QtBase: use printf-style qWarning/qDebug where possible (II)

The printf-style version of QDebug expands to a lot less code than the
std::ostream-style version. Of course, you pay in type safety (but
compilers warn about it these days), you cannot stream complex Qt
types and streaming QStrings is awkward, but in many cases you
actually improve on readability.

But the main reason is that something that's not supposed to be
executed under normal operation has no business bloating executable
code size.

This is not an attempt at converting all qWarnings() to printf-style,
only the low-hanging fruit.

In this second part, replace
   qWarning() << "" << non-QString
with
   qWarning("..%.", non-QString).

QString (and QUrl etc) have special escaping handling when streamed
into QDebug, so leave those alone. They also seem to expand to less
code than the qPrintable() alternative, so there's no reason to
replace them.

Saves 2KiB, 3.4KiB, ~750b and ~450b in text size in QtCore, Gui,
Network and Widgets, resp., on optimized GCC 5.3 AMD64 builds.

Change-Id: Iae6823e543544347e628ca1060d6d51e3b04d3f4
Reviewed-by: Kai Koehne <kai.koehne@qt.io>

26 files changed, 81 insertions, 77 deletions

diff --git a/src/corelib/codecs/qicucodec.cpp b/src/corelib/codecs/qicucodec.cpp
index aa2095d9da..ee9f1d0048 100644
--- a/src/corelib/codecs/qicucodec.cpp
+++ b/src/corelib/codecs/qicucodec.cpp
@@ -527,7 +527,7 @@ QTextCodec *QIcuCodec::codecForNameUnlocked(const char *name)
     // check whether there is really a converter for the name available.
     UConverter *conv = ucnv_open(standardName, &error);
     if (!conv) {
-        qDebug() << "codecForName: ucnv_open failed" << standardName << u_errorName(error);
+        qDebug("codecForName: ucnv_open failed %s %s", standardName, u_errorName(error));
         return 0;
     }
     //qDebug() << "QIcuCodec: Standard name for " << name << "is" << standardName;
@@ -577,7 +577,7 @@ UConverter *QIcuCodec::getConverter(QTextCodec::ConverterState *state) const
             ucnv_setSubstChars(static_cast<UConverter *>(state->d),
                                state->flags & QTextCodec::ConvertInvalidToNull ? "\0" : "?", 1, &error);
             if (U_FAILURE(error))
-                qDebug() << "getConverter(state) ucnv_open failed" << m_name << u_errorName(error);
+                qDebug("getConverter(state) ucnv_open failed %s %s", m_name, u_errorName(error));
         }
         conv = static_cast<UConverter *>(state->d);
     }
@@ -587,7 +587,7 @@ UConverter *QIcuCodec::getConverter(QTextCodec::ConverterState *state) const
         conv = ucnv_open(m_name, &error);
         ucnv_setSubstChars(conv, "?", 1, &error);
         if (U_FAILURE(error))
-            qDebug() << "getConverter(no state) ucnv_open failed" << m_name << u_errorName(error);
+            qDebug("getConverter(no state) ucnv_open failed %s %s", m_name, u_errorName(error));
     }
     return conv;
 }
@@ -610,7 +610,7 @@ QString QIcuCodec::convertToUnicode(const char *chars, int length, QTextCodec::C
                        &chars, end,
                        0, false, &error);
         if (!U_SUCCESS(error) && error != U_BUFFER_OVERFLOW_ERROR) {
-            qDebug() << "convertToUnicode failed:" << u_errorName(error);
+            qDebug("convertToUnicode failed: %s", u_errorName(error));
             break;
         }
 
