pgsleep.c

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/*-------------------------------------------------------------------------
 *
 * pgsleep.c
 *     Portable delay handling.
 *
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 *
 * src/port/pgsleep.c
 *
 *-------------------------------------------------------------------------
 */
#include "c.h"

#include <unistd.h>
#include <sys/time.h>

/*
 * In a Windows backend, we don't use this implementation, but rather
 * the signal-aware version in src/backend/port/win32/signal.c.
 */
#if defined(FRONTEND) || !defined(WIN32)

/*
 * pg_usleep --- delay the specified number of microseconds.
 *
 * NOTE: although the delay is specified in microseconds, the effective
 * resolution is only 1/HZ, or 10 milliseconds, on most Unixen.  Expect
 * the requested delay to be rounded up to the next resolution boundary.
 *
 * On machines where "long" is 32 bits, the maximum delay is ~2000 seconds.
 */
void
pg_usleep(long microsec)
{
    if (microsec > 0)
    {
#ifndef WIN32
        struct timeval delay;

        delay.tv_sec = microsec / 1000000L;
        delay.tv_usec = microsec % 1000000L;
        (void) select(0, NULL, NULL, NULL, &delay);
#else
        SleepEx((microsec < 500 ? 1 : (microsec + 500) / 1000), FALSE);
#endif
    }
}

#endif   /* defined(FRONTEND) || !defined(WIN32) */