Qt: Handle qsizetype.

Qt 5.10 added qsizetype, aka an ssize_t and Qt 6 makes extensive use of
it. Add a compatibility typedef and use it where we can. Cast it away
where we can't.

30 files changed, 68 insertions, 71 deletions

diff --git a/ui/qt/about_dialog.cpp b/ui/qt/about_dialog.cpp
index 002e4d4ba0..007f3cb18d 100644
--- a/ui/qt/about_dialog.cpp
+++ b/ui/qt/about_dialog.cpp
@@ -534,7 +534,7 @@ void AboutDialog::handleCopyMenu(QPoint pos)
     connect(copyColumnAction, SIGNAL(triggered()), this, SLOT(copyActionTriggered()));
 
     QModelIndexList selectedRows = tree->selectionModel()->selectedRows();
-    QAction * copyRowAction = menu->addAction(tr("Copy Row(s)", "", selectedRows.count()));
+    QAction * copyRowAction = menu->addAction(tr("Copy Row(s)", "", static_cast<int>(selectedRows.count())));
     copyRowAction->setData(VariantPointer<QTreeView>::asQVariant(tree));
     connect(copyRowAction, SIGNAL(triggered()), this, SLOT(copyRowActionTriggered()));
 
diff --git a/ui/qt/bluetooth_device_dialog.cpp b/ui/qt/bluetooth_device_dialog.cpp
index cddedfd748..147b97ea73 100644
--- a/ui/qt/bluetooth_device_dialog.cpp
+++ b/ui/qt/bluetooth_device_dialog.cpp
@@ -379,7 +379,6 @@ tap_packet_status BluetoothDeviceDialog::tapPacket(void *tapinfo_ptr, packet_inf
     bluetooth_device_tap_t       *tap_device = static_cast<bluetooth_device_tap_t *>(const_cast<void *>(data));
     QString                       bd_addr;
     QString                       bd_addr_oui;
-    QString                       name;
     const gchar                  *manuf;
     QTableWidget                 *tableWidget;
     QTableWidgetItem             *item;
@@ -404,7 +403,7 @@ tap_packet_status BluetoothDeviceDialog::tapPacket(void *tapinfo_ptr, packet_inf
             int pos;
 
             bd_addr_oui = QString(manuf);
-            pos = bd_addr_oui.indexOf('_');
+            pos = static_cast<int>(bd_addr_oui.indexOf('_'));
             if (pos < 0) {
                 manuf = NULL;
             } else {
diff --git a/ui/qt/bluetooth_devices_dialog.cpp b/ui/qt/bluetooth_devices_dialog.cpp
index ee3f65d20a..b0fe53e5fe 100644
--- a/ui/qt/bluetooth_devices_dialog.cpp
+++ b/ui/qt/bluetooth_devices_dialog.cpp
@@ -295,7 +295,7 @@ tap_packet_status BluetoothDevicesDialog::tapPacket(void *tapinfo_ptr, packet_in
             int pos;
 
             bd_addr_oui = QString(manuf);
-            pos = bd_addr_oui.indexOf('_');
+            pos = static_cast<int>(bd_addr_oui.indexOf('_'));
             if (pos < 0) {
                 manuf = NULL;
             } else {
diff --git a/ui/qt/capture_file_dialog.cpp b/ui/qt/capture_file_dialog.cpp
index c1ccf61d44..304b64be99 100644
--- a/ui/qt/capture_file_dialog.cpp
+++ b/ui/qt/capture_file_dialog.cpp
@@ -516,7 +516,7 @@ void CaptureFileDialog::fixFilenameExtension()
     // Find suffixes such as "pcap" or "pcap.gz" if any
     if (!fi.suffix().isEmpty()) {
         QStringList current_suffixes(fi.suffix());
-        int pos = filename.lastIndexOf('.', -2 - current_suffixes.at(0).size());
+        int pos = static_cast<int>(filename.lastIndexOf('.', -2 - current_suffixes.at(0).size()));
         if (pos > 0) {
             current_suffixes.prepend(filename.right(filename.size() - (pos + 1)));
         }
diff --git a/ui/qt/coloring_rules_dialog.cpp b/ui/qt/coloring_rules_dialog.cpp
index a36193a723..9a7c92d325 100644
--- a/ui/qt/coloring_rules_dialog.cpp
+++ b/ui/qt/coloring_rules_dialog.cpp
@@ -316,7 +316,7 @@ void ColoringRulesDialog::colorRuleSelectionChanged(const QItemSelection&, const
         selectedRows.insert(index.row(), index);
     }
 
