/* -*- C++ -*- */
// $Id: Thread.h,v 4.21 1999/03/10 17:05:14 levine Exp $

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

#ifndef ACE_THREAD_H
#define ACE_THREAD_H

#include "ace/ACE.h"

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

class ACE_Export ACE_Thread
{
  // = TITLE
  //     Provides a wrapper for threads.
  //
  // = DESCRIPTION
  //     This class provides a common interface that is mapped onto
  //     POSIX Pthreads, Solaris threads, Win32 threads, VxWorks
  //     threads, or pSoS threads.  Note, however, that it is
  //     generally a better idea to use the <ACE_Thread_Manager>
  //     programming API rather than the <ACE_Thread> API since the
  //     thread manager is more powerful.
public:
  static int spawn (ACE_THR_FUNC func,
                    void *arg = 0,
                    long flags = THR_NEW_LWP | THR_JOINABLE,
                    ACE_thread_t *t_id = 0,
                    ACE_hthread_t *t_handle = 0,
                    long priority = ACE_DEFAULT_THREAD_PRIORITY,
                    void *stack = 0,
                    size_t stack_size = 0,
                    ACE_Thread_Adapter *thread_adapter = 0);
  // Creates a new thread having <flags> attributes and running <func>
  // with <args> (if <thread_adapter> is non-0 then <func> and <args>
  // are ignored and are obtained from <thread_adapter>).  <thr_id>
  // and <t_handle> are set to the thread's ID and handle (?),
  // respectively.  The thread runs at <priority> priority (see
  // below).
  //
  // The <flags> are a bitwise-OR of the following:
  // = BEGIN<INDENT>
  // THR_CANCEL_DISABLE, THR_CANCEL_ENABLE, THR_CANCEL_DEFERRED,
  // THR_CANCEL_ASYNCHRONOUS, THR_BOUND, THR_NEW_LWP, THR_DETACHED,
  // THR_SUSPENDED, THR_DAEMON, THR_JOINABLE, THR_SCHED_FIFO,
  // THR_SCHED_RR, THR_SCHED_DEFAULT
  // = END<INDENT>
  //
  // By default, or if <priority> is set to
  // ACE_DEFAULT_THREAD_PRIORITY, an "appropriate" priority value for
  // the given scheduling policy (specified in <flags}>, e.g.,
  // <THR_SCHED_DEFAULT>) is used.  This value is calculated
  // dynamically, and is the median value between the minimum and
  // maximum priority values for the given policy.  If an explicit
  // value is given, it is used.  Note that actual priority values are
  // EXTREMEMLY implementation-dependent, and are probably best
  // avoided.
  //
  // Note that <thread_adapter> is always deleted by <thr_create>,
  // therefore it must be allocated with global operator new.

  static int spawn_n (size_t n,
                      ACE_THR_FUNC func,
                      void *arg = 0,
                      long flags = THR_NEW_LWP | THR_JOINABLE,
                      long priority = ACE_DEFAULT_THREAD_PRIORITY,
                      void *stack[] = 0,
                      size_t stack_size[] = 0,
                      ACE_Thread_Adapter *thread_adapter = 0);
  // Spawn N new threads, which execute <func> with argument <arg> (if
  // <thread_adapter> is non-0 then <func> and <args> are ignored and
  // are obtained from <thread_adapter>).  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.  Likewise, if <stack_size>
  // != 0 it is assumed to be an array of <n> values indicating how
  // big each of the corresponding <stack>s are.  Returns the number
  // of threads actually spawned (if this doesn't equal the number
  // requested then something has gone wrong and <errno> will
  // explain...).
  //
  // See also <spawn>.

  static int spawn_n (ACE_thread_t thread_ids[],
                      size_t n,
                      ACE_THR_FUNC func,
                      void *arg,
                      long flags,
                      long priority = ACE_DEFAULT_THREAD_PRIORITY,
                      void *stack[] = 0,
                      size_t stack_size[] = 0,
                      ACE_hthread_t thread_handles[] = 0,
                      ACE_Thread_Adapter *thread_adapter = 0);
  // Spawn <n> new threads, which execute <func> with argument <arg>
  // (if <thread_adapter> is non-0 then <func> and <args> are ignored
  // and are obtained from <thread_adapter>).  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
  // the number of threads actually spawned (if this doesn't equal the
  // number requested then something has gone wrong and <errno> will
  // explain...).
  //
  // See also <spawn>.

  static int join (ACE_thread_t,
                   ACE_thread_t *,
                   void **status = 0);
  // Wait for one or more threads to exit.

  static int join (ACE_hthread_t,
                   void ** = 0);
  // Wait for one thread to exit.

  static int resume (ACE_hthread_t);
  // Continue the execution of a previously suspended thread.

  static int suspend (ACE_hthread_t);
  // Suspend the execution of a particular thread.

  static int getprio (ACE_hthread_t, int &prio);
  // Get the priority of a particular thread.

  static int setprio (ACE_hthread_t, int prio);
  // Set the priority of a particular thread.

  static int kill (ACE_thread_t, int signum);
  // Send a signal to the thread.

  static void yield (void);
  // Yield the thread to another.

  static void self (ACE_hthread_t &t_handle);
  // Return the unique kernel handle of the thread.  Note that on
  // Win32 this is actually a pseudohandle, which cannot be shared
  // with other processes or waited on by threads.  To locate the real
  // handle, please use the <ACE_Thread_Manager::thr_self> method.

  static ACE_thread_t self (void);
  // Return the unique ID of the thread.

  static void exit (void *status = 0);
  // Exit the current thread and return "status".
  // Should _not_ be called by main thread.

  static int getconcurrency (void);
  // Get the LWP concurrency level of the process.

  static int setconcurrency (int new_level);
  // Set the LWP concurrency level of the process.

  static int sigsetmask (int how,
                         const sigset_t *sigset,
                         sigset_t *osigset = 0);
  // Change and/or examine calling thread's signal mask.

  static int keycreate (ACE_thread_key_t *keyp,
#if defined (ACE_HAS_THR_C_DEST)
                        ACE_THR_C_DEST destructor,
#else
                        ACE_THR_DEST destructor,
#endif /* ACE_HAS_THR_C_DEST */
                        void * = 0);
  // Allocates a <keyp> that is used to identify data that is specific
  // to each thread in the process.  The key is global to all threads
  // in the process.

  static int keyfree (ACE_thread_key_t key);
  // Free up the key so that other threads can reuse it.

  static int setspecific (ACE_thread_key_t key,
                          void *value);
  // Bind value to the thread-specific data key, <key>, for the calling
  // thread.

  static int getspecific (ACE_thread_key_t key,
                          void **valuep);
  // Stores the current value bound to <key> for the calling thread
  // into the location pointed to by <valuep>.

  static int disablecancel (struct cancel_state *old_state);
  // Disable thread cancellation.

  static int enablecancel (struct cancel_state *old_state,
                           int flag);
  // Enable thread cancellation.

  static int setcancelstate (struct cancel_state &new_state,
                             struct cancel_state *old_state);
  // Set the cancellation state.

  static int cancel (ACE_thread_t t_id);
  // Cancel a thread.

  static void testcancel (void);
  // Test the cancel.

private:
  ACE_Thread (void);
  // Ensure that we don't get instantiated.
};

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