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// Package : omnithread
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// omnithread/nt.cc Created : 6/95 tjr
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// Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
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// This file is part of the omnithread library
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// The omnithread library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Library General Public License for more details.
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// You should have received a copy of the GNU Library General Public
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// License along with this library; if not, write to the Free
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// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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// Implementation of OMNI thread abstraction for NT threads
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#include "omnithread.h"
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//#include <iostream.h> or #include <iostream> if DB is on.
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static void get_time_now(unsigned long* abs_sec, unsigned long* abs_nsec);
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///////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////
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omni_mutex::omni_mutex(void)
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InitializeCriticalSection(&crit);
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omni_mutex::~omni_mutex(void)
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DeleteCriticalSection(&crit);
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omni_mutex::lock(void)
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EnterCriticalSection(&crit);
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omni_mutex::unlock(void)
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LeaveCriticalSection(&crit);
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///////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////
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// Condition variables are tricky to implement using NT synchronisation
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// primitives, since none of them have the atomic "release mutex and wait to be
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// signalled" which is central to the idea of a condition variable. To get
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// around this the solution is to record which threads are waiting and
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// explicitly wake up those threads.
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// Here we implement a condition variable using a list of waiting threads
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// (protected by a critical section), and a per-thread semaphore (which
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// actually only needs to be a binary semaphore).
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// To wait on the cv, a thread puts itself on the list of waiting threads for
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// that cv, then releases the mutex and waits on its own personal semaphore. A
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// signalling thread simply takes a thread from the head of the list and kicks
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// that thread's semaphore. Broadcast is simply implemented by kicking the
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// semaphore of each waiting thread.
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// The only other tricky part comes when a thread gets a timeout from a timed
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// wait on its semaphore. Between returning with a timeout from the wait and
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// entering the critical section, a signalling thread could get in, kick the
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// waiting thread's semaphore and remove it from the list. If this happens,
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// the waiting thread's semaphore is now out of step so it needs resetting, and
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// the thread should indicate that it was signalled rather than that it timed
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// It is possible that the thread calling wait or timedwait is not a
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// omni_thread. In this case we have to provide a temporary data structure,
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// i.e. for the duration of the call, for the thread to link itself on the
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// list of waiting threads. _internal_omni_thread_dummy provides such
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// a data structure and _internal_omni_thread_helper is a helper class to
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// deal with this special case for wait() and timedwait(). Once created,
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// the _internal_omni_thread_dummy is cached for use by the next wait() or
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// timedwait() call from a non-omni_thread. This is probably worth doing
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// because creating a Semaphore is quite heavy weight.
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class _internal_omni_thread_helper;
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class _internal_omni_thread_dummy : public omni_thread {
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inline _internal_omni_thread_dummy() : next(0) { }
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inline ~_internal_omni_thread_dummy() { }
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friend class _internal_omni_thread_helper;
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_internal_omni_thread_dummy* next;
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class _internal_omni_thread_helper {
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inline _internal_omni_thread_helper() {
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t = omni_thread::self();
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omni_mutex_lock sync(cachelock);
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d = new _internal_omni_thread_dummy;
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inline ~_internal_omni_thread_helper() {
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omni_mutex_lock sync(cachelock);
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inline operator omni_thread* () { return t; }
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inline omni_thread* operator->() { return t; }
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static _internal_omni_thread_dummy* cache;
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static omni_mutex cachelock;
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_internal_omni_thread_dummy* d;
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_internal_omni_thread_dummy* _internal_omni_thread_helper::cache = 0;
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omni_mutex _internal_omni_thread_helper::cachelock;
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omni_condition::omni_condition(omni_mutex* m) : mutex(m)
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InitializeCriticalSection(&crit);
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waiting_head = waiting_tail = NULL;
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omni_condition::~omni_condition(void)
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DeleteCriticalSection(&crit);
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DB( if (waiting_head != NULL) {
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cerr << "omni_condition::~omni_condition: list of waiting threads "
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omni_condition::wait(void)
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_internal_omni_thread_helper me;
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EnterCriticalSection(&crit);
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me->cond_next = NULL;
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me->cond_prev = waiting_tail;