-    int num_selected = selectedRows.count();
+    qsizetype num_selected = selectedRows.count();
     if (num_selected == 1) {
         setColorButtons(selectedList[0]);
     }
@@ -400,7 +400,7 @@ void ColoringRulesDialog::on_newToolButton_clicked()
 void ColoringRulesDialog::on_deleteToolButton_clicked()
 {
     QModelIndexList selectedList = ui->coloringRulesTreeView->selectionModel()->selectedIndexes();
-    int num_selected = selectedList.count()/colorRuleModel_.columnCount();
+    qsizetype num_selected = selectedList.count() / colorRuleModel_.columnCount();
     if (num_selected > 0) {
         //list is not guaranteed to be sorted, so force it
         std::sort(selectedList.begin(), selectedList.end());
@@ -408,7 +408,7 @@ void ColoringRulesDialog::on_deleteToolButton_clicked()
         //walk the list from the back because deleting a value in
         //the middle will leave the selectedList out of sync and
         //delete the wrong elements
-        for (int i = selectedList.count()-1; i >= 0; i--) {
+        for (int i = static_cast<int>(selectedList.count()) - 1; i >= 0; i--) {
             QModelIndex deleteIndex = selectedList[i];
             //selectedList includes all cells, use first column as key to remove row
             if (deleteIndex.isValid() && (deleteIndex.column() == 0)) {
@@ -443,7 +443,7 @@ void ColoringRulesDialog::on_buttonBox_clicked(QAbstractButton *button)
             checkUnknownColorfilters();
         }
     } else if (button == export_button_) {
-        int num_items = ui->coloringRulesTreeView->selectionModel()->selectedIndexes().count()/colorRuleModel_.columnCount();
+        int num_items = static_cast<int>(ui->coloringRulesTreeView->selectionModel()->selectedIndexes().count()) / colorRuleModel_.columnCount();
 
         if (num_items < 1) {
             num_items = colorRuleModel_.rowCount();
diff --git a/ui/qt/extcap_options_dialog.cpp b/ui/qt/extcap_options_dialog.cpp
index 1a963d6ed4..aa00e40e9d 100644
--- a/ui/qt/extcap_options_dialog.cpp
+++ b/ui/qt/extcap_options_dialog.cpp
@@ -271,7 +271,7 @@ void ExtcapOptionsDialog::updateWidgets()
         ui->buttonBox->button(QDialogButtonBox::Ok)->setEnabled(true);
         return;
     }
-    ui->checkSaveOnStart->setText(tr("Save parameter(s) on capture start", "", extcapArguments.count()));
+    ui->checkSaveOnStart->setText(tr("Save parameter(s) on capture start", "", static_cast<int>(extcapArguments.count())));
 
     QStringList groupKeys;
     QString defaultKeyName(tr("Default"));
@@ -479,9 +479,6 @@ void ExtcapOptionsDialog::on_buttonBox_clicked(QAbstractButton *button)
 
 void ExtcapOptionsDialog::resetValues()
 {
-    ExtcapArgumentList::const_iterator iter;
-    QString value;
-
     int count = ui->verticalLayout->count();
     if (count > 0)
     {
diff --git a/ui/qt/filter_dialog.cpp b/ui/qt/filter_dialog.cpp
index 09f49b360f..eff1eae1b7 100644
--- a/ui/qt/filter_dialog.cpp
+++ b/ui/qt/filter_dialog.cpp
@@ -116,7 +116,7 @@ void FilterDialog::updateWidgets()
     if (! ui->filterTreeView->selectionModel())
         return;
 
-    int num_selected = ui->filterTreeView->selectionModel()->selectedRows().count();
+    qsizetype num_selected = ui->filterTreeView->selectionModel()->selectedRows().count();
 
     ui->copyToolButton->setEnabled(num_selected == 1);
     ui->deleteToolButton->setEnabled(num_selected > 0);
diff --git a/ui/qt/follow_stream_dialog.cpp b/ui/qt/follow_stream_dialog.cpp
index 907138430d..1f3bcc759f 100644
--- a/ui/qt/follow_stream_dialog.cpp
+++ b/ui/qt/follow_stream_dialog.cpp
@@ -327,7 +327,7 @@ void FollowStreamDialog::saveAs()
     }
 
