================  =========
  // 0                                 Not used.                   All
  // non-0 (and points to 0 char *     The task name is passed     All
  //   on VxWorks)                       back in the char *.
  // non-0, points to non-0 char *     The char * is used as       VxWorks only
  //                                     the task name.  The
  //                                     argument is not modified.

  int spawn (ACE_THR_FUNC func,
             void *args = 0,
             long flags = THR_NEW_LWP | THR_JOINABLE,
             ACE_thread_t * = 0,
             ACE_hthread_t *t_handle = 0,
             long priority = ACE_DEFAULT_THREAD_PRIORITY,
             int grp_id = -1,
             void *stack = 0,
             size_t stack_size = 0);
  // Create a new thread, which executes <func>.
  // Returns: on success a unique group id that can be used to control
  // other threads added to the same group.  On failure, returns -1.

  int spawn_n (size_t n,
               ACE_THR_FUNC func,
               void *args = 0,
               long flags = THR_NEW_LWP | THR_JOINABLE,
               long priority = ACE_DEFAULT_THREAD_PRIORITY,
               int grp_id = -1,
               ACE_Task_Base *task = 0,
               ACE_hthread_t thread_handles[] = 0,
               void *stack[] = 0,
               size_t stack_size[] = 0);
  // Create N new threads, all of which execute <func>.
  // Returns: on success a unique group id that can be used to control
  // all of the threads in the same group.  On failure, returns -1.

  int spawn_n (ACE_thread_t thread_ids[],
               size_t n,
               ACE_THR_FUNC func,
               void *args,
               long flags,
               long priority = ACE_DEFAULT_THREAD_PRIORITY,
               int grp_id = -1,
               void *stack[] = 0,
               size_t stack_size[] = 0,
               ACE_hthread_t thread_handles[] = 0);
  // Spawn N new threads, which execute <func> with argument <arg>.
  // If <thread_ids> != 0 the thread_ids of successfully spawned
  // threads will be placed into the <thread_ids> buffer (which must
  // be the same size as <n>).  If <stack> != 0 it is assumed to be an
  // array of <n> pointers to the base of the stacks to use for the
  // threads being spawned.  If <stack_size> != 0 it is assumed to be
  // an array of <n> values indicating how big each of the
  // corresponding <stack>s are.  If <thread_handles> != 0 it is
  // assumed to be an array of <n> thread_handles that will be
  // assigned the values of the thread handles being spawned.  Returns
  // -1 on failure (<errno> will explain...), otherwise returns the
  // group id of the threads.

  void *exit (void *status,
              int do_thread_exit = 1);
  // Called to clean up when a thread exits.  If <do_thread_exit> is
  // non-0 then <ACE_Thread::exit> is called to exit the thread, in
  // which case <status> is passed as the exit value of the thread.
  // Should _not_ be called by main thread.

  int wait (const ACE_Time_Value *timeout = 0,
            int abandon_detached_threads = 0);
  // Block until there are no more threads running in the
  // <Thread_Manager> or <timeout> expires.  Note that <timeout> is
  // treated as "absolute" time.  Returns 0 on success and -1 on
  // failure.  If <abandon_detached_threads> is set, wait will first
  // check thru its thread list for threads with THR_DETACHED or
  // THR_DAEMON flags set and remove these threads.  Notice that
  // unlike other wait_* function, by default, wait () does wait on
  // all thread spawned by this thread_manager no matter the detached
  // flags are set or not unless it is called with
  // <abandon_detached_threads> flag set.

  int join (ACE_thread_t tid, void **status = 0);
  // Join a thread specified by <tid>.  Do not wait on a detached thread.

  int wait_grp (int grp_id);
  // Block until there are no more threads running in a group.
  // Returns 0 on success and -1 on failure.  Notice that wait_grp
  // will not wait on detached threads.

  // = Accessors for ACE_Thread_Descriptors.
  ACE_Thread_Descriptor *thread_desc_self (void);
  // Get a pointer to the calling thread's own thread_descriptor.
  // This must be called from a spawn thread.  This function will
  // fetch the info from TSS.

  ACE_Thread_Descriptor *thread_descriptor (ACE_thread_t);
  // Return a pointer to the thread's Thread_Descriptor,
  // 0 if fail.

  ACE_Thread_Descriptor *hthread_descriptor (ACE_hthread_t);
  // Return a pointer to the thread's Thread_Descriptor,
  // 0 if fail.

  int thr_self (ACE_hthread_t &);
  // Return the "real" handle to the calling thread, caching it if
  // necessary in TSS to speed up subsequent lookups. This is
  // necessary since on some platforms (e.g., Win32) we can't get this
  // handle via direct method calls.  Notice that you should *not*
  // close the handle passed back from this method.  It is used
  // internally by Thread Manager.  On the other hand, you *have to*
  // use this internal thread handle when working on Thread_Manager.
  // Return -1 if fail.

