Change almost all other uses of qrand() to QRandomGenerator

The vast majority is actually switched to QRandomGenerator::bounded(),
which gives a mostly uniform distribution over the [0, bound)
range. There are very few floating point cases left, as many of those
that did use floating point did not need to, after all. (I did leave
some that were too ugly for me to understand)

This commit also found a couple of calls to rand() instead of qrand().

This commit does not include changes to SSL code that continues to use
qrand() (job for someone else):
  src/network/ssl/qsslkey_qt.cpp
  src/network/ssl/qsslsocket_mac.cpp
  tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp

Change-Id: Icd0e0d4b27cb4e5eb892fffd14b5285d43f4afbf
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

50 files changed, 126 insertions, 131 deletions

diff --git a/examples/corelib/ipc/localfortuneserver/server.cpp b/examples/corelib/ipc/localfortuneserver/server.cpp
index 9b8b08bd17..be8d4750d6 100644
--- a/examples/corelib/ipc/localfortuneserver/server.cpp
+++ b/examples/corelib/ipc/localfortuneserver/server.cpp
@@ -106,7 +106,7 @@ void Server::sendFortune()
     QByteArray block;
     QDataStream out(&block, QIODevice::WriteOnly);
     out.setVersion(QDataStream::Qt_5_10);
-    const int fortuneIndex = QRandomGenerator::bounded(0, fortunes.size());
+    const int fortuneIndex = QRandomGenerator::global()->bounded(0, fortunes.size());
     const QString &message = fortunes.at(fortuneIndex);
     out << quint32(message.size());
     out << message;
diff --git a/examples/corelib/json/savegame/game.cpp b/examples/corelib/json/savegame/game.cpp
index c70a50121c..4caec71a03 100644
--- a/examples/corelib/json/savegame/game.cpp
+++ b/examples/corelib/json/savegame/game.cpp
@@ -72,7 +72,7 @@ void Game::newGame()
     mPlayer = Character();
     mPlayer.setName(QStringLiteral("Hero"));
     mPlayer.setClassType(Character::Archer);
-    mPlayer.setLevel(QRandomGenerator::bounded(15, 21));
+    mPlayer.setLevel(QRandomGenerator::global()->bounded(15, 21));
 
     mLevels.clear();
     mLevels.reserve(2);
@@ -81,10 +81,10 @@ void Game::newGame()
     QVector<Character> villageNpcs;
     villageNpcs.reserve(2);
     villageNpcs.append(Character(QStringLiteral("Barry the Blacksmith"),
-                                 QRandomGenerator::bounded(8, 11),
+                                 QRandomGenerator::global()->bounded(8, 11),
                                  Character::Warrior));
     villageNpcs.append(Character(QStringLiteral("Terry the Trader"),
-                                 QRandomGenerator::bounded(6, 8),
+                                 QRandomGenerator::global()->bounded(6, 8),
                                  Character::Warrior));
     village.setNpcs(villageNpcs);
     mLevels.append(village);
@@ -93,13 +93,13 @@ void Game::newGame()
     QVector<Character> dungeonNpcs;
     dungeonNpcs.reserve(3);
     dungeonNpcs.append(Character(QStringLiteral("Eric the Evil"),
-                                 QRandomGenerator::bounded(18, 26),
+                                 QRandomGenerator::global()->bounded(18, 26),
                                  Character::Mage));
     dungeonNpcs.append(Character(QStringLiteral("Eric's Left Minion"),
-                                 QRandomGenerator::bounded(5, 7),
+                                 QRandomGenerator::global()->bounded(5, 7),
                                  Character::Warrior));
     dungeonNpcs.append(Character(QStringLiteral("Eric's Right Minion"),
-                                 QRandomGenerator::bounded(4, 9),
+                                 QRandomGenerator::global()->bounded(4, 9),
                                  Character::Warrior));
     dungeon.setNpcs(dungeonNpcs);
     mLevels.append(dungeon);
diff --git a/examples/corelib/threads/queuedcustomtype/main.cpp b/examples/corelib/threads/queuedcustomtype/main.cpp
index 7084b7538a..1f25fafa1b 100644
--- a/examples/corelib/threads/queuedcustomtype/main.cpp
+++ b/examples/corelib/threads/queuedcustomtype/main.cpp
@@ -126,7 +126,6 @@ int main(int argc, char *argv[])
 //! [main start] //! [register meta-type for queued communications]
     qRegisterMetaType<Block>();
 //! [register meta-type for queued communications]
-    qsrand(QTime::currentTime().elapsed());
 
     Window window;
     window.show();
diff --git a/examples/corelib/threads/queuedcustomtype/renderthread.cpp b/examples/corelib/threads/queuedcustomtype/renderthread.cpp
index f894dd587f..67cedf1e74 100644
--- a/examples/corelib/threads/queuedcustomtype/renderthread.cpp
+++ b/examples/corelib/threads/queuedcustomtype/renderthread.cpp
@@ -50,6 +50,8 @@
 
 #include "renderthread.h"
 
+#include <QRandomGenerator>
+
 RenderThread::RenderThread(QObject *parent)
     : QThread(parent)
 {
@@ -82,9 +84,9 @@ void RenderThread::run()
     for (int s = size; s > 0; --s) {
         for (int c = 0; c < 400; ++c) {
 //![processing the image (start)]
-            int x1 = qMax(0, (qrand() % m_image.width()) - s/2);
+            int x1 = qMax(0, QRandomGenerator::global()->bounded(m_image.width()) - s/2);
             int x2 = qMin(x1 + s/2 + 1, m_image.width());
-            int y1 = qMax(0, (qrand() % m_image.height()) - s/2);
+            int y1 = qMax(0, QRandomGenerator::global()->bounded(m_image.height()) - s/2);
             int y2 = qMin(y1 + s/2 + 1, m_image.height());
             int n = 0;
             int red = 0;
diff --git a/examples/corelib/threads/semaphores/semaphores.cpp b/examples/corelib/threads/semaphores/semaphores.cpp
index 37dd4cda20..145624bb0b 100644
--- a/examples/corelib/threads/semaphores/semaphores.cpp
+++ b/examples/corelib/threads/semaphores/semaphores.cpp
@@ -70,10 +70,9 @@ class Producer : public QThread
 public:
     void run() override
     {
-        qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
         for (int i = 0; i < DataSize; ++i) {
             freeBytes.acquire();
-            buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];
+            buffer[i % BufferSize] = "ACGT"[QRandomGenerator::global()->bounded(4)];
             usedBytes.release();
         }
     }
diff --git a/examples/corelib/threads/waitconditions/waitconditions.cpp b/examples/corelib/threads/waitconditions/waitconditions.cpp
index 9eab28f94c..963ee03a76 100644
--- a/examples/corelib/threads/waitconditions/waitconditions.cpp
+++ b/examples/corelib/threads/waitconditions/waitconditions.cpp
@@ -76,15 +76,13 @@ public:
 
     void run() override
     {
-        qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
-
         for (int i = 0; i < DataSize; ++i) {
             mutex.lock();
             if (numUsedBytes == BufferSize)
                 bufferNotFull.wait(&mutex);
             mutex.unlock();
 
