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| -rw-r--r-- | src/port/pgsleep.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/port/pgsleep.c b/src/port/pgsleep.c index 1e2c74dbab8..3e6b6656257 100644 --- a/src/port/pgsleep.c +++ b/src/port/pgsleep.c @@ -29,6 +29,16 @@ * 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. + * + * CAUTION: the behavior when a signal arrives during the sleep is platform + * dependent. On most Unix-ish platforms, a signal does not terminate the + * sleep; but on some, it will (the Windows implementation also allows signals + * to terminate pg_usleep). And there are platforms where not only does a + * signal not terminate the sleep, but it actually resets the timeout counter + * so that the sleep effectively starts over! It is therefore rather hazardous + * to use this for long sleeps; a continuing stream of signal events could + * prevent the sleep from ever terminating. Better practice for long sleeps + * is to use WaitLatch() with a timeout. */ void pg_usleep(long microsec) |