@@ -647,7 +647,7 @@ QByteArray QIcuCodec::convertFromUnicode(const QChar *unicode, int length, QText
                          &uc, end,
                          0, false, &error);
         if (!U_SUCCESS(error))
-            qDebug() << "convertFromUnicode failed:" << u_errorName(error);
+            qDebug("convertFromUnicode failed: %s", u_errorName(error));
         convertedChars = ch - string.data();
         if (uc >= end)
             break;
diff --git a/src/corelib/io/qfsfileengine.cpp b/src/corelib/io/qfsfileengine.cpp
index 7a04939cdb..098bc49468 100644
--- a/src/corelib/io/qfsfileengine.cpp
+++ b/src/corelib/io/qfsfileengine.cpp
@@ -545,7 +545,7 @@ bool QFSFileEnginePrivate::seekFdFh(qint64 pos)
     } else {
         // Unbuffered stdio mode.
         if (QT_LSEEK(fd, QT_OFF_T(pos), SEEK_SET) == -1) {
-            qWarning() << "QFile::at: Cannot set file position" << pos;
+            qWarning("QFile::at: Cannot set file position %lld", pos);
             q->setError(QFile::PositionError, qt_error_string(errno));
             return false;
         }
diff --git a/src/corelib/io/qlockfile_win.cpp b/src/corelib/io/qlockfile_win.cpp
index 261363f320..ba4a091965 100644
--- a/src/corelib/io/qlockfile_win.cpp
+++ b/src/corelib/io/qlockfile_win.cpp
@@ -100,7 +100,7 @@ QLockFile::LockError QLockFilePrivate::tryLock_sys()
                 ? QLockFile::LockFailedError
                 : QLockFile::PermissionError;
         default:
-            qWarning() << "Got unexpected locking error" << lastError;
+            qWarning("Got unexpected locking error %llu", quint64(lastError));
             return QLockFile::UnknownError;
         }
     }
diff --git a/src/corelib/kernel/qppsobject.cpp b/src/corelib/kernel/qppsobject.cpp
index dbff997c88..f716c1a92e 100644
--- a/src/corelib/kernel/qppsobject.cpp
+++ b/src/corelib/kernel/qppsobject.cpp
@@ -397,12 +397,12 @@ QByteArray QPpsObjectPrivate::encode(const QVariantMap &ppsData, bool *ok)
 void QPpsObjectPrivate::encodeData(pps_encoder_t *encoder, const char *name, const QVariant &data,
                                    bool *ok)
 {
-    QString errorFunction;
+    const char *errorFunction;
     pps_encoder_error_t error = PPS_ENCODER_OK;
     switch (data.type()) {
     case QVariant::Bool:
         error = pps_encoder_add_bool(encoder, name, data.toBool());
-        errorFunction = QStringLiteral("pps_encoder_add_bool");
+        errorFunction = "pps_encoder_add_bool";
         break;
     // We want to support encoding uint even though libpps doesn't support it directly.
     // We can't encode uint as an int since that will lose precision (e.g. 2^31+1 can't be
@@ -411,41 +411,41 @@ void QPpsObjectPrivate::encodeData(pps_encoder_t *encoder, const char *name, con
     case QVariant::UInt:
     case QVariant::Double:
         error = pps_encoder_add_double(encoder, name, data.toDouble());
-        errorFunction = QStringLiteral("pps_encoder_add_double");
+        errorFunction = "pps_encoder_add_double";
         break;
     case QVariant::Int:
         error = pps_encoder_add_int(encoder, name, data.toInt());
-        errorFunction = QStringLiteral("pps_encoder_add_int");
+        errorFunction = "pps_encoder_add_int";
         break;
     case QVariant::LongLong:
         error = pps_encoder_add_int64(encoder, name, data.toLongLong());
-        errorFunction = QStringLiteral("pps_encoder_add_int64");
+        errorFunction = "pps_encoder_add_int64";
         break;
     case QVariant::String:
         error = pps_encoder_add_string(encoder, name, data.toString().toUtf8().constData());
-        errorFunction = QStringLiteral("pps_encoder_add_string");
+        errorFunction = "pps_encoder_add_string";
         break;
     case QVariant::List:
         error = pps_encoder_start_array(encoder, name);
-        errorFunction = QStringLiteral("pps_encoder_start_array");
+        errorFunction = "pps_encoder_start_array";
         if (error == PPS_ENCODER_OK) {
             encodeArray(encoder, data.toList(), ok);
             error = pps_encoder_end_array(encoder);
-            errorFunction = QStringLiteral("pps_encoder_end_array");
+            errorFunction = "pps_encoder_end_array";
         }
         break;
     case QVariant::Map:
         error = pps_encoder_start_object(encoder, name);
-        errorFunction = QStringLiteral("pps_encoder_start_object");
+        errorFunction = "pps_encoder_start_object";
         if (error == PPS_ENCODER_OK) {
             encodeObject(encoder, data.toMap(), ok);
             error = pps_encoder_end_object(encoder);
-            errorFunction = QStringLiteral("pps_encoder_end_object");
+            errorFunction = "pps_encoder_end_object";
         }
         break;
     case QVariant::Invalid:
         error = pps_encoder_add_null(encoder, name);
-        errorFunction = QStringLiteral("pps_encoder_add_null");
+        errorFunction = "pps_encoder_add_null";
         break;
     default:
         qWarning("QPpsObjectPrivate::encodeData: the type of the parameter data is invalid");
@@ -454,7 +454,7 @@ void QPpsObjectPrivate::encodeData(pps_encoder_t *encoder, const char *name, con
     }
 