-            buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];
+            buffer[i % BufferSize] = "ACGT"[QRandomGenerator::global()->bounded(4)];
 
             mutex.lock();
             ++numUsedBytes;
diff --git a/examples/corelib/tools/contiguouscache/randomlistmodel.cpp b/examples/corelib/tools/contiguouscache/randomlistmodel.cpp
index f3d8f4b133..ccaa45a28b 100644
--- a/examples/corelib/tools/contiguouscache/randomlistmodel.cpp
+++ b/examples/corelib/tools/contiguouscache/randomlistmodel.cpp
@@ -48,6 +48,7 @@
 **
 ****************************************************************************/
 #include "randomlistmodel.h"
+#include <QRandomGenerator>
 #include <stdlib.h>
 
 static const int bufferSize(500);
@@ -101,6 +102,6 @@ void RandomListModel::cacheRows(int from, int to) const
 //![1]
 QString RandomListModel::fetchRow(int position) const
 {
-    return QString::number(rand() % ++position);
+    return QString::number(QRandomGenerator::global()->bounded(++position));
 }
 //![1]
diff --git a/examples/embedded/flickable/main.cpp b/examples/embedded/flickable/main.cpp
index 9772ba4f55..9367c8b4fe 100644
--- a/examples/embedded/flickable/main.cpp
+++ b/examples/embedded/flickable/main.cpp
@@ -72,7 +72,7 @@ static QStringList colorPairs(int max)
     // randomize it
     colors.clear();
     while (combinedColors.count()) {
-        int i = qrand() % combinedColors.count();
+        int i = QRandomGenerator::global()->bounded(combinedColors.count());
         colors << combinedColors[i];
         combinedColors.removeAt(i);
         if (colors.count() == max)
diff --git a/examples/network/fortuneserver/server.cpp b/examples/network/fortuneserver/server.cpp
index 3915a73bf0..7db81fe07a 100644
--- a/examples/network/fortuneserver/server.cpp
+++ b/examples/network/fortuneserver/server.cpp
@@ -182,7 +182,7 @@ void Server::sendFortune()
     QDataStream out(&block, QIODevice::WriteOnly);
     out.setVersion(QDataStream::Qt_5_10);
 
-    out << fortunes[QRandomGenerator::bounded(fortunes.size())];
+    out << fortunes[QRandomGenerator::global()->bounded(fortunes.size())];
 //! [4] //! [7]
 
     QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
diff --git a/examples/network/threadedfortuneserver/fortuneserver.cpp b/examples/network/threadedfortuneserver/fortuneserver.cpp
index 01b77e2aba..791ffc71f4 100644
--- a/examples/network/threadedfortuneserver/fortuneserver.cpp
+++ b/examples/network/threadedfortuneserver/fortuneserver.cpp
@@ -51,6 +51,8 @@
 #include "fortuneserver.h"
 #include "fortunethread.h"
 
+#include <QRandomGenerator>
+
 #include <stdlib.h>
 
 //! [0]
@@ -70,7 +72,7 @@ FortuneServer::FortuneServer(QObject *parent)
 //! [1]
 void FortuneServer::incomingConnection(qintptr socketDescriptor)
 {
-    QString fortune = fortunes.at(qrand() % fortunes.size());
+    QString fortune = fortunes.at(QRandomGenerator::global()->bounded(fortunes.size()));
     FortuneThread *thread = new FortuneThread(socketDescriptor, fortune, this);
     connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
     thread->start();
diff --git a/examples/network/threadedfortuneserver/main.cpp b/examples/network/threadedfortuneserver/main.cpp
index 3a54585fbc..fdacb28945 100644
--- a/examples/network/threadedfortuneserver/main.cpp
+++ b/examples/network/threadedfortuneserver/main.cpp
@@ -60,6 +60,5 @@ int main(int argc, char *argv[])
     QApplication app(argc, argv);
     Dialog dialog;
     dialog.show();
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
     return app.exec();
 }
diff --git a/examples/network/torrent/main.cpp b/examples/network/torrent/main.cpp
index de7516ed3f..6430d2e5f3 100644
--- a/examples/network/torrent/main.cpp
+++ b/examples/network/torrent/main.cpp
@@ -55,7 +55,6 @@
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
 
     Q_INIT_RESOURCE(icons);
 
diff --git a/examples/network/torrent/torrentclient.cpp b/examples/network/torrent/torrentclient.cpp
index ba87924ff9..95232646ab 100644
--- a/examples/network/torrent/torrentclient.cpp
+++ b/examples/network/torrent/torrentclient.cpp
@@ -692,7 +692,7 @@ void TorrentClient::connectToPeers()
 
     // Start as many connections as we can
     while (!weighedPeers.isEmpty() && ConnectionManager::instance()->canAddConnection()
-           && (qrand() % (ConnectionManager::instance()->maxConnections() / 2))) {
+           && (QRandomGenerator::global()->bounded(ConnectionManager::instance()->maxConnections() / 2))) {
         PeerWireClient *client = new PeerWireClient(ConnectionManager::instance()->clientId(), this);
         RateController::instance()->addSocket(client);
         ConnectionManager::instance()->addConnection(client);
@@ -701,7 +701,7 @@ void TorrentClient::connectToPeers()
         d->connections << client;
 
         // Pick a random peer from the list of weighed peers.
-        TorrentPeer *peer = weighedPeers.takeAt(qrand() % weighedPeers.size());
+        TorrentPeer *peer = weighedPeers.takeAt(QRandomGenerator::global()->bounded(weighedPeers.size()));
         weighedPeers.removeAll(peer);
         peer->connectStart = QDateTime::currentSecsSinceEpoch();
         peer->lastVisited = peer->connectStart;
@@ -1114,7 +1114,7 @@ void TorrentClient::scheduleUploads()
         }
 
         if ((client->peerWireState() & PeerWireClient::ChokingPeer) == 0) {
-            if ((qrand() % 10) == 0)
+            if ((QRandomGenerator::global()->bounded(10)) == 0)
                 client->abort();
             else
                 client->chokePeer();
@@ -1128,7 +1128,7 @@ void TorrentClient::scheduleUploads()
     // random peer to allow it to compete for a position among the
     // downloaders.  (This is known as an "optimistic unchoke".)
     if (!allClients.isEmpty()) {
-        PeerWireClient *client = allClients[qrand() % allClients.size()];
+        PeerWireClient *client = allClients[QRandomGenerator::global()->bounded(allClients.size())];
         if (client->peerWireState() & PeerWireClient::ChokingPeer)
             client->unchokePeer();
     }
@@ -1189,7 +1189,7 @@ void TorrentClient::schedulePieceForClient(PeerWireClient *client)
         piece = d->payloads.value(client);
         if (!piece) {
             QList<TorrentPiece *> values = d->pendingPieces.values();
-            piece = values.value(qrand() % values.size());
+            piece = values.value(QRandomGenerator::global()->bounded(values.size()));
             piece->inProgress = true;
             d->payloads.insert(client, piece);
         }
@@ -1246,14 +1246,14 @@ void TorrentClient::schedulePieceForClient(PeerWireClient *client)
             ++it;
         }
         if (!partialPieces.isEmpty())
-            piece = partialPieces.value(qrand() % partialPieces.size());
+            piece = partialPieces.value(QRandomGenerator::global()->bounded(partialPieces.size()));
 
         if (!piece) {
             // Pick a random piece 3 out of 4 times; otherwise, pick either
             // one of the most common or the least common pieces available,
             // depending on the state we're in.
             int pieceIndex = 0;
-            if (d->state == WarmingUp || (qrand() & 4) == 0) {
+            if (d->state == WarmingUp || (QRandomGenerator::global()->generate() & 4) == 0) {
                 int *occurrences = new int[d->pieceCount];
                 memset(occurrences, 0, d->pieceCount * sizeof(int));
 
