9 files changed, 27 insertions, 24 deletions
diff --git a/demos/spectrum/app/engine.h b/demos/spectrum/app/engine.h
index 21867b3..ab5ae0d 100644
--- a/demos/spectrum/app/engine.h
+++ b/demos/spectrum/app/engine.h
@@ -64,10 +64,11 @@
 #include <QDir>
 #endif
 
-class QAudioInput;
-class QAudioOutput;
 class FrequencySpectrum;
-class QFile;
+
+QT_FORWARD_DECLARE_CLASS(QAudioInput)
+QT_FORWARD_DECLARE_CLASS(QAudioOutput)
+QT_FORWARD_DECLARE_CLASS(QFile)
 
 /**
  * This class interfaces with the QtMultimedia audio classes, and also with
diff --git a/demos/spectrum/app/mainwidget.h b/demos/spectrum/app/mainwidget.h
index 86a47e6..ddab8b7 100644
--- a/demos/spectrum/app/mainwidget.h
+++ b/demos/spectrum/app/mainwidget.h
@@ -53,11 +53,12 @@ class Waveform;
 class LevelMeter;
 class SettingsDialog;
 class ToneGeneratorDialog;
-class QAudioFormat;
-class QLabel;
-class QPushButton;
-class QMenu;
-class QAction;
+
+QT_FORWARD_DECLARE_CLASS(QAudioFormat)
+QT_FORWARD_DECLARE_CLASS(QLabel)
+QT_FORWARD_DECLARE_CLASS(QPushButton)
+QT_FORWARD_DECLARE_CLASS(QMenu)
+QT_FORWARD_DECLARE_CLASS(QAction)
 
 /**
  * Main application widget, responsible for connecting the various UI
diff --git a/demos/spectrum/app/settingsdialog.h b/demos/spectrum/app/settingsdialog.h
index 77b2b61..796b4af 100644
--- a/demos/spectrum/app/settingsdialog.h
+++ b/demos/spectrum/app/settingsdialog.h
@@ -45,11 +45,11 @@
 #include <QDialog>
 #include <QtMultimedia/QAudioDeviceInfo>
 
-class QComboBox;
-class QCheckBox;
-class QSlider;
-class QSpinBox;
-class QGridLayout;
+QT_FORWARD_DECLARE_CLASS(QComboBox)
+QT_FORWARD_DECLARE_CLASS(QCheckBox)
+QT_FORWARD_DECLARE_CLASS(QSlider)
+QT_FORWARD_DECLARE_CLASS(QSpinBox)
+QT_FORWARD_DECLARE_CLASS(QGridLayout)
 
 /**
  * Dialog used to control settings such as the audio input / output device
diff --git a/demos/spectrum/app/spectrograph.h b/demos/spectrum/app/spectrograph.h
index 45db244..ce59d90 100644
--- a/demos/spectrum/app/spectrograph.h
+++ b/demos/spectrum/app/spectrograph.h
@@ -44,7 +44,7 @@
 #include <QWidget>
 #include "frequencyspectrum.h"
 
-class QMouseEvent;
+QT_FORWARD_DECLARE_CLASS(QMouseEvent)
 
 /**
  * Widget which displays a spectrograph showing the frequency spectrum
diff --git a/demos/spectrum/app/spectrumanalyser.h b/demos/spectrum/app/spectrumanalyser.h
index 98d9d84..ab4abe1 100644
--- a/demos/spectrum/app/spectrumanalyser.h
+++ b/demos/spectrum/app/spectrumanalyser.h
@@ -58,8 +58,9 @@
 #include "FFTRealFixLenParam.h"
 #endif
 
-class QAudioFormat;
-class QThread;
+QT_FORWARD_DECLARE_CLASS(QAudioFormat)
+QT_FORWARD_DECLARE_CLASS(QThread)
+
 class FFTRealWrapper;
 
 class SpectrumAnalyserThreadPrivate;
diff --git a/demos/spectrum/app/tonegenerator.h b/demos/spectrum/app/tonegenerator.h
index 0c2f8fd..bf31179 100644
--- a/demos/spectrum/app/tonegenerator.h
+++ b/demos/spectrum/app/tonegenerator.h
@@ -44,8 +44,8 @@
 #include <QtCore/qglobal.h>
 #include "spectrum.h"
 
-class QAudioFormat;
-class QByteArray;
+QT_FORWARD_DECLARE_CLASS(QAudioFormat)
+QT_FORWARD_DECLARE_CLASS(QByteArray)
 
 /**
  * Generate a sine wave
diff --git a/demos/spectrum/app/tonegeneratordialog.h b/demos/spectrum/app/tonegeneratordialog.h
index 2e66706..c2aa892 100644
--- a/demos/spectrum/app/tonegeneratordialog.h
+++ b/demos/spectrum/app/tonegeneratordialog.h
@@ -45,10 +45,10 @@
 #include <QDialog>
 #include <QtMultimedia/QAudioDeviceInfo>
 
-class QCheckBox;
-class QSlider;
-class QSpinBox;
-class QGridLayout;
+QT_FORWARD_DECLARE_CLASS(QCheckBox)
+QT_FORWARD_DECLARE_CLASS(QSlider)
+QT_FORWARD_DECLARE_CLASS(QSpinBox)
+QT_FORWARD_DECLARE_CLASS(QGridLayout)
 
 /**
  * Dialog which controls the parameters of the tone generator.
diff --git a/demos/spectrum/app/utils.h b/demos/spectrum/app/utils.h
index 596533e..4e29030 100644
--- a/demos/spectrum/app/utils.h
+++ b/demos/spectrum/app/utils.h
@@ -44,7 +44,7 @@
 #include <QtCore/qglobal.h>
 #include <QDebug>
 
-class QAudioFormat;
+QT_FORWARD_DECLARE_CLASS(QAudioFormat)
 
 //-----------------------------------------------------------------------------
 // Miscellaneous utility functions
diff --git a/demos/spectrum/app/waveform.h b/demos/spectrum/app/waveform.h
index dce3c37..57c9eec 100644
--- a/demos/spectrum/app/waveform.h
+++ b/demos/spectrum/app/waveform.h
@@ -46,7 +46,7 @@
 #include <QPixmap>
 #include <QScopedPointer>
 
-class QByteArray;
+QT_FORWARD_DECLARE_CLASS(QByteArray)
 
 /**
  * Widget which displays a section of the audio waveform.