timer.c File Reference

#include "postgres.h"

Include dependency graph for timer.c:

Go to the source code of this file.

Data Structures
struct	timerCA

Typedefs
typedef struct timerCA	timerCA

Functions
static DWORD WINAPI	pg_timer_thread (LPVOID param)
int	setitimer (int which, const struct itimerval *value, struct itimerval *ovalue)

Variables
static timerCA	timerCommArea
static HANDLE	timerThreadHandle = INVALID_HANDLE_VALUE

Typedef Documentation

timerCA

typedef struct timerCA timerCA

Function Documentation

pg_timer_thread()

static DWORD WINAPI pg_timer_thread ( LPVOID  param )

static

Definition at line 36 of file timer.c.

{
    DWORD       waittime;
 
    Assert(param == NULL);
 
    waittime = INFINITE;
 
    for (;;)
    {
        int         r;
 
        r = WaitForSingleObjectEx(timerCommArea.event, waittime, FALSE);
        if (r == WAIT_OBJECT_0)
        {
            /* Event signaled from main thread, change the timer */
            EnterCriticalSection(&timerCommArea.crit_sec);
            if (timerCommArea.value.it_value.tv_sec == 0 &&
                timerCommArea.value.it_value.tv_usec == 0)
                waittime = INFINITE;    /* Cancel the interrupt */
            else
            {
                /* WaitForSingleObjectEx() uses milliseconds, round up */
                waittime = (timerCommArea.value.it_value.tv_usec + 999) / 1000 +
                    timerCommArea.value.it_value.tv_sec * 1000;
            }
            ResetEvent(timerCommArea.event);
            LeaveCriticalSection(&timerCommArea.crit_sec);
        }
        else if (r == WAIT_TIMEOUT)
        {
            /* Timeout expired, signal SIGALRM and turn it off */
            pg_queue_signal(SIGALRM);
            waittime = INFINITE;
        }
        else
        {
            /* Should never happen */
            Assert(false);
        }
    }
 
    return 0;
}

References Assert, timerCA::crit_sec, timerCA::event, itimerval::it_value, pg_queue_signal(), SIGALRM, timerCommArea, and timerCA::value.

Referenced by setitimer().

setitimer()

int setitimer	(	int	which,
		const struct itimerval *	value,
		struct itimerval *	ovalue
	)

Definition at line 86 of file timer.c.

{
    Assert(value != NULL);
    Assert(value->it_interval.tv_sec == 0 && value->it_interval.tv_usec == 0);
    Assert(which == ITIMER_REAL);
 
    if (timerThreadHandle == INVALID_HANDLE_VALUE)
    {
        /* First call in this backend, create event and the timer thread */
        timerCommArea.event = CreateEvent(NULL, TRUE, FALSE, NULL);
        if (timerCommArea.event == NULL)
            ereport(FATAL,
                    (errmsg_internal("could not create timer event: error code %lu",
                                     GetLastError())));
 
        MemSet(&timerCommArea.value, 0, sizeof(struct itimerval));
 
        InitializeCriticalSection(&timerCommArea.crit_sec);
 
        timerThreadHandle = CreateThread(NULL, 0, pg_timer_thread, NULL, 0, NULL);
        if (timerThreadHandle == INVALID_HANDLE_VALUE)
            ereport(FATAL,
                    (errmsg_internal("could not create timer thread: error code %lu",
                                     GetLastError())));
    }
 
    /* Request the timer thread to change settings */
    EnterCriticalSection(&timerCommArea.crit_sec);
    if (ovalue)
        *ovalue = timerCommArea.value;
    timerCommArea.value = *value;
    LeaveCriticalSection(&timerCommArea.crit_sec);
    SetEvent(timerCommArea.event);
 
    return 0;
}

References Assert, timerCA::crit_sec, ereport, errmsg_internal(), timerCA::event, FATAL, ITIMER_REAL, MemSet, pg_timer_thread(), timerCommArea, timerThreadHandle, timerCA::value, and value.

Referenced by do_watch(), fork_process(), and schedule_alarm().

Variable Documentation

timerCommArea

timerCA timerCommArea

static

Definition at line 30 of file timer.c.

Referenced by pg_timer_thread(), and setitimer().

timerThreadHandle

HANDLE timerThreadHandle = INVALID_HANDLE_VALUE

static

Definition at line 31 of file timer.c.

Referenced by setitimer().