@@ -1293,7 +1293,7 @@ void TorrentClient::schedulePieceForClient(PeerWireClient *client)
                 }
 
                 // Select one piece randomly
-                pieceIndex = piecesReadyForDownload.at(qrand() % piecesReadyForDownload.size());
+                pieceIndex = piecesReadyForDownload.at(QRandomGenerator::global()->bounded(piecesReadyForDownload.size()));
                 delete [] occurrences;
             } else {
                 // Make up a list of available piece indices, and pick
@@ -1304,7 +1304,7 @@ void TorrentClient::schedulePieceForClient(PeerWireClient *client)
                     if (incompletePiecesAvailableToClient.testBit(i))
                         values << i;
                 }
-                pieceIndex = values.at(qrand() % values.size());
+                pieceIndex = values.at(QRandomGenerator::global()->bounded(values.size()));
             }
 
             // Create a new TorrentPiece and fill in all initial
@@ -1396,8 +1396,8 @@ int TorrentClient::requestBlocks(PeerWireClient *client, TorrentPiece *piece, in
         // speedup comes from an increased chance of receiving
         // different blocks from the different peers.
         for (int i = 0; i < bits.size(); ++i) {
-            int a = qrand() % bits.size();
-            int b = qrand() % bits.size();
+            int a = QRandomGenerator::global()->bounded(bits.size());
+            int b = QRandomGenerator::global()->bounded(bits.size());
             int tmp = bits[a];
             bits[a] = bits[b];
             bits[b] = tmp;
diff --git a/examples/opengl/hellowindow/hellowindow.cpp b/examples/opengl/hellowindow/hellowindow.cpp
index 048190d766..a978e19b79 100644
--- a/examples/opengl/hellowindow/hellowindow.cpp
+++ b/examples/opengl/hellowindow/hellowindow.cpp
@@ -52,6 +52,7 @@
 
 #include <QOpenGLContext>
 #include <QOpenGLFunctions>
+#include <QRandomGenerator>
 #include <qmath.h>
 
 Renderer::Renderer(const QSurfaceFormat &format, Renderer *share, QScreen *screen)
@@ -68,9 +69,9 @@ Renderer::Renderer(const QSurfaceFormat &format, Renderer *share, QScreen *scree
     m_context->create();
 
     m_backgroundColor = QColor::fromRgbF(0.1f, 0.1f, 0.2f, 1.0f);
-    m_backgroundColor.setRed(qrand() % 64);
-    m_backgroundColor.setGreen(qrand() % 128);
-    m_backgroundColor.setBlue(qrand() % 256);
+    m_backgroundColor.setRed(QRandomGenerator::global()->bounded(64));
+    m_backgroundColor.setGreen(QRandomGenerator::global()->bounded(128));
+    m_backgroundColor.setBlue(QRandomGenerator::global()->bounded(256));
 }
 
 HelloWindow::HelloWindow(const QSharedPointer<Renderer> &renderer, QScreen *screen)
diff --git a/examples/opengl/legacy/overpainting/bubble.cpp b/examples/opengl/legacy/overpainting/bubble.cpp
index afc50117d0..352e359cf9 100644
--- a/examples/opengl/legacy/overpainting/bubble.cpp
+++ b/examples/opengl/legacy/overpainting/bubble.cpp
@@ -50,6 +50,8 @@
 
 #include "bubble.h"
 
+#include <QRandomGenerator>
+
 Bubble::Bubble(const QPointF &position, qreal radius, const QPointF &velocity)
     : position(position), vel(velocity), radius(radius)
 {
@@ -80,10 +82,10 @@ void Bubble::drawBubble(QPainter *painter)
 
 QColor Bubble::randomColor()
 {
-    int red = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int green = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int blue = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int alpha = int(91 + 100.0*qrand()/(RAND_MAX+1.0));
+    int red = int(205 + QRandomGenerator::global()->bounded(50));
+    int green = int(205 + QRandomGenerator::global()->bounded(50));
+    int blue = int(205 + QRandomGenerator::global()->bounded(50));
+    int alpha = int(91 + QRandomGenerator::global()->bounded(100));
 
     return QColor(red, green, blue, alpha);
 }
diff --git a/examples/opengl/legacy/overpainting/glwidget.cpp b/examples/opengl/legacy/overpainting/glwidget.cpp
index 7e9f4a5beb..1ec7bd731c 100644
--- a/examples/opengl/legacy/overpainting/glwidget.cpp
+++ b/examples/opengl/legacy/overpainting/glwidget.cpp
@@ -53,6 +53,7 @@
 #include "glwidget.h"
 
 #include <QMouseEvent>
+#include <QRandomGenerator>
 #include <QTime>
 
 #include <math.h>
@@ -67,7 +68,6 @@ GLWidget::GLWidget(QWidget *parent)
     : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
 {
     QTime midnight(0, 0, 0);
-    qsrand(midnight.secsTo(QTime::currentTime()));
 
     logo = 0;
     xRot = 0;
@@ -234,11 +234,11 @@ QSize GLWidget::sizeHint() const
 void GLWidget::createBubbles(int number)
 {
     for (int i = 0; i < number; ++i) {
-        QPointF position(width()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))),
-                        height()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))));
-        qreal radius = qMin(width(), height())*(0.0125 + 0.0875*qrand()/(RAND_MAX+1.0));
-        QPointF velocity(width()*0.0125*(-0.5 + qrand()/(RAND_MAX+1.0)),
-                        height()*0.0125*(-0.5 + qrand()/(RAND_MAX+1.0)));
+        QPointF position(width()*(0.1 + QRandomGenerator::global()->bounded(0.8)),
+                        height()*(0.1 + QRandomGenerator::global()->bounded(0.8)));
+        qreal radius = qMin(width(), height())*(0.0125 + QRandomGenerator::global()->bounded(0.0875));
+        QPointF velocity(width()*0.0125*(-0.5 + QRandomGenerator::global()->bounded(1.0)),
+                        height()*0.0125*(-0.5 + QRandomGenerator::global()->bounded(1.0)));
 
         bubbles.append(new Bubble(position, radius, velocity));
     }
diff --git a/examples/opengl/qopenglwidget/bubble.cpp b/examples/opengl/qopenglwidget/bubble.cpp
index adf5742f6a..dbaf460f6f 100644
--- a/examples/opengl/qopenglwidget/bubble.cpp
+++ b/examples/opengl/qopenglwidget/bubble.cpp
@@ -109,10 +109,10 @@ void Bubble::drawBubble(QPainter *painter)
 