     if (error != PPS_ENCODER_OK) {
-        qWarning() << "QPpsObjectPrivate::encodeData: " << errorFunction << " failed";
+        qWarning("QPpsObjectPrivate::encodeData: %s failed", errorFunction);
         *ok = false;
     } else {
         *ok = true;
diff --git a/src/corelib/kernel/qsystemsemaphore_posix.cpp b/src/corelib/kernel/qsystemsemaphore_posix.cpp
index 6137239467..9fbf5779b8 100644
--- a/src/corelib/kernel/qsystemsemaphore_posix.cpp
+++ b/src/corelib/kernel/qsystemsemaphore_posix.cpp
@@ -147,7 +147,7 @@ bool QSystemSemaphorePrivate::modifySemaphore(int count)
             if (::sem_post(semaphore) == -1) {
                 setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore (sem_post)"));
 #if defined QSYSTEMSEMAPHORE_DEBUG
-                qDebug() << QLatin1String("QSystemSemaphore::modify sem_post failed") << count << errno;
+                qDebug("QSystemSemaphore::modify sem_post failed %d %d", count, errno);
 #endif
                 // rollback changes to preserve the SysV semaphore behavior
                 for ( ; cnt < count; ++cnt) {
@@ -169,7 +169,7 @@ bool QSystemSemaphorePrivate::modifySemaphore(int count)
             }
             setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore (sem_wait)"));
 #if defined QSYSTEMSEMAPHORE_DEBUG
-            qDebug() << QLatin1String("QSystemSemaphore::modify sem_wait failed") << count << errno;
+            qDebug("QSystemSemaphore::modify sem_wait failed %d %d", count, errno);
 #endif
             return false;
         }
diff --git a/src/corelib/kernel/qsystemsemaphore_systemv.cpp b/src/corelib/kernel/qsystemsemaphore_systemv.cpp
index f4fdfa5f58..1967899a58 100644
--- a/src/corelib/kernel/qsystemsemaphore_systemv.cpp
+++ b/src/corelib/kernel/qsystemsemaphore_systemv.cpp
@@ -187,7 +187,8 @@ bool QSystemSemaphorePrivate::modifySemaphore(int count)
         }
         setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore"));
 #if defined QSYSTEMSEMAPHORE_DEBUG
-        qDebug() << QLatin1String("QSystemSemaphore::modify failed") << count << semctl(semaphore, 0, GETVAL) << errno << EIDRM << EINVAL;
+        qDebug("QSystemSemaphore::modify failed %d %d %d %d %d",
+               count, int(semctl(semaphore, 0, GETVAL)), int(errno), int(EIDRM), int(EINVAL);
 #endif
         return false;
     }
diff --git a/src/gui/image/qimagereader.cpp b/src/gui/image/qimagereader.cpp
index 8bf0ce3523..dd1f0c8943 100644
--- a/src/gui/image/qimagereader.cpp
+++ b/src/gui/image/qimagereader.cpp
@@ -450,8 +450,8 @@ static QImageIOHandler *createReadHandlerHelper(QIODevice *device,
 
             if (handler) {
 #ifdef QIMAGEREADER_DEBUG
-                qDebug() << "QImageReader::createReadHandler: the" << _qt_BuiltInFormats[currentFormat].extension
-                         << "built-in handler can read this data";
+                qDebug("QImageReader::createReadHandler: the %s built-in handler can read this data",
+                       _qt_BuiltInFormats[currentFormat].extension);
 #endif
                 break;
             }
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 129e93db8d..1f102dcec5 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -1186,7 +1186,7 @@ static void init_plugins(const QList<QByteArray> &pluginList)
         if (plugin)
             QGuiApplicationPrivate::generic_plugin_list.append(plugin);
         else
-            qWarning() << "No such plugin for spec " << pluginSpec;
+            qWarning("No such plugin for spec \"%s\"", pluginSpec.constData());
     }
 }
 