  ACE_thread_t thr_self (void);
  // Return the unique ID of the thread.  This is not strictly
  // necessary (because a thread can always just call
  // <ACE_Thread::self>).  However, we put it here to be complete.

  ACE_Task_Base *task (void);
  // Returns a pointer to the current <ACE_Task_Base> we're executing
  // in if this thread is indeed running in an <ACE_Task_Base>, else
  // return 0.

  // = Suspend methods, which isn't supported on POSIX pthreads (will not block).
  int suspend_all (void);
  // Suspend all threads
  int suspend (ACE_thread_t);
  // Suspend a single thread.
  int suspend_grp (int grp_id);
  // Suspend a group of threads.
  int testsuspend (ACE_thread_t t_id);
  // True if <t_id> is inactive (i.e., suspended), else false.

  // = Resume methods, which isn't supported on POSIX pthreads (will not block).
  int resume_all (void);
  // Resume all stopped threads
  int resume (ACE_thread_t);
  // Resume a single thread.
  int resume_grp (int grp_id);
  // Resume a group of threads.
  int testresume (ACE_thread_t t_id);
  // True if <t_id> is active (i.e., resumed), else false.

  // = Kill methods, send signals -- which isn't supported on Win32 (will not block).
  int kill_all (int signum);
  // Send signum to all stopped threads
  int kill (ACE_thread_t,
            int signum);
  // Kill a single thread.
  int kill_grp (int grp_id,
                int signum);
  // Kill a group of threads.

  // = Cancel methods, which provides a cooperative thread-termination mechanism (will not block).
  int cancel_all (int async_cancel = 0);
  // Cancel's all the threads.
  int cancel (ACE_thread_t, int async_cancel = 0);
  // Cancel a single thread.
  int cancel_grp (int grp_id, int async_cancel = 0);
  // Cancel a group of threads.
  int testcancel (ACE_thread_t t_id);
  // True if <t_id> is cancelled, else false.

  // = Set/get group ids for a particular thread id.
  int set_grp (ACE_thread_t,
               int grp_id);
  int get_grp (ACE_thread_t,
               int &grp_id);

  // = The following methods are new methods which resemble current
  // methods in <ACE_Thread Manager>. For example, the <apply_task>
  // method resembles the <apply_thr> method, and <suspend_task>
  // resembles <suspend_thr>.

  // = Operations on ACE_Tasks.
  int wait_task (ACE_Task_Base *task);
  // Block until there are no more threads running in <task>.  Returns
  // 0 on success and -1 on failure.  Notice that wait_task will not
  // wait on detached threads.
  int suspend_task (ACE_Task_Base *task);
  // Suspend all threads in an ACE_Task.
  int resume_task (ACE_Task_Base *task);
  // Resume all threads in an ACE_Task.
  int kill_task (ACE_Task_Base *task,
                 int signum);
  // Send a signal <signum> to all threads in an <ACE_Task>.

  int cancel_task (ACE_Task_Base *task, int async_cancel = 0);
  // Cancel all threads in an <ACE_Task>.  If <async_cancel> is non-0,
  // then asynchronously cancel these threads if the OS platform
  // supports cancellation.  Otherwise, perform a "cooperative"
  // cancellation.

  // = Collect thread handles in the thread manager.  Notice that
  //   the collected information is just a snapshot.
  int hthread_within (ACE_hthread_t handle);
  int thread_within (ACE_thread_t tid);
  // Check if the thread is managed by the thread manager.  Return true if
  // the thread is found, false otherwise.

  int num_tasks_in_group (int grp_id);
  // Returns the number of <ACE_Task_Base> in a group.

  int num_threads_in_task (ACE_Task_Base *task);
  // Returns the number of threads in an <ACE_Task_Base>.

  int task_list (int grp_id,
                 ACE_Task_Base *task_list[],
                 size_t n);
  // Returns in <task_list> a list of up to <n> <ACE_Tasks> in a
  // group.  The caller must allocate the memory for <task_list>.  In
  // case of an error, -1 is returned. If no requested values are
  // found, 0 is returned, otherwise correct number of retrieved
  // values are returned.

  int thread_list (ACE_Task_Base *task,
                   ACE_thread_t thread_list[],
                   size_t n);
  // Returns in <thread_list> a list of up to <n> thread ids in an
  // <ACE_Task_Base>.  The caller must allocate the memory for
  // <thread_list>.  In case of an error, -1 is returned. If no
  // requested values are found, 0 is returned, otherwise correct
  // number of retrieved values are returned.