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if (waiting_head == NULL)
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waiting_tail->cond_next = me;
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me->cond_waiting = TRUE;
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LeaveCriticalSection(&crit);
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DWORD result = WaitForSingleObject(me->cond_semaphore, INFINITE);
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if (result != WAIT_OBJECT_0)
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throw omni_thread_fatal(GetLastError());
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omni_condition::timedwait(unsigned long abs_sec, unsigned long abs_nsec)
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_internal_omni_thread_helper me;
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EnterCriticalSection(&crit);
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me->cond_next = NULL;
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me->cond_prev = waiting_tail;
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if (waiting_head == NULL)
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waiting_tail->cond_next = me;
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me->cond_waiting = TRUE;
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LeaveCriticalSection(&crit);
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unsigned long now_sec, now_nsec;
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get_time_now(&now_sec, &now_nsec);
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DWORD timeout = (abs_sec-now_sec) * 1000 + (abs_nsec-now_nsec) / 1000000;
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if ((abs_sec <= now_sec) && ((abs_sec < now_sec) || (abs_nsec < abs_nsec)))
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DWORD result = WaitForSingleObject(me->cond_semaphore, timeout);
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if (result == WAIT_TIMEOUT) {
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EnterCriticalSection(&crit);
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if (me->cond_waiting) {
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if (me->cond_prev != NULL)
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me->cond_prev->cond_next = me->cond_next;
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waiting_head = me->cond_next;
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if (me->cond_next != NULL)
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me->cond_next->cond_prev = me->cond_prev;
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waiting_tail = me->cond_prev;
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me->cond_waiting = FALSE;
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LeaveCriticalSection(&crit);
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// We timed out but another thread still signalled us. Wait for
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// the semaphore (it _must_ have been signalled) to decrement it
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// again. Return that we were signalled, not that we timed out.
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LeaveCriticalSection(&crit);
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result = WaitForSingleObject(me->cond_semaphore, INFINITE);
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if (result != WAIT_OBJECT_0)
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throw omni_thread_fatal(GetLastError());
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omni_condition::signal(void)
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EnterCriticalSection(&crit);
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if (waiting_head != NULL) {
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omni_thread* t = waiting_head;
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waiting_head = t->cond_next;
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if (waiting_head == NULL)
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waiting_head->cond_prev = NULL;
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t->cond_waiting = FALSE;
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if (!ReleaseSemaphore(t->cond_semaphore, 1, NULL)) {
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int rc = GetLastError();
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LeaveCriticalSection(&crit);
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throw omni_thread_fatal(rc);
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LeaveCriticalSection(&crit);
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omni_condition::broadcast(void)
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EnterCriticalSection(&crit);
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while (waiting_head != NULL) {
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omni_thread* t = waiting_head;
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waiting_head = t->cond_next;
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if (waiting_head == NULL)
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waiting_head->cond_prev = NULL;
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t->cond_waiting = FALSE;
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if (!ReleaseSemaphore(t->cond_semaphore, 1, NULL)) {
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int rc = GetLastError();
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LeaveCriticalSection(&crit);
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throw omni_thread_fatal(rc);
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LeaveCriticalSection(&crit);
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///////////////////////////////////////////////////////////////////////////
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// Counting semaphore
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///////////////////////////////////////////////////////////////////////////
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#define SEMAPHORE_MAX 0x7fffffff
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omni_semaphore::omni_semaphore(unsigned int initial)
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nt_sem = CreateSemaphore(NULL, initial, SEMAPHORE_MAX, NULL);
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if (nt_sem == NULL) {
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DB( cerr << "omni_semaphore::omni_semaphore: CreateSemaphore error "
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<< GetLastError() << endl );
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throw omni_thread_fatal(GetLastError());
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omni_semaphore::~omni_semaphore(void)
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if (!CloseHandle(nt_sem)) {
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DB( cerr << "omni_semaphore::~omni_semaphore: CloseHandle error "
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<< GetLastError() << endl );
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throw omni_thread_fatal(GetLastError());
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omni_semaphore::wait(void)
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if (WaitForSingleObject(nt_sem, INFINITE) != WAIT_OBJECT_0)
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throw omni_thread_fatal(GetLastError());
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omni_semaphore::trywait(void)
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switch (WaitForSingleObject(nt_sem, 0)) {
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throw omni_thread_fatal(GetLastError());
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return 0; /* keep msvc++ happy */
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omni_semaphore::post(void)
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if (!ReleaseSemaphore(nt_sem, 1, NULL))
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throw omni_thread_fatal(GetLastError());
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///////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////
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int omni_thread::init_t::count = 0;
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omni_mutex* omni_thread::next_id_mutex;
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int omni_thread::next_id = 0;
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static DWORD self_tls_index;
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// Initialisation function (gets called before any user code).