diff --git a/src/gui/kernel/qhighdpiscaling.cpp b/src/gui/kernel/qhighdpiscaling.cpp
index 4cc9e95e81..d6e467db59 100644
--- a/src/gui/kernel/qhighdpiscaling.cpp
+++ b/src/gui/kernel/qhighdpiscaling.cpp
@@ -68,10 +68,11 @@ static inline qreal initialGlobalScaleFactor()
         }
     } else {
         if (qEnvironmentVariableIsSet(legacyDevicePixelEnvVar)) {
-            qWarning() << "Warning:" << legacyDevicePixelEnvVar << "is deprecated. Instead use:" << endl
-                       << "   " << autoScreenEnvVar << "to enable platform plugin controlled per-screen factors." << endl
-                       << "   " << screenFactorsEnvVar << "to set per-screen factors." << endl
-                       << "   " << scaleFactorEnvVar << "to set the application global scale factor.";
+            qWarning("Warning: %s is deprecated. Instead use:\n"
+                     "   %s to enable platform plugin controlled per-screen factors.\n"
+                     "   %s to set per-screen factors.\n"
+                     "   %s to set the application global scale factor.",
+                     legacyDevicePixelEnvVar, autoScreenEnvVar, screenFactorsEnvVar, scaleFactorEnvVar);
 
             int dpr = qEnvironmentVariableIntValue(legacyDevicePixelEnvVar);
             if (dpr > 0)
diff --git a/src/gui/opengl/qopenglengineshadermanager.cpp b/src/gui/opengl/qopenglengineshadermanager.cpp
index 4e3d14ba37..1d3e47f93b 100644
--- a/src/gui/opengl/qopenglengineshadermanager.cpp
+++ b/src/gui/opengl/qopenglengineshadermanager.cpp
@@ -390,7 +390,7 @@ QOpenGLEngineShaderProg *QOpenGLEngineSharedShaders::findProgramInCache(const QO
             fragShader->setObjectName(QString::fromLatin1(description));
 #endif
             if (!fragShader->compileSourceCode(fragSource)) {
-                qWarning() << "Warning:" << description << "failed to compile!";
+                qWarning("Warning: \"%s\" failed to compile!", description.constData());
                 break;
             }
 
@@ -405,7 +405,7 @@ QOpenGLEngineShaderProg *QOpenGLEngineSharedShaders::findProgramInCache(const QO
             vertexShader->setObjectName(QString::fromLatin1(description));
 #endif
             if (!vertexShader->compileSourceCode(vertexSource)) {
-                qWarning() << "Warning:" << description << "failed to compile!";
+                qWarning("Warning: \"%s\" failed to compile!", description.constData());
                 break;
             }
 
diff --git a/src/gui/opengl/qopenglshaderprogram.cpp b/src/gui/opengl/qopenglshaderprogram.cpp
index 4134513210..f076e10e20 100644
--- a/src/gui/opengl/qopenglshaderprogram.cpp
+++ b/src/gui/opengl/qopenglshaderprogram.cpp
@@ -337,9 +337,10 @@ bool QOpenGLShaderPrivate::compile(QOpenGLShader *q)
 
         // Dump the source code if we got it
         if (sourceCodeBuffer) {
-            qWarning("*** Problematic %s shader source code ***", type);
-            qWarning() << qPrintable(QString::fromLatin1(sourceCodeBuffer));
-            qWarning("***");
+            qWarning("*** Problematic %s shader source code ***\n"
+                     "%ls\n"
+                     "***",
+                     type, qUtf16Printable(QString::fromLatin1(sourceCodeBuffer)));
         }
 
         // Cleanup
@@ -1215,8 +1216,7 @@ int QOpenGLShaderProgram::attributeLocation(const char *name) const
     if (d->linked && d->programGuard && d->programGuard->id()) {
         return d->glfuncs->glGetAttribLocation(d->programGuard->id(), name);
     } else {
-        qWarning() << "QOpenGLShaderProgram::attributeLocation(" << name
-                   << "): shader program is not linked";
+        qWarning("QOpenGLShaderProgram::attributeLocation(%s): shader program is not linked", name);
         return -1;
     }
 }
@@ -1479,7 +1479,7 @@ void QOpenGLShaderProgram::setAttributeValue
     Q_D(QOpenGLShaderProgram);
     Q_UNUSED(d);
     if (rows < 1 || rows > 4) {
-        qWarning() << "QOpenGLShaderProgram::setAttributeValue: rows" << rows << "not supported";
+        qWarning("QOpenGLShaderProgram::setAttributeValue: rows %d not supported", rows);
         return;
     }
     if (location != -1) {
@@ -1891,8 +1891,7 @@ int QOpenGLShaderProgram::uniformLocation(const char *name) const
     if (d->linked && d->programGuard && d->programGuard->id()) {
         return d->glfuncs->glGetUniformLocation(d->programGuard->id(), name);
     } else {
-        qWarning() << "QOpenGLShaderProgram::uniformLocation(" << name
-                   << "): shader program is not linked";
+        qWarning("QOpenGLShaderProgram::uniformLocation(%s): shader program is not linked", name);
         return -1;
     }
 }
@@ -2819,7 +2818,7 @@ void QOpenGLShaderProgram::setUniformValueArray(int location, const GLfloat *val
         else if (tupleSize == 4)
             d->glfuncs->glUniform4fv(location, count, values);
         else
-            qWarning() << "QOpenGLShaderProgram::setUniformValue: size" << tupleSize << "not supported";
+            qWarning("QOpenGLShaderProgram::setUniformValue: size %d not supported", tupleSize);
     }
 }
 