     QDataStream out(&file);
-    out.writeRawData(bytes.constData(), bytes.size());
+    out.writeRawData(bytes.constData(), static_cast<int>(bytes.size()));
 }
 
 void FollowStreamDialog::helpButton()
diff --git a/ui/qt/funnel_text_dialog.cpp b/ui/qt/funnel_text_dialog.cpp
index 5a8c3f38e4..527d5a5513 100644
--- a/ui/qt/funnel_text_dialog.cpp
+++ b/ui/qt/funnel_text_dialog.cpp
@@ -160,8 +160,8 @@ void FunnelTextDialog::on_findLineEdit_textChanged(const QString &pattern)
         QRegularExpressionMatchIterator iter = re.globalMatch(ui->textEdit->toPlainText());
         while (iter.hasNext()) {
             QRegularExpressionMatch match = iter.next();
-            csr.setPosition(match.capturedStart(), QTextCursor::MoveAnchor);
-            csr.setPosition(match.capturedEnd(), QTextCursor::KeepAnchor);
+            csr.setPosition(static_cast<int>(match.capturedStart()), QTextCursor::MoveAnchor);
+            csr.setPosition(static_cast<int>(match.capturedEnd()), QTextCursor::KeepAnchor);
             csr.setCharFormat(highlight_fmt);
         }
     }
diff --git a/ui/qt/iax2_analysis_dialog.cpp b/ui/qt/iax2_analysis_dialog.cpp
index 59c4b311fe..5622a71a26 100644
--- a/ui/qt/iax2_analysis_dialog.cpp
+++ b/ui/qt/iax2_analysis_dialog.cpp
@@ -1107,7 +1107,7 @@ void Iax2AnalysisDialog::saveAudio(Iax2AnalysisDialog::StreamDirection direction
         }
         }
 
-        int chunk_size = 65536;
+        qsizetype chunk_size = 65536;
         /* XXX how do you just copy the file? */
         while (chunk_size > 0) {
             if (stop_flag)
diff --git a/ui/qt/import_text_dialog.cpp b/ui/qt/import_text_dialog.cpp
index dff793e2c9..428ce66aa3 100644
--- a/ui/qt/import_text_dialog.cpp
+++ b/ui/qt/import_text_dialog.cpp
@@ -642,7 +642,7 @@ bool ImportTextDialog::checkDateTimeFormat(const QString &time_format)
      * probably better */
     if (time_format == "ISO") {
         ret = true;
-    } else while ((idx = time_format.indexOf("%", idx)) != -1) {
+    } else while ((idx = static_cast<int>(time_format.indexOf("%", idx))) != -1) {
         idx++;
         if ((idx == time_format.size()) || !valid_code.contains(time_format[idx])) {
             return false;
diff --git a/ui/qt/interface_frame.cpp b/ui/qt/interface_frame.cpp
index 64cab4dacb..c0bb5055cc 100644
--- a/ui/qt/interface_frame.cpp
+++ b/ui/qt/interface_frame.cpp
@@ -97,7 +97,7 @@ InterfaceFrame::InterfaceFrame(QWidget * parent)
     proxy_model_.setSourceModel(&source_model_);
 
     info_model_.setSourceModel(&proxy_model_);
-    info_model_.setColumn(columns.indexOf(IFTREE_COL_STATS));
+    info_model_.setColumn(static_cast<int>(columns.indexOf(IFTREE_COL_STATS)));
 
     ui->interfaceTree->setModel(&info_model_);
 
diff --git a/ui/qt/main_window.cpp b/ui/qt/main_window.cpp
index 88c7799eca..82c197c2a2 100644
--- a/ui/qt/main_window.cpp
+++ b/ui/qt/main_window.cpp
@@ -1077,7 +1077,7 @@ void MainWindow::dropEvent(QDropEvent *event)
     }
 
     /* merge the files in chronological order */
-    if (cf_merge_files_to_tempfile(this, global_capture_opts.temp_dir, &tmpname, local_files.size(),
+    if (cf_merge_files_to_tempfile(this, global_capture_opts.temp_dir, &tmpname, static_cast<int>(local_files.size()),
                                    in_filenames,
                                    wtap_pcapng_file_type_subtype(),
                                    FALSE) == CF_OK) {
@@ -2136,7 +2136,7 @@ void MainWindow::initMainToolbarIcons()
     main_ui_->actionViewColorizePacketList->setIcon(StockIcon("x-colorize-packets"));
 
     QList<QKeySequence> zi_seq = main_ui_->actionViewZoomIn->shortcuts();
-    zi_seq << QKeySequence(Qt::CTRL + Qt::Key_Equal);
+    zi_seq << QKeySequence(Qt::CTRL | Qt::Key_Equal);
     main_ui_->actionViewZoomIn->setIcon(StockIcon("zoom-in"));
     main_ui_->actionViewZoomIn->setShortcuts(zi_seq);
     main_ui_->actionViewZoomOut->setIcon(StockIcon("zoom-out"));
diff --git a/ui/qt/main_window_slots.cpp b/ui/qt/main_window_slots.cpp
index 42ad07f8de..8c211ab9ea 100644
--- a/ui/qt/main_window_slots.cpp
+++ b/ui/qt/main_window_slots.cpp
@@ -1214,7 +1214,7 @@ void MainWindow::setEditCommentsMenu()
     }
     if (selectedRows().count() > 1) {
         main_ui_->menuPacketComment->addSeparator();
-        main_ui_->menuPacketComment->addAction(tr("Delete comments from %n packet(s)", nullptr, selectedRows().count()), this, SLOT(actionDeleteCommentsFromPackets()));
+        main_ui_->menuPacketComment->addAction(tr("Delete comments from %n packet(s)", nullptr, static_cast<int>(selectedRows().count())), this, SLOT(actionDeleteCommentsFromPackets()));
     }
 }
 