 QColor Bubble::randomColor()
 {
-    int red = int(185 + 70.0*qrand()/(RAND_MAX+1.0));
-    int green = int(185 + 70.0*qrand()/(RAND_MAX+1.0));
-    int blue = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int alpha = int(91 + 100.0*qrand()/(RAND_MAX+1.0));
+    int red = int(185 + QRandomGenerator::global()->bounded(70));
+    int green = int(185 + QRandomGenerator::global()->bounded(70));
+    int blue = int(205 + QRandomGenerator::global()->bounded(50));
+    int alpha = int(91 + QRandomGenerator::global()->bounded(100));
 
     return QColor(red, green, blue, alpha);
 }
diff --git a/examples/opengl/qopenglwidget/glwidget.cpp b/examples/opengl/qopenglwidget/glwidget.cpp
index 40a1258dd5..3fe919f94b 100644
--- a/examples/opengl/qopenglwidget/glwidget.cpp
+++ b/examples/opengl/qopenglwidget/glwidget.cpp
@@ -53,6 +53,7 @@
 #include <QPaintEngine>
 #include <QOpenGLShaderProgram>
 #include <QOpenGLTexture>
+#include <QRandomGenerator>
 #include <QCoreApplication>
 #include <qmath.h>
 
@@ -420,11 +421,11 @@ void GLWidget::paintGL()
 void GLWidget::createBubbles(int number)
 {
     for (int i = 0; i < number; ++i) {
-        QPointF position(width()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))),
-                         height()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))));
-        qreal radius = qMin(width(), height())*(0.0175 + 0.0875*qrand()/(RAND_MAX+1.0));
-        QPointF velocity(width()*0.0175*(-0.5 + qrand()/(RAND_MAX+1.0)),
-                         height()*0.0175*(-0.5 + qrand()/(RAND_MAX+1.0)));
+        QPointF position(width()*(0.1 + QRandomGenerator::global()->bounded(0.8)),
+                         height()*(0.1 + QRandomGenerator::global()->bounded(0.8)));
+        qreal radius = qMin(width(), height())*(0.0175 + QRandomGenerator::global()->bounded(0.0875));
+        QPointF velocity(width()*0.0175*(-0.5 + QRandomGenerator::global()->bounded(1.0)),
+                         height()*0.0175*(-0.5 + QRandomGenerator::global()->bounded(1.0)));
 
         m_bubbles.append(new Bubble(position, radius, velocity));
     }
diff --git a/examples/opengl/qopenglwidget/mainwindow.cpp b/examples/opengl/qopenglwidget/mainwindow.cpp
index 1bb2aa2bf0..4bd123628f 100644
--- a/examples/opengl/qopenglwidget/mainwindow.cpp
+++ b/examples/opengl/qopenglwidget/mainwindow.cpp
@@ -56,6 +56,7 @@
 #include <QSlider>
 #include <QLabel>
 #include <QCheckBox>
+#include <QRandomGenerator>
 #include <QSpinBox>
 #include <QScrollArea>
 
@@ -155,7 +156,9 @@ void MainWindow::addNew()
 {
     if (m_nextY == 4)
         return;
-    GLWidget *w = new GLWidget(this, false, qRgb(qrand() % 256, qrand() % 256, qrand() % 256));
+    GLWidget *w = new GLWidget(this, false, qRgb(QRandomGenerator::global()->bounded(256),
+                                                 QRandomGenerator::global()->bounded(256),
+                                                 QRandomGenerator::global()->bounded(256)));
     m_glWidgets << w;
     connect(m_timer, &QTimer::timeout, w, QOverload<>::of(&QWidget::update));
     m_layout->addWidget(w, m_nextY, m_nextX, 1, 1);
diff --git a/examples/touch/pinchzoom/main.cpp b/examples/touch/pinchzoom/main.cpp
index 67099618c7..938432600f 100644
--- a/examples/touch/pinchzoom/main.cpp
+++ b/examples/touch/pinchzoom/main.cpp
@@ -61,7 +61,6 @@ static const int MouseCount = 7;
 int main(int argc, char **argv)
 {
     QApplication app(argc, argv);
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
 //! [0]
 
 //! [1]
diff --git a/examples/touch/pinchzoom/mouse.cpp b/examples/touch/pinchzoom/mouse.cpp
index 7f8c238e6f..1e6814be13 100644
--- a/examples/touch/pinchzoom/mouse.cpp
+++ b/examples/touch/pinchzoom/mouse.cpp
@@ -52,6 +52,7 @@
 
 #include <QGraphicsScene>
 #include <QPainter>
+#include <QRandomGenerator>
 #include <QStyleOption>
 #include <qmath.h>
 
@@ -70,9 +71,9 @@ static qreal normalizeAngle(qreal angle)
 //! [0]
 Mouse::Mouse()
     : angle(0), speed(0), mouseEyeDirection(0),
-      color(qrand() % 256, qrand() % 256, qrand() % 256)
+      color(QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256))
 {
-    setTransform(QTransform().rotate(qrand() % (360 * 16)), true);
+    setTransform(QTransform().rotate(QRandomGenerator::global()->bounded(360 * 16)), true);
     startTimer(1000 / 33);
 }
 //! [0]
@@ -184,16 +185,16 @@ void Mouse::timerEvent(QTimerEvent *)
 
     // Add some random movement
 //! [10]
-    if (dangerMice.size() > 1 && (qrand() % 10) == 0) {
-        if (qrand() % 1)
-            angle += (qrand() % 100) / 500.0;
+    if (dangerMice.size() > 1 && QRandomGenerator::global()->bounded(10) == 0) {
+        if (QRandomGenerator::global()->bounded(1))
+            angle += QRandomGenerator::global()->bounded(1 / 500.0);
         else
-            angle -= (qrand() % 100) / 500.0;
+            angle -= QRandomGenerator::global()->bounded(1 / 500.0);
     }
 //! [10]
 
 //! [11]
-    speed += (-50 + qrand() % 100) / 100.0;
+    speed += (-50 + QRandomGenerator::global()->bounded(100)) / 100.0;
 
     qreal dx = ::sin(angle) * 10;
     mouseEyeDirection = (qAbs(dx / 5) < 1) ? 0 : dx / 5;
diff --git a/examples/widgets/animation/animatedtiles/main.cpp b/examples/widgets/animation/animatedtiles/main.cpp
index 0511fe8162..89b5b67f8a 100644
--- a/examples/widgets/animation/animatedtiles/main.cpp
+++ b/examples/widgets/animation/animatedtiles/main.cpp
@@ -50,6 +50,7 @@
 