diff --git a/src/network/access/qspdyprotocolhandler.cpp b/src/network/access/qspdyprotocolhandler.cpp
index 1a6dd04ecb..4641516549 100644
--- a/src/network/access/qspdyprotocolhandler.cpp
+++ b/src/network/access/qspdyprotocolhandler.cpp
@@ -458,7 +458,7 @@ bool QSpdyProtocolHandler::uncompressHeader(const QByteArray &input, QByteArray
             break;
         }
         default: {
-            qWarning() << "got unexpected zlib return value:" << zlibRet;
+            qWarning("got unexpected zlib return value: %d", zlibRet);
             return false;
         }
         }
@@ -849,7 +849,7 @@ void QSpdyProtocolHandler::handleControlFrame(const QByteArray &frameHeaders) //
         break;
     }
     default:
-        qWarning() << "cannot handle frame of type" << type;
+        qWarning("cannot handle frame of type %d", int(type));
     }
 }
 
@@ -1085,7 +1085,7 @@ void QSpdyProtocolHandler::handleSETTINGS(char flags, quint32 /*length*/, const
             break;
         }
         default:
-            qWarning() << "found unknown settings value" << value;
+            qWarning("found unknown settings value %u", uint(value));
         }
     }
 }
@@ -1124,7 +1124,7 @@ void QSpdyProtocolHandler::handleGOAWAY(char /*flags*/, quint32 /*length*/,
         break;
     }
     default:
-        qWarning() << "unexpected status code" << statusCode;
+        qWarning("unexpected status code %d", int(statusCode));
         errorCode = QNetworkReply::ProtocolUnknownError;
     }
 
diff --git a/src/plugins/platforms/qnx/qqnxbuttoneventnotifier.cpp b/src/plugins/platforms/qnx/qqnxbuttoneventnotifier.cpp
index a08ac2b839..90a09d3087 100644
--- a/src/plugins/platforms/qnx/qqnxbuttoneventnotifier.cpp
+++ b/src/plugins/platforms/qnx/qqnxbuttoneventnotifier.cpp
@@ -97,7 +97,7 @@ void QQnxButtonEventNotifier::start()
     m_readNotifier = new QSocketNotifier(m_fd, QSocketNotifier::Read);
     QObject::connect(m_readNotifier, SIGNAL(activated(int)), this, SLOT(updateButtonStates()));
 
-    qButtonDebug() << "successfully connected to Navigator. fd =" << m_fd;
+    qButtonDebug("successfully connected to Navigator. fd = %d", m_fd);
 }
 
 void QQnxButtonEventNotifier::updateButtonStates()
@@ -121,7 +121,7 @@ void QQnxButtonEventNotifier::updateButtonStates()
     // Ensure data is null terminated
     buffer[bytes] = '\0';
 
-    qButtonDebug() << "received PPS message:\n" << buffer;
+    qButtonDebug("received PPS message:\n%s", buffer);
 