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omni_thread::init_t::init_t(void)
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if (count++ != 0) // only do it once however many objects get created.
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DB(cerr << "omni_thread::init: NT implementation initialising\n");
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self_tls_index = TlsAlloc();
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if (self_tls_index == 0xffffffff)
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throw omni_thread_fatal(GetLastError());
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next_id_mutex = new omni_mutex;
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// Create object for this (i.e. initial) thread.
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omni_thread* t = new omni_thread;
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t->_state = STATE_RUNNING;
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if (!DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
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GetCurrentProcess(), &t->handle,
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0, FALSE, DUPLICATE_SAME_ACCESS))
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throw omni_thread_fatal(GetLastError());
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t->nt_id = GetCurrentThreadId();
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DB(cerr << "initial thread " << t->id() << " NT thread id " << t->nt_id
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if (!TlsSetValue(self_tls_index, (LPVOID)t))
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throw omni_thread_fatal(GetLastError());
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if (!SetThreadPriority(t->handle, nt_priority(PRIORITY_NORMAL)))
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throw omni_thread_fatal(GetLastError());
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// Wrapper for thread creation.
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omni_thread_wrapper(void* ptr)
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omni_thread* me = (omni_thread*)ptr;
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DB(cerr << "omni_thread_wrapper: thread " << me->id()
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if (!TlsSetValue(self_tls_index, (LPVOID)me))
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throw omni_thread_fatal(GetLastError());
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// Now invoke the thread function with the given argument.
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if (me->fn_void != NULL) {
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(*me->fn_void)(me->thread_arg);
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if (me->fn_ret != NULL) {
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void* return_value = (*me->fn_ret)(me->thread_arg);
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omni_thread::exit(return_value);
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me->run(me->thread_arg);
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void* return_value = me->run_undetached(me->thread_arg);
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omni_thread::exit(return_value);
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// should never get here.
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// Constructors for omni_thread - set up the thread object but don't
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// construct a detached thread running a given function.
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omni_thread::omni_thread(void (*fn)(void*), void* arg, priority_t pri)
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common_constructor(arg, pri, 1);
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// construct an undetached thread running a given function.
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omni_thread::omni_thread(void* (*fn)(void*), void* arg, priority_t pri)
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common_constructor(arg, pri, 0);
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// construct a thread which will run either run() or run_undetached().
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omni_thread::omni_thread(void* arg, priority_t pri)
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common_constructor(arg, pri, 1);
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// common part of all constructors.
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omni_thread::common_constructor(void* arg, priority_t pri, int det)
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next_id_mutex->lock();
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next_id_mutex->unlock();
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detached = det; // may be altered in start_undetached()
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cond_semaphore = CreateSemaphore(NULL, 0, SEMAPHORE_MAX, NULL);
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if (cond_semaphore == NULL)
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throw omni_thread_fatal(GetLastError());
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cond_next = cond_prev = NULL;
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cond_waiting = FALSE;
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// Destructor for omni_thread.
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omni_thread::~omni_thread(void)
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DB(cerr << "destructor called for thread " << id() << endl);
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if ((handle != NULL) && !CloseHandle(handle))
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throw omni_thread_fatal(GetLastError());
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if (!CloseHandle(cond_semaphore))
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throw omni_thread_fatal(GetLastError());
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omni_thread::start(void)
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omni_mutex_lock l(mutex);
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if (_state != STATE_NEW)
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throw omni_thread_invalid();
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handle = (HANDLE)_beginthreadex(
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throw omni_thread_fatal(GetLastError());
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if (!SetThreadPriority(handle, _priority))
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throw omni_thread_fatal(GetLastError());
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if (ResumeThread(handle) == 0xffffffff)
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throw omni_thread_fatal(GetLastError());
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_state = STATE_RUNNING;
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// Start a thread which will run the member function run_undetached().
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omni_thread::start_undetached(void)
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if ((fn_void != NULL) || (fn_ret != NULL))
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throw omni_thread_invalid();
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// join - simply check error conditions & call WaitForSingleObject.