 #include <QtWidgets>
 #include <QtCore/qmath.h>
+#include <QtCore/qrandom.h>
 #include <QtCore/qstate.h>
 
 class Pixmap : public QObject, public QGraphicsPixmapItem
@@ -202,8 +203,8 @@ int main(int argc, char **argv)
 
         // Random
         randomState->assignProperty(item, "pos",
-                                        QPointF(-250 + qrand() % 500,
-                                                -250 + qrand() % 500));
+                                        QPointF(-250 + QRandomGenerator::global()->bounded(500),
+                                                -250 + QRandomGenerator::global()->bounded(500)));
 
         // Tiled
         tiledState->assignProperty(item, "pos",
diff --git a/examples/widgets/animation/moveblocks/main.cpp b/examples/widgets/animation/moveblocks/main.cpp
index a9b95808a5..6d17696108 100644
--- a/examples/widgets/animation/moveblocks/main.cpp
+++ b/examples/widgets/animation/moveblocks/main.cpp
@@ -125,7 +125,7 @@ public:
     void onEntry(QEvent *) override
     {
         int n;
-        while ((n = (qrand() % m_stateCount + 1)) == m_lastIndex)
+        while ((n = QRandomGenerator::global()->bounded(m_stateCount) + 1) == m_lastIndex)
         { }
         m_lastIndex = n;
         machine()->postEvent(new StateSwitchEvent(n));
@@ -323,8 +323,6 @@ int main(int argc, char **argv)
     window.resize(300, 300);
     window.show();
 
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
-
     return app.exec();
 }
 
diff --git a/examples/widgets/animation/stickman/lifecycle.cpp b/examples/widgets/animation/stickman/lifecycle.cpp
index 253af22b2d..dbe9a299b4 100644
--- a/examples/widgets/animation/stickman/lifecycle.cpp
+++ b/examples/widgets/animation/stickman/lifecycle.cpp
@@ -91,13 +91,12 @@ public:
         : QEventTransition(this, QEvent::Timer)
     {
         setTargetState(target);
-        qsrand((uint)QDateTime::currentSecsSinceEpoch());
         startTimer(1000);
     }
 
     bool eventTest(QEvent *e) override
     {
-        return QEventTransition::eventTest(e) && ((qrand() % 50) == 0);
+        return QEventTransition::eventTest(e) && QRandomGenerator::global()->bounded(50) == 0;
     }
 };
 //! [4]
diff --git a/examples/widgets/animation/sub-attaq/main.cpp b/examples/widgets/animation/sub-attaq/main.cpp
index f65ca7be18..9b28d8c40f 100644
--- a/examples/widgets/animation/sub-attaq/main.cpp
+++ b/examples/widgets/animation/sub-attaq/main.cpp
@@ -57,8 +57,6 @@ int main(int argc, char *argv[])
     QApplication app(argc, argv);
     Q_INIT_RESOURCE(subattaq);
 
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
-
     MainWindow w;
     w.show();
 
diff --git a/examples/widgets/animation/sub-attaq/states.cpp b/examples/widgets/animation/sub-attaq/states.cpp
index 21cff048e7..e19704db7b 100644
--- a/examples/widgets/animation/sub-attaq/states.cpp
+++ b/examples/widgets/animation/sub-attaq/states.cpp
@@ -64,6 +64,7 @@
 #include <QtCore/QStateMachine>
 #include <QtWidgets/QKeyEventTransition>
 #include <QtCore/QFinalState>
+#include <QtCore/QRandomGenerator>
 
 PlayState::PlayState(GraphicsScene *scene, QState *parent)
     : QState(parent),
@@ -193,12 +194,12 @@ void LevelState::initializeLevel()
         for (int j = 0; j < subContent.second; ++j ) {
             SubMarine *sub = new SubMarine(submarineDesc.type, submarineDesc.name, submarineDesc.points);
             scene->addItem(sub);
-            int random = (qrand() % 15 + 1);
+            int random = QRandomGenerator::global()->bounded(15) + 1;
             qreal x = random == 13 || random == 5 ? 0 : scene->width() - sub->size().width();
-            qreal y = scene->height() -(qrand() % 150 + 1) - sub->size().height();
+            qreal y = scene->height() -(QRandomGenerator::global()->bounded(150) + 1) - sub->size().height();
             sub->setPos(x,y);
             sub->setCurrentDirection(x == 0 ? SubMarine::Right : SubMarine::Left);
-            sub->setCurrentSpeed(qrand() % 3 + 1);
+            sub->setCurrentSpeed(QRandomGenerator::global()->bounded(3) + 1);
         }
     }
 }
diff --git a/examples/widgets/animation/sub-attaq/submarine_p.h b/examples/widgets/animation/sub-attaq/submarine_p.h
index b8d5532962..698b4b494f 100644
--- a/examples/widgets/animation/sub-attaq/submarine_p.h
+++ b/examples/widgets/animation/sub-attaq/submarine_p.h
@@ -69,6 +69,7 @@
 
 //Qt
 #include <QtCore/QPropertyAnimation>
+#include <QtCore/QRandomGenerator>
 #include <QtWidgets/QGraphicsScene>
 
 //This state is describing when the boat is moving right
@@ -88,8 +89,8 @@ public:
 protected slots:
     void onAnimationMovementValueChanged(const QVariant &)
     {
-        if (qrand() % 200 + 1 == 3)
-            submarine->launchTorpedo(qrand() % 3 + 1);
+        if (QRandomGenerator::global()->bounded(200) + 1 == 3)
+            submarine->launchTorpedo(QRandomGenerator::global()->bounded(3) + 1);
     }
 
 protected:
diff --git a/examples/widgets/doc/src/collidingmice-example.qdoc b/examples/widgets/doc/src/collidingmice-example.qdoc
index 02417ba521..535057bb6a 100644
--- a/examples/widgets/doc/src/collidingmice-example.qdoc
+++ b/examples/widgets/doc/src/collidingmice-example.qdoc
@@ -80,8 +80,7 @@
     \snippet graphicsview/collidingmice/mouse.cpp 0
 
     To calculate the various components of the mouse's color, we use
-    the global qrand() function which is a thread-safe version of the
-    standard C++ rand() function.
+    \l QRandomGenerator.
 