     // Process received message
     QByteArray ppsData = QByteArray::fromRawData(buffer, bytes);
diff --git a/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp b/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp
index 79ff74b113..ce3a445d7c 100644
--- a/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp
+++ b/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp
@@ -721,7 +721,7 @@ void QQnxInputContext::update(Qt::InputMethodQueries queries)
             initEvent(&caretEvent.event, sInputSession, EVENT_CARET, CARET_POS_CHANGED, sizeof(caretEvent));
             caretEvent.old_pos = lastCaret;
             caretEvent.new_pos = m_caretPosition;
-            qInputContextDebug() << "ictrl_dispatch_event caret changed" << lastCaret << m_caretPosition;
+            qInputContextDebug("ictrl_dispatch_event caret changed %d %d", lastCaret, m_caretPosition);
             p_ictrl_dispatch_event(&caretEvent.event);
         }
     }
@@ -914,7 +914,7 @@ bool QQnxInputContext::handleKeyboardEvent(int flags, int sym, int mod, int scan
             navigation_event_t navEvent;
             initEvent(&navEvent.event, sInputSession, EVENT_NAVIGATION, key, sizeof(navEvent));
             navEvent.magnitude = 1;
-            qInputContextDebug() << "ictrl_dispatch_even navigation" << key;
+            qInputContextDebug("ictrl_dispatch_even navigation %d", key);
             p_ictrl_dispatch_event(&navEvent.event);
         }
     } else {
@@ -927,7 +927,7 @@ bool QQnxInputContext::handleKeyboardEvent(int flags, int sym, int mod, int scan
         keyEvent.sequence_id = sequenceId;
 
         p_ictrl_dispatch_event(&keyEvent.event);
-        qInputContextDebug() << "ictrl_dispatch_even key" << key;
+        qInputContextDebug("ictrl_dispatch_even key %d", key);
     }
 
     return true;
@@ -943,7 +943,7 @@ void QQnxInputContext::updateCursorPosition()
     QCoreApplication::sendEvent(input, &query);
     m_caretPosition = query.value(Qt::ImCursorPosition).toInt();
 
-    qInputContextDebug() << m_caretPosition;
+    qInputContextDebug("%d", m_caretPosition);
 }
 
 void QQnxInputContext::endComposition()
@@ -1116,7 +1116,7 @@ int32_t QQnxInputContext::processEvent(event_t *event)
         int flags = KEY_SYM_VALID | KEY_CAP_VALID;
         if (event->event_id == IMF_KEY_DOWN)
             flags |= KEY_DOWN;
-        qInputContextDebug() << "EVENT_KEY" << flags << keySym;
+        qInputContextDebug("EVENT_KEY %d %d", flags, keySym);
         QQnxScreenEventHandler::injectKeyboardEvent(flags, keySym, modifiers, 0, keyCap);
         result = 0;
         break;
@@ -1156,7 +1156,7 @@ int32_t QQnxInputContext::onCommitText(spannable_string_t *text, int32_t new_cur
 
 int32_t QQnxInputContext::onDeleteSurroundingText(int32_t left_length, int32_t right_length)
 {
-    qInputContextDebug() << "L:" << left_length << " R:" << right_length;
+    qInputContextDebug("L: %d R: %d", int(left_length), int(right_length));
 
     QObject *input = qGuiApp->focusObject();
     if (!input)
diff --git a/src/plugins/platforms/qnx/qqnxintegration.cpp b/src/plugins/platforms/qnx/qqnxintegration.cpp
index 3a0e97af6e..9d38742d6f 100644
--- a/src/plugins/platforms/qnx/qqnxintegration.cpp
+++ b/src/plugins/platforms/qnx/qqnxintegration.cpp
@@ -453,11 +453,11 @@ void QQnxIntegration::createDisplays()
         Q_SCREEN_CHECKERROR(result, "Failed to query display attachment");
 
         if (!isAttached) {
-            qIntegrationDebug() << "Skipping non-attached display" << i;
+            qIntegrationDebug("Skipping non-attached display %d", i);
             continue;
         }
 
-        qIntegrationDebug() << "Creating screen for display" << i;
+        qIntegrationDebug("Creating screen for display %d", i);
         createDisplay(displays[i], /*isPrimary=*/false);
     } // of displays iteration
 }
diff --git a/src/plugins/platforms/qnx/qqnxnavigatoreventhandler.cpp b/src/plugins/platforms/qnx/qqnxnavigatoreventhandler.cpp
index 4955938a3a..0e16764b79 100644
--- a/src/plugins/platforms/qnx/qqnxnavigatoreventhandler.cpp
+++ b/src/plugins/platforms/qnx/qqnxnavigatoreventhandler.cpp
@@ -63,14 +63,14 @@ bool QQnxNavigatorEventHandler::handleOrientationCheck(int angle)
 {
     // reply to navigator that (any) orientation is acceptable
     // TODO: check if top window flags prohibit orientation change
-    qNavigatorEventHandlerDebug() << "angle=" << angle;
+    qNavigatorEventHandlerDebug("angle=%d", angle);
     return true;
 }
 