@@ -1306,8 +1306,8 @@ void MainWindow::setMenusForSelectedPacket()
         }
     }
 
-    main_ui_->actionEditMarkPacket->setText(tr("&Mark/Unmark Packet(s)", "", selectedRows().count()));
-    main_ui_->actionEditIgnorePacket->setText(tr("&Ignore/Unignore Packet(s)", "", selectedRows().count()));
+    main_ui_->actionEditMarkPacket->setText(tr("&Mark/Unmark Packet(s)", "", static_cast<int>(selectedRows().count())));
+    main_ui_->actionEditIgnorePacket->setText(tr("&Ignore/Unignore Packet(s)", "", static_cast<int>(selectedRows().count())));
 
     main_ui_->actionCopyListAsText->setEnabled(selectedRows().count() > 0);
     main_ui_->actionCopyListAsCSV->setEnabled(selectedRows().count() > 0);
diff --git a/ui/qt/models/export_objects_model.cpp b/ui/qt/models/export_objects_model.cpp
index ed42725b59..c5d4c2a3c6 100644
--- a/ui/qt/models/export_objects_model.cpp
+++ b/ui/qt/models/export_objects_model.cpp
@@ -115,7 +115,7 @@ int ExportObjectModel::rowCount(const QModelIndex &parent) const
         return 0;
     }
 
-    return objects_.count();
+    return static_cast<int>(objects_.count());
 }
 
 int ExportObjectModel::columnCount(const QModelIndex&) const
@@ -128,7 +128,7 @@ void ExportObjectModel::addObjectEntry(export_object_entry_t *entry)
     if (entry == NULL)
         return;
 
-    int count = objects_.count();
+    int count = static_cast<int>(objects_.count());
     beginInsertRows(QModelIndex(), count, count);
     objects_.append(VariantPointer<export_object_entry_t>::asQVariant(entry));
     endInsertRows();
diff --git a/ui/qt/models/fileset_entry_model.h b/ui/qt/models/fileset_entry_model.h
index 55655e5368..aa812b0cf7 100644
--- a/ui/qt/models/fileset_entry_model.h
+++ b/ui/qt/models/fileset_entry_model.h
@@ -37,7 +37,7 @@ public:
 
     virtual void appendEntry(const fileset_entry *entry);
     const fileset_entry *getRowEntry(int row) const { return entries_.value(row, NULL); }
-    int entryCount() const { return entries_.count(); }
+    int entryCount() const { return static_cast<int>(entries_.count()); }
     // Calls fileset_delete and clears our model data.
     void clear();
 
diff --git a/ui/qt/models/packet_list_model.cpp b/ui/qt/models/packet_list_model.cpp
index 7d16070248..bac314c809 100644
--- a/ui/qt/models/packet_list_model.cpp
+++ b/ui/qt/models/packet_list_model.cpp
@@ -147,18 +147,18 @@ guint PacketListModel::recreateVisibleRows()
 
         if (fdata->passed_dfilter || fdata->ref_time) {
             visible_rows_ << record;
-            if (number_to_row_.size() <= (int)fdata->num) {
+            if (static_cast<guint32>(number_to_row_.size()) <= fdata->num) {
                 number_to_row_.resize(fdata->num + 10000);
             }
-            number_to_row_[fdata->num] = visible_rows_.count();
+            number_to_row_[fdata->num] = static_cast<int>(visible_rows_.count());
         }
     }
     if (!visible_rows_.isEmpty()) {
-        beginInsertRows(QModelIndex(), 0, visible_rows_.count() - 1);
+        beginInsertRows(QModelIndex(), 0, static_cast<int>(visible_rows_.count()) - 1);
         endInsertRows();
     }
     idle_dissection_row_ = 0;
-    return visible_rows_.count();
+    return static_cast<guint>(visible_rows_.count());
 }
 
 void PacketListModel::clear() {
@@ -376,7 +376,7 @@ void PacketListModel::sort(int column, Qt::SortOrder order)
             if (number_to_row_.size() <= (int)fdata->num) {
                 number_to_row_.resize(fdata->num + 10000);
             }
-            number_to_row_[fdata->num] = visible_rows_.count();
+            number_to_row_[fdata->num] = static_cast<int>(visible_rows_.count());
         }
     }
     emit endResetModel();
@@ -543,7 +543,7 @@ void PacketListModel::emitItemHeightChanged(const QModelIndex &ih_index)
 
