diff options
authorBradley T. Hughes <>2012-01-10 13:43:51 +0100
committerQt by Nokia <>2012-01-10 16:11:15 +0100
commit7776beacf720cf4478767f5b75440c4a359d8bcf (patch)
parent46b2e5f37d124a66f6f930abc64a0c1da55bbfde (diff)
Document timer accuracy behavior on UNIX.
Change-Id: I5e8b383cc4d8ce0d249be164c5ef596328bdc50c Reviewed-by: Thiago Macieira <>
1 files changed, 9 insertions, 1 deletions
diff --git a/src/corelib/global/qnamespace.qdoc b/src/corelib/global/qnamespace.qdoc
index dbc399809f..3c2697e1f8 100644
--- a/src/corelib/global/qnamespace.qdoc
+++ b/src/corelib/global/qnamespace.qdoc
@@ -2876,9 +2876,17 @@
\value CoarseTimer Coarse timers try to keep accuracy within 5% of the desired interval
\value VeryCoarseTimer Very coarse timers only keep full second accuracy
+ On UNIX (including Linux and Mac OS X), Qt will keep millisecond accuracy
+ for Qt::PreciseTimer. For Qt::CoarseTimer, the interval will be adjusted up
+ to 5% to align the timer with other timers that are expected to fire at or
+ around the same time. The objective is to make most timers wake up at the
+ same time, thereby reducing CPU wakeups and power consumption.
On Windows, Qt will use Windows's Multimedia timer facility (if available)
for Qt::PreciseTimer and normal Windows timers for Qt::CoarseTimer and
- Qt::VeryCoarseTimer. The interval for Qt::VeryCoarseTimer is rounded to the
+ Qt::VeryCoarseTimer.
+ On all platforms, the interval for Qt::VeryCoarseTimer is rounded to the
nearest full second (e.g. an interval of 23500ms will be rounded to
24000ms, and 20300ms to 20000ms).