 void QQnxNavigatorEventHandler::handleOrientationChange(int angle)
 {
     // update screen geometry and reply to navigator that we're ready
-    qNavigatorEventHandlerDebug() << "angle=" << angle;
+    qNavigatorEventHandlerDebug("angle=%d", angle);
     emit rotationChanged(angle);
 }
 
diff --git a/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp b/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp
index 9ccda2d94a..1f630863b7 100644
--- a/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp
+++ b/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp
@@ -91,8 +91,7 @@ void QQnxNavigatorEventNotifier::start()
     errno = 0;
     m_fd = open(navigatorControlPath, O_RDWR);
     if (m_fd == -1) {
-        qNavigatorEventNotifierDebug() << "failed to open navigator pps:"
-                                                      << strerror(errno);
+        qNavigatorEventNotifierDebug("failed to open navigator pps: %s", strerror(errno));
         return;
     }
 
diff --git a/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp b/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp
index fd1bbc4a85..d5234ca92f 100644
--- a/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp
+++ b/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp
@@ -79,7 +79,7 @@ bool QQnxNavigatorPps::openPpsConnection()
         return false;
     }
 
-    qNavigatorDebug() << "successfully connected to Navigator. fd=" << m_fd;
+    qNavigatorDebug("successfully connected to Navigator. fd=%d", m_fd);
 
     return true;
 }
diff --git a/src/plugins/platforms/qnx/qqnxscreen.cpp b/src/plugins/platforms/qnx/qqnxscreen.cpp
index 16ddcd784b..678e83cd57 100644
--- a/src/plugins/platforms/qnx/qqnxscreen.cpp
+++ b/src/plugins/platforms/qnx/qqnxscreen.cpp
@@ -340,11 +340,12 @@ qreal QQnxScreen::refreshRate() const
         qWarning("QQnxScreen: Failed to query screen mode. Using default value of 60Hz");
         return 60.0;
     }
-    qScreenDebug() << "screen mode:" << endl
-                   << "      width =" << displayMode.width << endl
-                   << "     height =" << displayMode.height << endl
-                   << "    refresh =" << displayMode.refresh << endl
-                   << " interlaced =" << displayMode.interlaced;
+    qScreenDebug("screen mode:\n"
+                 "      width = %u\n"
+                 "     height = %u\n"
+                 "    refresh = %u\n"
+                 " interlaced = %u",
+                 uint(displayMode.width), uint(displayMode.height), uint(displayMode.refresh), uint(displayMode.interlaced));
     return static_cast<qreal>(displayMode.refresh);
 }
 
@@ -404,7 +405,7 @@ static bool isOrthogonal(int angle1, int angle2)
 
 void QQnxScreen::setRotation(int rotation)
 {
-    qScreenDebug() << "orientation =" << rotation;
+    qScreenDebug("orientation = %d", rotation);
     // Check if rotation changed
     // We only want to rotate if we are the primary screen
     if (m_currentRotation != rotation && isPrimaryScreen()) {
diff --git a/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp b/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp
index 599d43a8c8..42651732c2 100644
--- a/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp
+++ b/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp
@@ -147,7 +147,7 @@ bool QQnxScreenEventHandler::handleEvent(screen_event_t event, int qnxType)
 
     default:
         // event ignored
-        qScreenEventDebug() << "unknown event" << qnxType;
+        qScreenEventDebug("unknown event %d", qnxType);
         return false;
     }
 
diff --git a/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp b/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp
index 1174dc6ab3..025c03c058 100644
--- a/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp
+++ b/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp
@@ -164,7 +164,7 @@ void QQnxVirtualKeyboardPps::ppsDataReady()
 {
     ssize_t nread = qt_safe_read(m_fd, m_buffer, ms_bufferSize - 1);
 
-    qVirtualKeyboardDebug() << "keyboardMessage size: " << nread;
+    qVirtualKeyboardDebug("keyboardMessage size: %zd", nread);
     if (nread < 0){
         connect(); // reconnect
         return;
@@ -230,7 +230,7 @@ void QQnxVirtualKeyboardPps::handleKeyboardInfoMessage()
     }
     setHeight(newHeight);
 