     Then we call the \l {QGraphicsItem::setRotation()}{setRotation()} function
     inherited from QGraphicsItem. Items live in their own local
@@ -178,12 +177,7 @@
 
     \snippet graphicsview/collidingmice/main.cpp 0
 
-    First, we create an application object and call the global
-    qsrand() function to specify the seed used to generate a new
-    random number sequence of pseudo random integers with the
-    previously mentioned qrand() function.
-
-    Then it is time to create the scene:
+    First, we create an application object and create the scene:
 
     \snippet graphicsview/collidingmice/main.cpp 1
 
diff --git a/examples/widgets/doc/src/dragdroprobot.qdoc b/examples/widgets/doc/src/dragdroprobot.qdoc
index ac221ec5f9..f74b898e1b 100644
--- a/examples/widgets/doc/src/dragdroprobot.qdoc
+++ b/examples/widgets/doc/src/dragdroprobot.qdoc
@@ -257,7 +257,7 @@
     \snippet graphicsview/dragdroprobot/coloritem.cpp 0
 
     \c ColorItem's constructor assigns an opaque random color to its color
-    member by making use of qrand(). For improved usability, it assigns a
+    member by making use of \l QRandomGenerator. For improved usability, it assigns a
     tooltip that provides a useful hint to the user, and it also sets a
     suitable cursor. This ensures that the cursor will chance to
     Qt::OpenHandCursor when the mouse pointer hovers over the item.
diff --git a/examples/widgets/doc/src/elasticnodes.qdoc b/examples/widgets/doc/src/elasticnodes.qdoc
index 09ac891b24..65e1195121 100644
--- a/examples/widgets/doc/src/elasticnodes.qdoc
+++ b/examples/widgets/doc/src/elasticnodes.qdoc
@@ -424,9 +424,8 @@
     \section1 The main() Function
 
     In contrast to the complexity of the rest of this example, the \c main()
-    function is very simple: We create a QApplication instance, seed the
-    randomizer using qsrand(), and then create and show an instance of \c
-    GraphWidget. Because all nodes in the grid are moved initially, the \c
-    GraphWidget timer will start immediately after control has returned to the
-    event loop.
+    function is very simple: We create a QApplication instance, then create and
+    show an instance of \c GraphWidget. Because all nodes in the grid are moved
+    initially, the \c GraphWidget timer will start immediately after control
+    has returned to the event loop.
 */
diff --git a/examples/widgets/draganddrop/puzzle/mainwindow.cpp b/examples/widgets/draganddrop/puzzle/mainwindow.cpp
index 1914519c68..98a7cd4265 100644
--- a/examples/widgets/draganddrop/puzzle/mainwindow.cpp
+++ b/examples/widgets/draganddrop/puzzle/mainwindow.cpp
@@ -122,10 +122,8 @@ void MainWindow::setupPuzzle()
         }
     }
 
-    qsrand(QCursor::pos().x() ^ QCursor::pos().y());
-
     for (int i = 0; i < piecesList->count(); ++i) {
-        if (int(2.0*qrand()/(RAND_MAX+1.0)) == 1) {
+        if (QRandomGenerator::global()->bounded(2) == 1) {
             QListWidgetItem *item = piecesList->takeItem(i);
             piecesList->insertItem(0, item);
         }
diff --git a/examples/widgets/graphicsview/boxes/qtbox.cpp b/examples/widgets/graphicsview/boxes/qtbox.cpp
index 9a19985fac..3a184dd0b6 100644
--- a/examples/widgets/graphicsview/boxes/qtbox.cpp
+++ b/examples/widgets/graphicsview/boxes/qtbox.cpp
@@ -414,7 +414,7 @@ void QtBox::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWi
 
 CircleItem::CircleItem(int size, int x, int y) : ItemBase(size, x, y)
 {
-     m_color = QColor::fromHsv(rand() % 360, 255, 255);
+     m_color = QColor::fromHsv(QRandomGenerator::global()->bounded(360), 255, 255);
 }
 
 void CircleItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
diff --git a/examples/widgets/graphicsview/boxes/scene.cpp b/examples/widgets/graphicsview/boxes/scene.cpp
index 31b9553c75..f51cad99ac 100644
--- a/examples/widgets/graphicsview/boxes/scene.cpp
+++ b/examples/widgets/graphicsview/boxes/scene.cpp
@@ -50,6 +50,7 @@
 
 #include <QDebug>
 #include "scene.h"
+#include <QtCore/QRandomGenerator>
 #include <QtGui/qmatrix4x4.h>
 #include <QtGui/qvector3d.h>
 #include <qmath.h>
@@ -1072,13 +1073,16 @@ void Scene::newItem(ItemDialog::ItemType type)
     QSize size = sceneRect().size().toSize();
     switch (type) {
     case ItemDialog::QtBoxItem:
-        addItem(new QtBox(64, rand() % (size.width() - 64) + 32, rand() % (size.height() - 64) + 32));
+        addItem(new QtBox(64, QRandomGenerator::global()->bounded(size.width() - 64) + 32,
+                          QRandomGenerator::global()->bounded(size.height() - 64) + 32));
         break;
     case ItemDialog::CircleItem:
-        addItem(new CircleItem(64, rand() % (size.width() - 64) + 32, rand() % (size.height() - 64) + 32));
+        addItem(new CircleItem(64, QRandomGenerator::global()->bounded(size.width() - 64) + 32,
+                               QRandomGenerator::global()->bounded(size.height() - 64) + 32));
         break;
     case ItemDialog::SquareItem:
-        addItem(new SquareItem(64, rand() % (size.width() - 64) + 32, rand() % (size.height() - 64) + 32));
+        addItem(new SquareItem(64, QRandomGenerator::global()->bounded(size.width() - 64) + 32,
+                               QRandomGenerator::global()->bounded(size.height() - 64) + 32));
         break;
     default:
         break;
diff --git a/examples/widgets/graphicsview/collidingmice/main.cpp b/examples/widgets/graphicsview/collidingmice/main.cpp
index a0659b9bc1..91aee70b86 100644
--- a/examples/widgets/graphicsview/collidingmice/main.cpp
+++ b/examples/widgets/graphicsview/collidingmice/main.cpp
@@ -60,7 +60,6 @@ static const int MouseCount = 7;
 int main(int argc, char **argv)
 {
     QApplication app(argc, argv);
-    qsrand(QTime(0, 0, 0).secsTo(QTime::currentTime()));
 //! [0]
 
 //! [1]
diff --git a/examples/widgets/graphicsview/collidingmice/mouse.cpp b/examples/widgets/graphicsview/collidingmice/mouse.cpp
index 298e4aae64..14f887f6e3 100644
--- a/examples/widgets/graphicsview/collidingmice/mouse.cpp
+++ b/examples/widgets/graphicsview/collidingmice/mouse.cpp
@@ -52,6 +52,7 @@
 
 #include <QGraphicsScene>
 #include <QPainter>
+#include <QRandomGenerator>
 #include <QStyleOption>
 #include <qmath.h>
 
@@ -70,9 +71,9 @@ static qreal normalizeAngle(qreal angle)
 //! [0]
 Mouse::Mouse()
     : angle(0), speed(0), mouseEyeDirection(0),
-      color(qrand() % 256, qrand() % 256, qrand() % 256)
+      color(QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256))
 {
-    setRotation(qrand() % (360 * 16));
+    setRotation(QRandomGenerator::global()->bounded(360 * 16));
 }
 //! [0]
 
@@ -185,16 +186,16 @@ void Mouse::advance(int step)
 