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omni_thread::join(void** status)
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if ((_state != STATE_RUNNING) && (_state != STATE_TERMINATED)) {
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throw omni_thread_invalid();
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throw omni_thread_invalid();
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throw omni_thread_invalid();
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DB(cerr << "omni_thread::join: doing WaitForSingleObject\n");
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if (WaitForSingleObject(handle, INFINITE) != WAIT_OBJECT_0)
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throw omni_thread_fatal(GetLastError());
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DB(cerr << "omni_thread::join: WaitForSingleObject succeeded\n");
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*status = return_val;
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// Change this thread's priority.
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omni_thread::set_priority(priority_t pri)
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omni_mutex_lock l(mutex);
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if (_state != STATE_RUNNING)
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throw omni_thread_invalid();
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if (!SetThreadPriority(handle, nt_priority(pri)))
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throw omni_thread_fatal(GetLastError());
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// create - construct a new thread object and start it running. Returns thread
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// object if successful, null pointer if not.
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omni_thread::create(void (*fn)(void*), void* arg, priority_t pri)
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omni_thread* t = new omni_thread(fn, arg, pri);
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// undetached version
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omni_thread::create(void* (*fn)(void*), void* arg, priority_t pri)
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omni_thread* t = new omni_thread(fn, arg, pri);
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// exit() _must_ lock the mutex even in the case of a detached thread. This is
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// because a thread may run to completion before the thread that created it has
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// had a chance to get out of start(). By locking the mutex we ensure that the
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// creating thread must have reached the end of start() before we delete the
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// thread object. Of course, once the call to start() returns, the user can
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// still incorrectly refer to the thread object, but that's their problem.
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omni_thread::exit(void* return_value)
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omni_thread* me = self();
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me->_state = STATE_TERMINATED;
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DB(cerr << "omni_thread::exit: thread " << me->id() << " detached "
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<< me->detached << " return value " << return_value << endl);
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me->return_val = return_value;
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DB(cerr << "omni_thread::exit: called with a non-omnithread. Exit quietly." << endl);
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// _endthreadex() does not automatically closes the thread handle.
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// The omni_thread dtor closes the thread handle.
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omni_thread::self(void)
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me = TlsGetValue(self_tls_index);
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DB(cerr << "omni_thread::self: called with a non-ominthread. NULL is returned." << endl);
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return (omni_thread*)me;
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omni_thread::yield(void)
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#define MAX_SLEEP_SECONDS (DWORD)4294966 // (2**32-2)/1000
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omni_thread::sleep(unsigned long secs, unsigned long nanosecs)
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if (secs <= MAX_SLEEP_SECONDS) {
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Sleep(secs * 1000 + nanosecs / 1000000);
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DWORD no_of_max_sleeps = secs / MAX_SLEEP_SECONDS;
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for (DWORD i = 0; i < no_of_max_sleeps; i++)
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Sleep(MAX_SLEEP_SECONDS * 1000);
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Sleep((secs % MAX_SLEEP_SECONDS) * 1000 + nanosecs / 1000000);
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omni_thread::get_time(unsigned long* abs_sec, unsigned long* abs_nsec,
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unsigned long rel_sec, unsigned long rel_nsec)
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get_time_now(abs_sec, abs_nsec);
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*abs_nsec += rel_nsec;
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*abs_sec += rel_sec + *abs_nsec / 1000000000;
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*abs_nsec = *abs_nsec % 1000000000;
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omni_thread::nt_priority(priority_t pri)
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return THREAD_PRIORITY_LOWEST;
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case PRIORITY_NORMAL:
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return THREAD_PRIORITY_NORMAL;
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return THREAD_PRIORITY_HIGHEST;
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throw omni_thread_invalid();
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return 0; /* keep msvc++ happy */
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get_time_now(unsigned long* abs_sec, unsigned long* abs_nsec)
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static int days_in_preceding_months[12]
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= { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
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static int days_in_preceding_months_leap[12]
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= { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 };
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*abs_nsec = st.wMilliseconds * 1000000;
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// this formula should work until 1st March 2100
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DWORD days = ((st.wYear - 1970) * 365 + (st.wYear - 1969) / 4
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? days_in_preceding_months[st.wMonth - 1]
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: days_in_preceding_months_leap[st.wMonth - 1])
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*abs_sec = st.wSecond + 60 * (st.wMinute + 60 * (st.wHour + 24 * days));
added
removed
ica/win32/src/omnithread/nt.cpp