 int PacketListModel::rowCount(const QModelIndex &) const
 {
-    return visible_rows_.count();
+    return static_cast<int>(visible_rows_.count());
 }
 
 int PacketListModel::columnCount(const QModelIndex &) const
@@ -658,20 +658,20 @@ QVariant PacketListModel::headerData(int section, Qt::Orientation orientation,
 
 void PacketListModel::flushVisibleRows()
 {
-    gint pos = visible_rows_.count();
+    int pos = static_cast<int>(visible_rows_.count());
 
     if (new_visible_rows_.count() > 0) {
-        emit beginInsertRows(QModelIndex(), pos, pos + new_visible_rows_.count());
+        beginInsertRows(QModelIndex(), pos, pos + static_cast<int>(new_visible_rows_.count()));
         foreach (PacketListRecord *record, new_visible_rows_) {
             frame_data *fdata = record->frameData();
 
             visible_rows_ << record;
-            if (number_to_row_.size() <= (int)fdata->num) {
+            if (static_cast<unsigned int>(number_to_row_.size()) <= fdata->num) {
                 number_to_row_.resize(fdata->num + 10000);
             }
-            number_to_row_[fdata->num] = visible_rows_.count();
+            number_to_row_[fdata->num] = static_cast<int>(visible_rows_.count());
         }
-        emit endInsertRows();
+        endInsertRows();
         new_visible_rows_.resize(0);
     }
 }
@@ -713,7 +713,7 @@ void PacketListModel::dissectIdle(bool reset)
 gint PacketListModel::appendPacket(frame_data *fdata)
 {
     PacketListRecord *record = new PacketListRecord(fdata);
-    gint pos = -1;
+    qsizetype pos = -1;
 
 #ifdef DEBUG_PACKET_LIST_MODEL
     if (fdata->num % 10000 == 1) {
@@ -733,7 +733,7 @@ gint PacketListModel::appendPacket(frame_data *fdata)
         pos = visible_rows_.count() + new_visible_rows_.count() - 1;
     }
 
-    return pos;
+    return static_cast<gint>(pos);
 }
 
 frame_data *PacketListModel::getRowFdata(QModelIndex idx)
diff --git a/ui/qt/profile_dialog.cpp b/ui/qt/profile_dialog.cpp
index 7d4a60cd84..e33e73ddc0 100644
--- a/ui/qt/profile_dialog.cpp
+++ b/ui/qt/profile_dialog.cpp
@@ -615,7 +615,7 @@ void ProfileDialog::exportProfiles(bool exportAllPersonalProfiles)
         QString err;
         if (model_->exportProfiles(zipFile, items, &err))
         {
-            QString msg = tr("%Ln profile(s) exported", "", items.count());
+            QString msg = tr("%Ln profile(s) exported", "", static_cast<int>(items.count()));
             if (skipped > 0)
                 msg.append(tr(", %Ln profile(s) skipped", "", skipped));
             QMessageBox::information(this, tr("Exporting profiles"), msg);
diff --git a/ui/qt/rpc_service_response_time_dialog.cpp b/ui/qt/rpc_service_response_time_dialog.cpp
index 4c27f6b3eb..29e5ab31fc 100644
--- a/ui/qt/rpc_service_response_time_dialog.cpp
+++ b/ui/qt/rpc_service_response_time_dialog.cpp
@@ -366,7 +366,7 @@ void RpcServiceResponseTimeDialog::fillVersionCombo()
     }
     if (versions_.count() > 0) {
         // Select the highest-numbered version.
-        version_combo_->setCurrentIndex(versions_.count() - 1);
+        version_combo_->setCurrentIndex(static_cast<int>(versions_.count()) - 1);
     }
 }
 
