QtConcurrent: Handle running with promise inside QTaskBuilder

Please note, that in case of run with promise it doesn't make
sense to provide the overload taking the FutureResult, as if we are
going to ignore the returned QFuture object, we can't communicate
with the passed QPromise.

Fixes: QTBUG-87083
Change-Id: I4066506736c2bbeea3e42030b9495f13e06cb27e
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/concurrent/doc/snippets/code/src_concurrent_qtconcurrenttask.cpp b/src/concurrent/doc/snippets/code/src_concurrent_qtconcurrenttask.cpp
index b067b49e7e..267d6ebc1e 100644
--- a/src/concurrent/doc/snippets/code/src_concurrent_qtconcurrenttask.cpp
+++ b/src/concurrent/doc/snippets/code/src_concurrent_qtconcurrenttask.cpp
@@ -129,3 +129,12 @@ QtConcurrent::task([]{ return 42; }).withPriority(10).spawn();
 //! [11]
 QtConcurrent::task([]{ qDebug("Hello, world!"); }).spawn(FutureResult::Ignore);
 //! [11]
+
+//! [12]
+void increment(QPromise<int> &promise, int i)
+{
+    promise.addResult(i + 1);
+}
+
+int result = QtConcurrent::task(&increment).withArguments(10).spawn().result(); // result == 11
+//! [12]