1 /*-------------------------------------------------------------------------
4 * Microsoft Windows Win32 Timer Implementation
6 * Limitations of this implementation:
8 * - Does not support interval timer (value->it_interval)
9 * - Only supports ITIMER_REAL
11 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
14 * $PostgreSQL: pgsql/src/backend/port/win32/timer.c,v 1.15 2008/01/01 19:45:51 momjian Exp $
16 *-------------------------------------------------------------------------
21 #include "libpq/pqsignal.h"
24 /* Communication area for inter-thread communication */
25 typedef struct timerCA
27 struct itimerval value;
29 CRITICAL_SECTION crit_sec;
32 static timerCA timerCommArea;
33 static HANDLE timerThreadHandle = INVALID_HANDLE_VALUE;
36 /* Timer management thread */
38 pg_timer_thread(LPVOID param)
42 Assert(param == NULL);
50 r = WaitForSingleObjectEx(timerCommArea.event, waittime, FALSE);
51 if (r == WAIT_OBJECT_0)
53 /* Event signalled from main thread, change the timer */
54 EnterCriticalSection(&timerCommArea.crit_sec);
55 if (timerCommArea.value.it_value.tv_sec == 0 &&
56 timerCommArea.value.it_value.tv_usec == 0)
57 waittime = INFINITE; /* Cancel the interrupt */
60 /* WaitForSingleObjectEx() uses milliseconds, round up */
61 waittime = (timerCommArea.value.it_value.tv_usec + 999) / 1000 +
62 timerCommArea.value.it_value.tv_sec * 1000;
64 ResetEvent(timerCommArea.event);
65 LeaveCriticalSection(&timerCommArea.crit_sec);
67 else if (r == WAIT_TIMEOUT)
69 /* Timeout expired, signal SIGALRM and turn it off */
70 pg_queue_signal(SIGALRM);
75 /* Should never happen */
84 * Win32 setitimer emulation by creating a persistent thread
85 * to handle the timer setting and notification upon timeout.
88 setitimer(int which, const struct itimerval * value, struct itimerval * ovalue)
90 Assert(value != NULL);
91 Assert(value->it_interval.tv_sec == 0 && value->it_interval.tv_usec == 0);
92 Assert(which == ITIMER_REAL);
94 if (timerThreadHandle == INVALID_HANDLE_VALUE)
96 /* First call in this backend, create event and the timer thread */
97 timerCommArea.event = CreateEvent(NULL, TRUE, FALSE, NULL);
98 if (timerCommArea.event == NULL)
100 (errmsg_internal("failed to create timer event: %d",
101 (int) GetLastError())));
103 MemSet(&timerCommArea.value, 0, sizeof(struct itimerval));
105 InitializeCriticalSection(&timerCommArea.crit_sec);
107 timerThreadHandle = CreateThread(NULL, 0, pg_timer_thread, NULL, 0, NULL);
108 if (timerThreadHandle == INVALID_HANDLE_VALUE)
110 (errmsg_internal("failed to create timer thread: %d",
111 (int) GetLastError())));
114 /* Request the timer thread to change settings */
115 EnterCriticalSection(&timerCommArea.crit_sec);
117 *ovalue = timerCommArea.value;
118 timerCommArea.value = *value;
119 LeaveCriticalSection(&timerCommArea.crit_sec);
120 SetEvent(timerCommArea.event);