diff --git a/ui/qt/rtp_analysis_dialog.cpp b/ui/qt/rtp_analysis_dialog.cpp
index 937b7037d0..71be3ee297 100644
--- a/ui/qt/rtp_analysis_dialog.cpp
+++ b/ui/qt/rtp_analysis_dialog.cpp
@@ -1028,7 +1028,7 @@ void RtpAnalysisDialog::replaceRtpStreams(QVector<rtpstream_id_t *> stream_ids)
     std::lock_guard<std::mutex> lock(mutex_);
     // Delete existing tabs (from last to first)
     if (tabs_.count() > 0) {
-        for(int i=tabs_.count(); i>0; i--) {
+        for(int i = static_cast<int>(tabs_.count()); i>0; i--) {
             closeTab(i-1);
         }
     }
@@ -1095,7 +1095,7 @@ void RtpAnalysisDialog::removeRtpStreams(QVector<rtpstream_id_t *> stream_ids)
         for (int i = 0; i < tabs.size(); i++) {
             tab_info_t *tab = tabs.at(i);
             if (rtpstream_id_equal(&tab->stream.id, id, RTPSTREAM_ID_EQUAL_SSRC))  {
-                closeTab(tabs_.indexOf(tab));
+                closeTab(static_cast<int>(tabs_.indexOf(tab)));
             }
         }
     }
diff --git a/ui/qt/service_response_time_dialog.cpp b/ui/qt/service_response_time_dialog.cpp
index c332c52867..17435699dd 100644
--- a/ui/qt/service_response_time_dialog.cpp
+++ b/ui/qt/service_response_time_dialog.cpp
@@ -183,7 +183,7 @@ ServiceResponseTimeDialog::ServiceResponseTimeDialog(QWidget &parent, CaptureFil
     for (int col = 0; col < NUM_SRT_COLUMNS; col++) {
         header_labels.push_back(service_response_time_get_column_name(col));
     }
-    statsTreeWidget()->setColumnCount(header_labels.count());
+    statsTreeWidget()->setColumnCount(static_cast<int>(header_labels.count()));
     statsTreeWidget()->setHeaderLabels(header_labels);
 
     for (int col = 0; col < statsTreeWidget()->columnCount(); col++) {
diff --git a/ui/qt/show_packet_bytes_dialog.cpp b/ui/qt/show_packet_bytes_dialog.cpp
index c29f65d7c7..d2564f169f 100644
--- a/ui/qt/show_packet_bytes_dialog.cpp
+++ b/ui/qt/show_packet_bytes_dialog.cpp
@@ -620,7 +620,7 @@ void ShowPacketBytesDialog::updatePacketBytes(void)
 
     case ShowAsCArray:
     {
-        int pos = 0, len = field_bytes_.length();
+        int pos = 0, len = static_cast<int>(field_bytes_.length());
         QString text("char packet_bytes[] = {\n");
 
         while (pos < len) {
@@ -657,7 +657,7 @@ void ShowPacketBytesDialog::updatePacketBytes(void)
 
     case ShowAsRustArray:
     {
-        int pos = 0, len = field_bytes_.length();
+        int pos = 0, len = static_cast<int>(field_bytes_.length());
         QString text("let packet_bytes: [u8; _] = [\n");
 
         while (pos < len) {
@@ -709,7 +709,7 @@ void ShowPacketBytesDialog::updatePacketBytes(void)
     case ShowAsEBCDIC:
     {
         QByteArray ba(field_bytes_);
-        EBCDIC_to_ASCII((guint8*)ba.data(), ba.length());
+        EBCDIC_to_ASCII((guint8*)ba.data(), static_cast<int>(ba.length()));
         sanitizeBuffer(ba, false);
         ui->tePacketBytes->setLineWrapMode(QTextEdit::WidgetWidth);
         ui->tePacketBytes->setPlainText(ba);
@@ -718,7 +718,7 @@ void ShowPacketBytesDialog::updatePacketBytes(void)
 
     case ShowAsHexDump:
     {
-        int pos = 0, len = field_bytes_.length();
+        int pos = 0, len = static_cast<int>(field_bytes_.length());
         // Use 16-bit offset if there are <= 65536 bytes, 32-bit offset if there are more
         unsigned int offset_chars = (len - 1 <= 0xFFFF) ? 4 : 8;
         QString text;
@@ -798,7 +798,7 @@ void ShowPacketBytesDialog::updatePacketBytes(void)
     case ShowAsYAML:
     {
         const int base64_raw_len = 57; // Encodes to 76 bytes, common in RFCs
-        int pos = 0, len = field_bytes_.length();
+        int pos = 0, len = static_cast<int>(field_bytes_.length());
         QString text("# Packet Bytes: !!binary |\n");
 
         while (pos < len) {
diff --git a/ui/qt/stats_tree_dialog.cpp b/ui/qt/stats_tree_dialog.cpp
index 3eb64c5bd3..8492e8e57d 100644
--- a/ui/qt/stats_tree_dialog.cpp
+++ b/ui/qt/stats_tree_dialog.cpp
@@ -124,7 +124,7 @@ void StatsTreeDialog::fillTree()
     for (int count = 0; count<st_->num_columns; count++) {
         header_labels.push_back(stats_tree_get_column_name(count));
     }
-    statsTreeWidget()->setColumnCount(header_labels.count());
+    statsTreeWidget()->setColumnCount(static_cast<int>(header_labels.count()));
     statsTreeWidget()->setHeaderLabels(header_labels);
     statsTreeWidget()->setSortingEnabled(false);
 