-    qVirtualKeyboardDebug() << "size=" << newHeight;
+    qVirtualKeyboardDebug("size=%d", newHeight);
 }
 
 bool QQnxVirtualKeyboardPps::showKeyboard()
diff --git a/src/widgets/accessible/itemviews.cpp b/src/widgets/accessible/itemviews.cpp
index ebe8efc79e..ecb84d8b50 100644
--- a/src/widgets/accessible/itemviews.cpp
+++ b/src/widgets/accessible/itemviews.cpp
@@ -512,7 +512,7 @@ QAccessibleInterface *QAccessibleTable::child(int logicalIndex) const
     if (!iface) {
         QModelIndex index = view()->model()->index(row, column, view()->rootIndex());
         if (Q_UNLIKELY(!index.isValid())) {
-            qWarning() << "QAccessibleTable::child: Invalid index at: " << row << column;
+            qWarning("QAccessibleTable::child: Invalid index at: %d %d", row, column);
             return 0;
         }
         iface = new QAccessibleTableCell(view(), index, cellRole());
@@ -783,7 +783,7 @@ QAccessibleInterface *QAccessibleTree::cellAt(int row, int column) const
 {
     QModelIndex index = indexFromLogical(row, column);
     if (Q_UNLIKELY(!index.isValid())) {
-        qWarning() << "Requested invalid tree cell: " << row << column;
+        qWarning("Requested invalid tree cell: %d %d", row, column);
         return 0;
     }
     const QTreeView *treeView = qobject_cast<const QTreeView*>(view());
diff --git a/src/widgets/kernel/qgesturemanager.cpp b/src/widgets/kernel/qgesturemanager.cpp
index 8af3516d4b..777be8525e 100644
--- a/src/widgets/kernel/qgesturemanager.cpp
+++ b/src/widgets/kernel/qgesturemanager.cpp
@@ -75,7 +75,7 @@ static inline int panTouchPoints()
         const int result = qEnvironmentVariableIntValue(panTouchPointVariable, &ok);
         if (ok && result >= 1)
             return result;
-        qWarning() << "Ignoring invalid value of " << panTouchPointVariable;
+        qWarning("Ignoring invalid value of %s", panTouchPointVariable);
     }
     // Pan should use 1 finger on a touch screen and 2 fingers on touch pads etc.
     // where 1 finger movements are used for mouse event synthetization. For now,
diff --git a/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm b/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm
index 477bb92601..2d19780461 100644
--- a/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm
+++ b/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm
@@ -100,8 +100,9 @@ inline QPlatformNativeInterface::NativeResourceForIntegrationFunction resolvePla
     QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
         nativeInterface->nativeResourceFunctionForIntegration(functionName);
     if (Q_UNLIKELY(!function))
-         qWarning() << "Qt could not resolve function" << functionName
-                    << "from QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()";
+         qWarning("Qt could not resolve function %s from "
+                  "QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()",
+                  functionName.constData());
     return function;
 }
 } //namespsace
diff --git a/src/widgets/widgets/qmacnativewidget_mac.mm b/src/widgets/widgets/qmacnativewidget_mac.mm
index 6c113b556f..b6c5179989 100644
--- a/src/widgets/widgets/qmacnativewidget_mac.mm
+++ b/src/widgets/widgets/qmacnativewidget_mac.mm
@@ -89,8 +89,9 @@ inline QPlatformNativeInterface::NativeResourceForIntegrationFunction resolvePla
     QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
         nativeInterface->nativeResourceFunctionForIntegration(functionName);
     if (Q_UNLIKELY(!function))
-         qWarning() << "Qt could not resolve function" << functionName
-                    << "from QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()";
+         qWarning("Qt could not resolve function %s from "
+                  "QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()",
+                  functionName.constData());
     return function;
 }
 } //namespsace
diff --git a/src/widgets/widgets/qmenu_mac.mm b/src/widgets/widgets/qmenu_mac.mm
index 29f5913b5d..d48041b385 100644
--- a/src/widgets/widgets/qmenu_mac.mm
+++ b/src/widgets/widgets/qmenu_mac.mm
@@ -62,8 +62,9 @@ inline QPlatformNativeInterface::NativeResourceForIntegrationFunction resolvePla
     QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
         nativeInterface->nativeResourceFunctionForIntegration(functionName);
     if (Q_UNLIKELY(!function))
-         qWarning() << "Qt could not resolve function" << functionName
-                    << "from QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()";
+         qWarning("Qt could not resolve function %s from "
+                  "QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()",
+                  functionName.constData());
     return function;
 }
 } //namespsace