     // Add some random movement
 //! [10]
-    if (dangerMice.size() > 1 && (qrand() % 10) == 0) {
-        if (qrand() % 1)
-            angle += (qrand() % 100) / 500.0;
+    if (dangerMice.size() > 1 && QRandomGenerator::global()->bounded(10) == 0) {
+        if (QRandomGenerator::global()->bounded(1))
+            angle += QRandomGenerator::global()->bounded(1 / 500.0);
         else
-            angle -= (qrand() % 100) / 500.0;
+            angle -= QRandomGenerator::global()->bounded(1 / 500.0);
     }
 //! [10]
 
 //! [11]
-    speed += (-50 + qrand() % 100) / 100.0;
+    speed += (-50 + QRandomGenerator::global()->bounded(100)) / 100.0;
 
     qreal dx = ::sin(angle) * 10;
     mouseEyeDirection = (qAbs(dx / 5) < 1) ? 0 : dx / 5;
diff --git a/examples/widgets/graphicsview/dragdroprobot/coloritem.cpp b/examples/widgets/graphicsview/dragdroprobot/coloritem.cpp
index 64a715d31f..262e18a317 100644
--- a/examples/widgets/graphicsview/dragdroprobot/coloritem.cpp
+++ b/examples/widgets/graphicsview/dragdroprobot/coloritem.cpp
@@ -54,7 +54,7 @@
 
 //! [0]
 ColorItem::ColorItem()
-    : color(qrand() % 256, qrand() % 256, qrand() % 256)
+    : color(QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256))
 {
     setToolTip(QString("QColor(%1, %2, %3)\n%4")
               .arg(color.red()).arg(color.green()).arg(color.blue())
@@ -107,7 +107,7 @@ void ColorItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
 
 //! [6]
     static int n = 0;
-    if (n++ > 2 && (qrand() % 3) == 0) {
+    if (n++ > 2 && QRandomGenerator::global()->bounded(3) == 0) {
         QImage image(":/images/head.png");
         mime->setImageData(image);
 
diff --git a/examples/widgets/graphicsview/dragdroprobot/main.cpp b/examples/widgets/graphicsview/dragdroprobot/main.cpp
index 20cec92d26..045e184569 100644
--- a/examples/widgets/graphicsview/dragdroprobot/main.cpp
+++ b/examples/widgets/graphicsview/dragdroprobot/main.cpp
@@ -73,7 +73,6 @@ int main(int argc, char **argv)
 {
     QApplication app(argc, argv);
 
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
 //! [0]
 //! [1]
     QGraphicsScene scene(-200, -200, 400, 400);
diff --git a/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp b/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp
index 844c8f8aac..4259aab803 100644
--- a/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp
+++ b/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp
@@ -55,6 +55,7 @@
 #include <math.h>
 
 #include <QKeyEvent>
+#include <QRandomGenerator>
 
 //! [0]
 GraphWidget::GraphWidget(QWidget *parent)
@@ -247,7 +248,7 @@ void GraphWidget::shuffle()
 {
     foreach (QGraphicsItem *item, scene()->items()) {
         if (qgraphicsitem_cast<Node *>(item))
-            item->setPos(-150 + qrand() % 300, -150 + qrand() % 300);
+            item->setPos(-150 + QRandomGenerator::global()->bounded(300), -150 + QRandomGenerator::global()->bounded(300));
     }
 }
 
diff --git a/examples/widgets/graphicsview/elasticnodes/main.cpp b/examples/widgets/graphicsview/elasticnodes/main.cpp
index 75cc4b0f69..1e372a9f6d 100644
--- a/examples/widgets/graphicsview/elasticnodes/main.cpp
+++ b/examples/widgets/graphicsview/elasticnodes/main.cpp
@@ -57,7 +57,6 @@
 int main(int argc, char **argv)
 {
     QApplication app(argc, argv);
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
 
     GraphWidget *widget = new GraphWidget;
 
diff --git a/examples/widgets/itemviews/puzzle/mainwindow.cpp b/examples/widgets/itemviews/puzzle/mainwindow.cpp
index 8ee5cf659e..d598dc9017 100644
--- a/examples/widgets/itemviews/puzzle/mainwindow.cpp
+++ b/examples/widgets/itemviews/puzzle/mainwindow.cpp
@@ -114,8 +114,6 @@ void MainWindow::setupPuzzle()
         (puzzleImage.height() - size) / 2, size, size).scaled(puzzleWidget->imageSize(),
             puzzleWidget->imageSize(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
 
-    qsrand(QCursor::pos().x() ^ QCursor::pos().y());
-
     model->addPieces(puzzleImage);
     puzzleWidget->clear();
 }
diff --git a/examples/widgets/itemviews/puzzle/piecesmodel.cpp b/examples/widgets/itemviews/puzzle/piecesmodel.cpp
index 0fbf0cdcc2..f0649d3776 100644
--- a/examples/widgets/itemviews/puzzle/piecesmodel.cpp
+++ b/examples/widgets/itemviews/puzzle/piecesmodel.cpp
@@ -52,6 +52,7 @@
 
 #include <QIcon>
 #include <QMimeData>
+#include <QRandomGenerator>
 
 PiecesModel::PiecesModel(int pieceSize, QObject *parent)
     : QAbstractListModel(parent), m_PieceSize(pieceSize)
@@ -77,7 +78,7 @@ QVariant PiecesModel::data(const QModelIndex &index, int role) const
 void PiecesModel::addPiece(const QPixmap &pixmap, const QPoint &location)
 {
     int row;
-    if (int(2.0 * qrand() / (RAND_MAX + 1.0)) == 1)
+    if (QRandomGenerator::global()->bounded(2) == 1)
         row = 0;
     else
         row = pixmaps.size();
diff --git a/examples/widgets/mainwindows/mainwindow/toolbar.cpp b/examples/widgets/mainwindows/mainwindow/toolbar.cpp
index 97152a64a3..814cfc7f4d 100644
--- a/examples/widgets/mainwindows/mainwindow/toolbar.cpp
+++ b/examples/widgets/mainwindows/mainwindow/toolbar.cpp
@@ -50,6 +50,8 @@
 
 #include "toolbar.h"
 