diff --git a/ui/qt/tap_parameter_dialog.cpp b/ui/qt/tap_parameter_dialog.cpp
index d7e240787b..0275232fda 100644
--- a/ui/qt/tap_parameter_dialog.cpp
+++ b/ui/qt/tap_parameter_dialog.cpp
@@ -259,11 +259,11 @@ QByteArray TapParameterDialog::getTreeAsString(st_format_type format)
             // Iterating over items within this tree.
             for (int col=0; col < ui->statsTreeWidget->columnCount(); col++) {
                 if (col_widths.size() <= col) {
-                    col_widths.append(ui->statsTreeWidget->headerItem()->text(col).length());
+                    col_widths.append(static_cast<int>(ui->statsTreeWidget->headerItem()->text(col).length()));
                 }
                 QVariant var = ui->statsTreeWidget->headerItem()->data(col, Qt::DisplayRole);
                 if (var.userType() == QMetaType::QString) {
-                    col_widths[col] = qMax(col_widths[col], itemDataToPlain(var).length());
+                    col_widths[col] = qMax(col_widths[col], static_cast<int>(itemDataToPlain(var).length()));
                 }
             }
             ++width_it;
@@ -481,7 +481,7 @@ void TapParameterDialog::addFilterActions()
 void TapParameterDialog::addTreeCollapseAllActions()
 {
     ctx_menu_.addSeparator();
-    
+
     QAction *collapse = new QAction(tr("Collapse All"), this);
     ctx_menu_.addAction(collapse);
     connect(collapse, SIGNAL(triggered()), this, SLOT(collapseAllActionTriggered()));
diff --git a/ui/qt/utils/qt_ui_utils.h b/ui/qt/utils/qt_ui_utils.h
index bab40ad08d..044b71d353 100644
--- a/ui/qt/utils/qt_ui_utils.h
+++ b/ui/qt/utils/qt_ui_utils.h
@@ -45,9 +45,10 @@ struct epan_range;
 }
 #endif /* __cplusplus */
 
-// Introduced in Qt 5.4
-#ifndef qUtf8Printable
-#define qUtf8Printable(str) str.toUtf8().constData()
+// qsizetype was added in Qt 5.10.0 and is used in the Qt 6 API.
+#if QT_VERSION < QT_VERSION_CHECK(5, 10, 0)
+#include "include/ws_posix_compat.h"
+typedef ssize_t qsizetype;
 #endif
 
 /*
diff --git a/ui/qt/widgets/byte_view_text.cpp b/ui/qt/widgets/byte_view_text.cpp
index 8f44b4f2da..bb445605e3 100644
--- a/ui/qt/widgets/byte_view_text.cpp
+++ b/ui/qt/widgets/byte_view_text.cpp
@@ -386,7 +386,7 @@ void ByteViewText::drawLine(QPainter *painter, const int offset, const int row_y
 
     // Build our pixel to byte offset vector the first time through.
     bool build_x_pos = x_pos_to_column_.empty() ? true : false;
-    int tvb_len = data_.count();
+    int tvb_len = static_cast<int>(data_.count());
     int max_tvb_pos = qMin(offset + row_width_, tvb_len) - 1;
     QList<QTextLayout::FormatRange> fmt_list;
 
@@ -407,7 +407,7 @@ void ByteViewText::drawLine(QPainter *painter, const int offset, const int row_y
 
     // Hex
     if (show_hex_) {
-        int ascii_start = line.length() + DataPrinter::hexChars() + 3;
+        int ascii_start = static_cast<int>(line.length()) + DataPrinter::hexChars() + 3;
         // Extra hover space before and after each byte.
         int slop = font_width_ / 2;
 
@@ -676,7 +676,7 @@ void ByteViewText::copyBytes(bool)
 // math easier. Should we do smooth scrolling?
 void ByteViewText::updateScrollbars()
 {
-    const int length = data_.count();
+    const int length = static_cast<int>(data_.count());
     if (length > 0) {
         int all_lines_height = length / row_width_ + ((length % row_width_) ? 1 : 0) - viewport()->height() / line_height_;
 
diff --git a/ui/qt/widgets/display_filter_edit.cpp b/ui/qt/widgets/display_filter_edit.cpp
index ac45de0def..4511b1483d 100644
--- a/ui/qt/widgets/display_filter_edit.cpp
+++ b/ui/qt/widgets/display_filter_edit.cpp
@@ -515,7 +515,7 @@ void DisplayFilterEdit::buildCompletionList(const QString &field_word)
 
