1 files changed, 103 insertions, 0 deletions
diff --git a/src/corelib/doc/snippets/code/src_corelib_thread_qfuture.cpp b/src/corelib/doc/snippets/code/src_corelib_thread_qfuture.cpp
index dfa9b670e7..66fa62f6b3 100644
--- a/src/corelib/doc/snippets/code/src_corelib_thread_qfuture.cpp
+++ b/src/corelib/doc/snippets/code/src_corelib_thread_qfuture.cpp
@@ -72,3 +72,106 @@ i.toBack();
 while (i.hasPrevious())
     qDebug() << i.previous();
 //! [2]
+
+//! [3]
+using NetworkReply = std::variant<QByteArray, QNetworkReply::NetworkError>;
+
+enum class IOError { FailedToRead, FailedToWrite };
+using IOResult = std::variant<QString, IOError>;
+//! [3]
+
+//! [4]
+QFuture<IOResult> future = QtConcurrent::run([url] {
+        ...
+        return NetworkReply(QNetworkReply::TimeoutError);
+}).then([](NetworkReply reply) {
+    if (auto error = std::get_if<QNetworkReply::NetworkError>(&reply))
+        return IOResult(IOError::FailedToRead);
+
+    auto data = std::get_if<QByteArray>(&reply);
+    // try to write *data and return IOError::FailedToWrite on failure
+    ...
+});
+
+auto result = future.result();
+if (auto filePath = std::get_if<QString>(&result)) {
+    // do something with *filePath
+else
+    // process the error
+//! [4]
+
+//! [5]
+QFuture<int> future = ...;
+    future.then([](QFuture<int> f) {
+        try {
+            ...
+            auto result = f.result();
+            ...
+        } catch (QException &e) {
+            // handle the exception
+        }
+    }).then(...);
+//! [5]
+
+//! [6]
+QFuture<int> parentFuture = ...;
+auto continuation = parentFuture.then([](int res1){ ... }).then([](int res2){ ... })...
+...
+// parentFuture throws an exception
+try {
+    auto result = continuation.result();
+} catch (QException &e) {
+    // handle the exception
+}
+//! [6]
+
+//! [7]
+QFuture<int> future = ...;
+auto resultFuture = future.then([](int res) {
+    ...
+    throw Error();
+    ...
+}).onFailed([](const Error &e) {
+    // Handle exceptions of type Error
+    ...
+    return -1;
+}).onFailed([] {
+    // Handle all other types of errors
+    ...
+    return -1;
+});
+
+auto result = resultFuture.result(); // result is -1
+//! [7]
+
+//! [8]
+QFuture<int> future = ...;
+future.then([](int res) {
+    ...
+    throw std::runtime_error("message");
+    ...
+}).onFailed([](const std::exception &e) {
+    // This handler will be invoked
+}).onFailed([](const std::runtime_error &e) {
+    // This handler won't be invoked, because of the handler above.
+});
+//! [8]
+
+//! [9]
+QFuture<int> future = ...;
+auto resultFuture = future.then([](int res) {
+    ...
+    throw Error("message");
+    ...
+}).onFailed([](const std::exception &e) {
+    // Won't be invoked
+}).onFailed([](const QException &e) {
+    // Won't be invoked
+});
+
+try {
+    auto result = resultFuture.result();
+} catch(...) {
+    // Handle the exception
+}
+//! [9]