  int hthread_list (ACE_Task_Base *task,
                    ACE_hthread_t hthread_list[],
                    size_t n);
  // Returns in <hthread_list> a list of up to <n> thread handles in
  // an <ACE_Task_Base>.  The caller must allocate memory for
  // <hthread_list>.  In case of an error, -1 is returned. If no
  // requested values are found, 0 is returned, otherwise correct
  // number of retrieved values are returned.

  int thread_grp_list (int grp_id,
                       ACE_thread_t thread_list[],
                       size_t n);
  // Returns in <thread_list> a list of up to <n> thread ids in a
  // group <grp_id>.  The caller must allocate the memory for
  // <thread_list>.  In case of an error, -1 is returned. If no
  // requested values are found, 0 is returned, otherwise correct
  // number of retrieved values are returned.

  int hthread_grp_list (int grp_id,
                        ACE_hthread_t hthread_list[],
                        size_t n);
  // Returns in <hthread_list> a list of up to <n> thread handles in
  // a group <grp_id>.  The caller must allocate memory for
  // <hthread_list>.

  int task_all_list (ACE_Task_Base *task_list[],
                     size_t n);
  // Returns in <task_list> a list of up to <n> <ACE_Tasks>.  The
  // caller must allocate the memory for <task_list>.  In case of an
  // error, -1 is returned. If no requested values are found, 0 is
  // returned, otherwise correct number of retrieved values are
  // returned.

  int thread_all_list (ACE_thread_t thread_list[],
                       size_t n);
  // Returns in <thread_list> a list of up to <n> thread ids.  The
  // caller must allocate the memory for <thread_list>.  In case of an
  // error, -1 is returned. If no requested values are found, 0 is
  // returned, otherwise correct number of retrieved values are
  // returned.

  // = Set/get group ids for a particular task.
  int set_grp (ACE_Task_Base *task, int grp_id);
  int get_grp (ACE_Task_Base *task, int &grp_id);

  int count_threads (void) const;
  // Return a count of the current number of threads active in the
  // <Thread_Manager>.

#if !defined(ACE_USE_ONE_SHOT_AT_THREAD_EXIT)
  int at_exit (ACE_At_Thread_Exit* cleanup);
  // Register an At_Thread_Exit hook and the ownership is acquire by
  // Thread_Descriptor, this is the usual case when the AT is dynamically
  // allocated.

  int at_exit (ACE_At_Thread_Exit& cleanup);
  // Register an At_Thread_Exit hook and the ownership is retained for the
  // caller. Normally used when the at_exit hook is created in stack.
#endif /* !ACE_USE_ONE_SHOT_AT_THREAD_EXIT */

  int at_exit (void *object,
               ACE_CLEANUP_FUNC cleanup_hook,
               void *param);
  // *** This function is deprecated.  Please use the previous two
  // *** at_exit method.  Notice that you should avoid mixing this method
  // *** with the previous two at_exit methods.
  //
  // Register an object (or array) for cleanup at
  // thread termination.  "cleanup_hook" points to a (global, or
  // static member) function that is called for the object or array
  // when it to be destroyed.  It may perform any necessary cleanup
  // specific for that object or its class.  "param" is passed as the
  // second parameter to the "cleanup_hook" function; the first
  // parameter is the object (or array) to be destroyed.
  // "cleanup_hook", for example, may delete the object (or array).
  // If <cleanup_hook> == 0, the <object> will _NOT_ get cleanup at
  // thread exit.  You can use this to cancel the previously added
  // at_exit.

  void wait_on_exit (int dowait);
  int  wait_on_exit (void);
  // Access function to determine whether the Thread_Manager will
  // wait for its thread to exit or not when being closing down.

  void dump (void);
  // Dump the state of an object.

  ACE_ALLOC_HOOK_DECLARE;
  // Declare the dynamic allocation hooks.

protected:
  virtual int spawn_i (ACE_THR_FUNC func,
                       void *args,
                       long flags,
                       ACE_thread_t * = 0,
                       ACE_hthread_t *t_handle = 0,
                       long priority = ACE_DEFAULT_THREAD_PRIORITY,
                       int grp_id = -1,
                       void *stack = 0,
                       size_t stack_size = 0,
                       ACE_Task_Base *task = 0);
  // Create a new thread (must be called with locks held).

  void run_thread_exit_hooks (int i);
  // Run the registered hooks when the thread exits.

  ACE_Thread_Descriptor *find_thread (ACE_thread_t t_id);
  // Locate the index of the table slot occupied by <t_id>.  Returns
  // -1 if <t_id> is not in the table doesn't contain <t_id>.