     void *proto_cookie;
     QStringList field_list;
-    int field_dots = field_word.count('.'); // Some protocol names (_ws.expert) contain periods.
+    int field_dots = static_cast<int>(field_word.count('.')); // Some protocol names (_ws.expert) contain periods.
     for (int proto_id = proto_get_first_protocol(&proto_cookie); proto_id != -1; proto_id = proto_get_next_protocol(&proto_cookie)) {
         protocol_t *protocol = find_protocol_by_id(proto_id);
         if (!proto_is_protocol_enabled(protocol)) continue;
diff --git a/ui/qt/widgets/field_filter_edit.cpp b/ui/qt/widgets/field_filter_edit.cpp
index c7328375fc..59d12cba51 100644
--- a/ui/qt/widgets/field_filter_edit.cpp
+++ b/ui/qt/widgets/field_filter_edit.cpp
@@ -147,7 +147,7 @@ void FieldFilterEdit::buildCompletionList(const QString &field_word)
 
     void *proto_cookie;
     QStringList field_list;
-    int field_dots = field_word.count('.'); // Some protocol names (_ws.expert) contain periods.
+    int field_dots = static_cast<int>(field_word.count('.')); // Some protocol names (_ws.expert) contain periods.
     for (int proto_id = proto_get_first_protocol(&proto_cookie); proto_id != -1; proto_id = proto_get_next_protocol(&proto_cookie)) {
         protocol_t *protocol = find_protocol_by_id(proto_id);
         if (!proto_is_protocol_enabled(protocol)) continue;
diff --git a/ui/qt/widgets/profile_tree_view.cpp b/ui/qt/widgets/profile_tree_view.cpp
index 8ac415e6b8..67b8ef4aaf 100644
--- a/ui/qt/widgets/profile_tree_view.cpp
+++ b/ui/qt/widgets/profile_tree_view.cpp
@@ -61,9 +61,9 @@ void ProfileTreeView::selectionChanged(const QItemSelection &selected, const QIt
 
     if (model())
     {
-        int offColumn = model()->columnCount();
-        int idxCount = selectedIndexes().count() / offColumn;
-        int dselCount = deselected.count() > 0 ? deselected.at(0).indexes().count() / offColumn : 0;
+        qsizetype offColumn = model()->columnCount();
+        qsizetype idxCount = selectedIndexes().count() / offColumn;
+        qsizetype dselCount = deselected.count() > 0 ? deselected.at(0).indexes().count() / offColumn : 0;
 
         /* Ensure, that the last selected row cannot be deselected */
         if (idxCount == 0 && dselCount == 1)
diff --git a/ui/qt/widgets/qcustomplot.h b/ui/qt/widgets/qcustomplot.h
index 8d313b21d9..32ef017dd6 100644
--- a/ui/qt/widgets/qcustomplot.h
+++ b/ui/qt/widgets/qcustomplot.h
@@ -954,7 +954,7 @@ public:
   friend inline const QCPDataSelection operator-(const QCPDataRange& a, const QCPDataRange& b);
 
   // getters:
-  int dataRangeCount() const { return mDataRanges.size(); }
+  int dataRangeCount() const { return static_cast<int>(mDataRanges.size()); }
   int dataPointCount() const;
   QCPDataRange dataRange(int index=0) const;
   QList<QCPDataRange> dataRanges() const { return mDataRanges; }
@@ -1358,8 +1358,8 @@ public:
   virtual ~QCPLayoutGrid() Q_DECL_OVERRIDE;
 
   // getters:
-  int rowCount() const { return mElements.size(); }
-  int columnCount() const { return mElements.size() > 0 ? mElements.first().size() : 0; }
+  int rowCount() const { return static_cast<int>(mElements.size()); }
+  int columnCount() const { return mElements.size() > 0 ? (int) mElements.first().size() : 0; }
   QList<double> columnStretchFactors() const { return mColumnStretchFactors; }
   QList<double> rowStretchFactors() const { return mRowStretchFactors; }
   int columnSpacing() const { return mColumnSpacing; }
@@ -2568,7 +2568,7 @@ public:
   QCPDataContainer();
 
   // getters:
-  int size() const { return mData.size()-mPreallocSize; }
+  int size() const { return static_cast<int>(mData.size()-mPreallocSize); }
   bool isEmpty() const { return size() == 0; }
   bool autoSqueeze() const { return mAutoSqueeze; }
 
@@ -5695,7 +5695,7 @@ public:
   // non-virtual methods:
   QList<QCPBars*> bars() const { return mBars; }
   QCPBars* bars(int index) const;
-  int size() const { return mBars.size(); }
+  int size() const { return static_cast<int>(mBars.size()); }
   bool isEmpty() const { return mBars.isEmpty(); }
   void clear();
   bool contains(QCPBars *bars) const { return mBars.contains(bars); }