QThread::start(): priority has no effect on Linux systems

The default scheduling policy on Linux doesn't allow specifying thread
priorities, so the priority passed to start() and setPriority() has no
effect. Document this.

Task number: 249997
Reviewed-by: Kavindra Devi Palaraja <kavindra.palaraja@nokia.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/corelib/thread/qthread.cpp b/src/corelib/thread/qthread.cpp
index 7f8789744e..2fb6335644 100644
--- a/src/corelib/thread/qthread.cpp
+++ b/src/corelib/thread/qthread.cpp
@@ -297,6 +297,12 @@ void QAdoptedThread::run()
     priority parameter. If the thread is already running, this
     function does nothing.
 
+    The effect of the \a priority parameter is dependent on the
+    operating system's scheduling policy. In particular, the \a priority
+    will be ignored on systems that do not support thread priorities
+    (such as on Linux, see http://linux.die.net/man/2/sched_setscheduler
+    for more details).
+
     \sa run(), terminate()
 */
 
@@ -590,6 +596,12 @@ void QThread::cleanup()
     The \a priority argument can be any value in the \c
     QThread::Priority enum except for \c InheritPriorty.
 
+    The effect of the \a priority parameter is dependent on the
+    operating system's scheduling policy. In particular, the \a priority
+    will be ignored on systems that do not support thread priorities
+    (such as on Linux, see http://linux.die.net/man/2/sched_setscheduler
+    for more details).
+
     \sa Priority priority() start()
 */