  ACE_Thread_Descriptor *find_hthread (ACE_hthread_t h_id);
  // Locate the index of the table slot occupied by <h_id>.  Returns
  // -1 if <h_id> is not in the table doesn't contain <h_id>.

  ACE_Thread_Descriptor *find_task (ACE_Task_Base *task,
                                    int index = -1);
  // Locate the thread descriptor address of the list occupied by
  // <task>.  Returns 0 if <task> is not in the table doesn't contain
  // <task>.

  int insert_thr (ACE_thread_t t_id,
                  ACE_hthread_t,
                  int grp_id = -1,
                  long flags = 0);
  // Insert a thread in the table (checks for duplicates).

  int append_thr (ACE_thread_t t_id, ACE_hthread_t,
                  ACE_UINT32,
                  int grp_id,
                  ACE_Task_Base *task = 0,
                  long flags = 0,
                  ACE_Thread_Descriptor *td = 0);
  // Append a thread in the table (adds at the end, growing the table
  // if necessary).

  void remove_thr (ACE_Thread_Descriptor *td,
                   int close_handler);
  // Remove thread from the table.

  void remove_thr_all (void);
  // Remove all threads from the table.

  // = The following four methods implement a simple scheme for
  // operating on a collection of threads atomically.

  int check_state (ACE_UINT32 state,
                   ACE_thread_t thread,
                   int enable = 1);
  // Efficiently check whether <thread> is in a particular <state>.
  // This call updates the TSS cache if possible to speed up
  // subsequent searches.

  int apply_task (ACE_Task_Base *task,
                  ACE_THR_MEMBER_FUNC,
                  int = 0);
  // Apply <func> to all members of the table that match the <task>

  int apply_grp (int grp_id,
                 ACE_THR_MEMBER_FUNC func,
                 int arg = 0);
  // Apply <func> to all members of the table that match the <grp_id>.

  int apply_all (ACE_THR_MEMBER_FUNC,
                 int  = 0);
  // Apply <func> to all members of the table.

  int join_thr (ACE_Thread_Descriptor *td,
                int = 0);
  // Join the thread described in <tda>.

  int resume_thr (ACE_Thread_Descriptor *td,
                  int = 0);
  // Resume the thread described in <tda>.

  int suspend_thr (ACE_Thread_Descriptor *td,
                   int = 0);
  // Suspend the thread described in <tda>.

  int kill_thr (ACE_Thread_Descriptor *td,
                int signum);
  // Send signal <signum> to the thread described in <tda>.

  int cancel_thr (ACE_Thread_Descriptor *td,
                  int async_cancel = 0);
  // Set the cancellation flag for the thread described in <tda>.

  int register_as_terminated (ACE_Thread_Descriptor *td);
  // Register a thread as terminated and put it into the <terminated_thr_list_>.

  ACE_Double_Linked_List<ACE_Thread_Descriptor> thr_list_;
  // Keeping a list of thread descriptors within the thread manager.
  // Double-linked list enables us to cache the entries in TSS
  // and adding/removing thread descriptor entries without
  // affecting other thread's descriptor entries.

#if !defined (VXWORKS)
  ACE_Double_Linked_List<ACE_Thread_Descriptor_Base> terminated_thr_list_;
  // Collect terminated but not yet joined thread entries.
#endif /* VXWORKS */

  ACE_Unbounded_Queue<ACE_Thread_Descriptor*> thr_to_be_removed_;
  // Collect pointers to thread descriptors of threads to be removed later.

  int grp_id_;
  // Keeps track of the next group id to assign.

  int automatic_wait_;
  // Set if we want the Thread_Manager to wait on all threads before
  // being closed, reset otherwise.

  // = ACE_Thread_Mutex and condition variable for synchronizing termination.
#if defined (ACE_HAS_THREADS)
  ACE_Thread_Mutex lock_;
  // Serialize access to the <zero_cond_>.

  ACE_Condition_Thread_Mutex zero_cond_;
  // Keep track of when there are no more threads.
#endif /* ACE_HAS_THREADS */

private:
  ACE_Locked_Free_List<ACE_Thread_Descriptor, ACE_SYNCH_MUTEX> thread_desc_freelist_;

  static ACE_Thread_Manager *thr_mgr_;
  // Pointer to a process-wide <ACE_Thread_Manager>.

  static int delete_thr_mgr_;
  // Must delete the <thr_mgr_> if non-0.
};

#if defined (__ACE_INLINE__)
#include "ace/Thread_Manager.i"
#endif /* __ACE_INLINE__ */

#endif /* ACE_THREAD_MANAGER_H */