+#include <QRandomGenerator>
+
 #include <QMainWindow>
 #include <QMenu>
 #include <QPainter>
@@ -257,7 +259,7 @@ void ToolBar::randomize()
     QList<QAction *> randomized;
     QList<QAction *> actions = this->actions();
     while (!actions.isEmpty()) {
-        QAction *action = actions.takeAt(rand() % actions.size());
+        QAction *action = actions.takeAt(QRandomGenerator::global()->bounded(actions.size()));
         randomized.append(action);
     }
     clear();
diff --git a/examples/widgets/statemachine/rogue/window.cpp b/examples/widgets/statemachine/rogue/window.cpp
index 428d4c3af6..3515138382 100644
--- a/examples/widgets/statemachine/rogue/window.cpp
+++ b/examples/widgets/statemachine/rogue/window.cpp
@@ -248,11 +248,9 @@ void Window::movePlayer(Direction direction)
 
 void Window::setupMap()
 {
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
-
     for (int x = 0; x < WIDTH; ++x)
         for (int y = 0; y < HEIGHT; ++y) {
-        if (x == 0 || x == WIDTH - 1 || y == 0 || y == HEIGHT - 1 || qrand() % 40 == 0)
+        if (x == 0 || x == WIDTH - 1 || y == 0 || y == HEIGHT - 1 || QRandomGenerator::global()->bounded(40) == 0)
             map[x][y] = '#';
         else
             map[x][y] = '.';
diff --git a/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp b/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp
index 740d007d44..92620ddd8c 100644
--- a/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp
+++ b/examples/widgets/tools/plugandpaint/plugins/basictools/basictoolsplugin.cpp
@@ -101,7 +101,7 @@ QRect BasicToolsPlugin::mouseMove(const QString &brush, QPainter &painter,
                                 thickness, thickness);
         }
     } else if (brush == tr("Random Letters")) {
-        QChar ch('A' + (qrand() % 26));
+        QChar ch(QRandomGenerator::global()->bounded('A', 'Z' + 1));
 
         QFont biggerFont = painter.font();
         biggerFont.setBold(true);
diff --git a/examples/widgets/tools/undo/mainwindow.cpp b/examples/widgets/tools/undo/mainwindow.cpp
index aa570caa80..5976163f3f 100644
--- a/examples/widgets/tools/undo/mainwindow.cpp
+++ b/examples/widgets/tools/undo/mainwindow.cpp
@@ -52,6 +52,7 @@
 #include <QUndoStack>
 #include <QFileDialog>
 #include <QMessageBox>
+#include <QRandomGenerator>
 #include <QTextStream>
 #include <QToolButton>
 #include "document.h"
@@ -321,7 +322,7 @@ void MainWindow::newDocument()
 
 static QColor randomColor()
 {
-    int r = (int) (3.0*(rand()/(RAND_MAX + 1.0)));
+    int r = QRandomGenerator::global()->bounded(3);
     switch (r) {
         case 0:
             return Qt::red;
@@ -337,10 +338,10 @@ static QRect randomRect(const QSize &s)
 {
     QSize min = Shape::minSize;
 
-    int left = (int) ((0.0 + s.width() - min.width())*(rand()/(RAND_MAX + 1.0)));
-    int top = (int) ((0.0 + s.height() - min.height())*(rand()/(RAND_MAX + 1.0)));
-    int width = (int) ((0.0 + s.width() - left - min.width())*(rand()/(RAND_MAX + 1.0))) + min.width();
-    int height = (int) ((0.0 + s.height() - top - min.height())*(rand()/(RAND_MAX + 1.0))) + min.height();
+    int left = (int) ((0.0 + s.width() - min.width())*(QRandomGenerator::global()->bounded(1.0)));
+    int top = (int) ((0.0 + s.height() - min.height())*(QRandomGenerator::global()->bounded(1.0)));
+    int width = (int) ((0.0 + s.width() - left - min.width())*(QRandomGenerator::global()->bounded(1.0))) + min.width();
+    int height = (int) ((0.0 + s.height() - top - min.height())*(QRandomGenerator::global()->bounded(1.0))) + min.height();
 
     return QRect(left, top, width, height);
 }
diff --git a/examples/widgets/tools/undoframework/diagramitem.cpp b/examples/widgets/tools/undoframework/diagramitem.cpp
index 754baa2377..723645c9b2 100644
--- a/examples/widgets/tools/undoframework/diagramitem.cpp
+++ b/examples/widgets/tools/undoframework/diagramitem.cpp
@@ -65,8 +65,7 @@ DiagramItem::DiagramItem(DiagramType diagramType, QGraphicsItem *item)
         setPolygon(trianglePolygon);
     }
 
-    QColor color(static_cast<int>(qrand()) % 256,
-        static_cast<int>(qrand()) % 256, static_cast<int>(qrand()) % 256);
+    QColor color(QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256), QRandomGenerator::global()->bounded(256));
     QBrush brush(color);
     setBrush(brush);
     setFlag(QGraphicsItem::ItemIsSelectable);
diff --git a/examples/widgets/widgets/tetrix/main.cpp b/examples/widgets/widgets/tetrix/main.cpp
index 886e94de7c..2698190e76 100644
--- a/examples/widgets/widgets/tetrix/main.cpp
+++ b/examples/widgets/widgets/tetrix/main.cpp
@@ -59,6 +59,5 @@ int main(int argc, char *argv[])
     QApplication app(argc, argv);
     TetrixWindow window;
     window.show();
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
     return app.exec();
 }
diff --git a/examples/widgets/widgets/tetrix/tetrixpiece.cpp b/examples/widgets/widgets/tetrix/tetrixpiece.cpp
index 69e1733ac4..3d8fa86860 100644
--- a/examples/widgets/widgets/tetrix/tetrixpiece.cpp
+++ b/examples/widgets/widgets/tetrix/tetrixpiece.cpp
@@ -57,7 +57,7 @@
 //! [0]
 void TetrixPiece::setRandomShape()
 {
-    setShape(TetrixShape(qrand() % 7 + 1));
+    setShape(TetrixShape(QRandomGenerator::global()->bounded(7) + 1));
 }
 //! [0]
 
diff --git a/examples/widgets/widgets/tooltips/main.cpp b/examples/widgets/widgets/tooltips/main.cpp
index 3c64a33a4c..8276b3dc8d 100644
--- a/examples/widgets/widgets/tooltips/main.cpp
+++ b/examples/widgets/widgets/tooltips/main.cpp
@@ -57,7 +57,6 @@ int main(int argc, char *argv[])
     Q_INIT_RESOURCE(tooltips);
 
     QApplication app(argc, argv);
-    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
     SortingBox sortingBox;
     sortingBox.show();
     return app.exec();
diff --git a/examples/widgets/widgets/tooltips/sortingbox.cpp b/examples/widgets/widgets/tooltips/sortingbox.cpp
index c15fdcf95b..4769a30c64 100644
--- a/examples/widgets/widgets/tooltips/sortingbox.cpp
+++ b/examples/widgets/widgets/tooltips/sortingbox.cpp
@@ -292,7 +292,7 @@ QPoint SortingBox::initialItemPosition(const QPainterPath &path)
 //! [24]
 QPoint SortingBox::randomItemPosition()
 {
-    return QPoint(qrand() % (width() - 120), qrand() % (height() - 120));
+    return QPoint(QRandomGenerator::global()->bounded(width() - 120), QRandomGenerator::global()->bounded(height() - 120));
 }
 //! [24]
 
@@ -306,6 +306,6 @@ QColor SortingBox::initialItemColor()
 //! [26]
 QColor SortingBox::randomItemColor()
 {
-    return QColor::fromHsv(qrand() % 256, 255, 190);
+    return QColor::fromHsv(QRandomGenerator::global()->bounded(256), 255, 190);
 }
 //! [26]