AudioIODeviceCallback, AudioBuffer, AudioFormatReader: Use const T* const* for multi-channel data

BREAKING-CHANGES.txt

@@ -4,6 +4,35 @@ JUCE breaking changes
 develop
 =======
 
+Change
+------
+The type representing multi-channel audio data has been changed from T** to
+T* const*. Affected classes are AudioIODeviceCallback, AudioBuffer and
+AudioFormatReader.
+
+Possible Issues
+---------------
+Code overriding the affected AudioIODeviceCallback and AudioFormatReader
+functions will fail to compile. Code that interacts with the return value of
+AudioBuffer::getArrayOfReadPointers() and AudioBuffer::getArrayOfWritePointers()
+may fail to compile.
+
+Workaround
+----------
+Functions overriding the affected AudioIODeviceCallback and AudioFormatReader
+members will need to be changed to confirm to the new signature. Type
+declarations related to getArrayOfReadPointers() and getArrayOfWritePointers()
+of AudioBuffer may have to be adjusted.
+
+Rationale
+---------
+While the previous signature permitted it, changing the channel pointers by the
+previously used types was already being considered illegal. The earlier type
+however prevented passing T** values to parameters with type const T**. In some
+places this necessitated the usage of const_cast. The new signature can bind to
+T** values and the awkward casting can be avoided.
+
+
 Change
 ------
 The minimum supported C++ standard is now C++17 and the oldest supported

examples/Assets/AudioLiveScrollingDisplay.h

@@ -45,8 +45,8 @@ public:
         clear();
     }
 
-    void audioDeviceIOCallback (const float** inputChannelData, int numInputChannels,
+    void audioDeviceIOCallback (const float* const* inputChannelData, int numInputChannels,
-                                float** outputChannelData, int numOutputChannels,
+                                float* const* outputChannelData, int numOutputChannels,
                                 int numberOfSamples) override
     {
         for (int i = 0; i < numberOfSamples; ++i)

examples/Audio/AudioLatencyDemo.h

@@ -136,8 +136,8 @@ public:
 
     void audioDeviceStopped() override {}
 
-    void audioDeviceIOCallback (const float** inputChannelData, int numInputChannels,
+    void audioDeviceIOCallback (const float* const* inputChannelData, int numInputChannels,
-                                float** outputChannelData, int numOutputChannels, int numSamples) override
+                                float* const* outputChannelData, int numOutputChannels, int numSamples) override
     {
         const ScopedLock sl (lock);
 

examples/Audio/AudioRecordingDemo.h

@@ -134,8 +134,8 @@ public:
         sampleRate = 0;
     }
 
-    void audioDeviceIOCallback (const float** inputChannelData, int numInputChannels,
+    void audioDeviceIOCallback (const float* const* inputChannelData, int numInputChannels,
-                                float** outputChannelData, int numOutputChannels,
+                                float* const* outputChannelData, int numOutputChannels,
                                 int numSamples) override
     {
         const ScopedLock sl (writerLock);

examples/Audio/MPEDemo.h

@@ -689,8 +689,8 @@ public:
     }
 
     //==============================================================================
-    void audioDeviceIOCallback (const float** /*inputChannelData*/, int /*numInputChannels*/,
+    void audioDeviceIOCallback (const float* const* /*inputChannelData*/, int /*numInputChannels*/,
-                                float** outputChannelData, int numOutputChannels,
+                                float* const* outputChannelData, int numOutputChannels,
                                 int numSamples) override
     {
         AudioBuffer<float> buffer (outputChannelData, numOutputChannels, numSamples);

modules/juce_audio_basics/buffers/juce_AudioDataConverters.h

@@ -662,7 +662,7 @@ private:
     {
         using ElementType = std::remove_pointer_t<decltype (DataFormat::data)>;
         using ChannelType = std::conditional_t<IsConst, const ElementType*, ElementType*>;
-        using DataType = std::conditional_t<IsInterleaved, ChannelType, ChannelType*>;
+        using DataType = std::conditional_t<IsInterleaved, ChannelType, ChannelType const*>;
         using PointerType = Pointer<DataFormat,
                                     Endianness,
                                     std::conditional_t<IsInterleaved, Interleaved, NonInterleaved>,

modules/juce_audio_basics/buffers/juce_AudioSampleBuffer.h

@@ -324,7 +324,7 @@ public:
         Don't modify any of the pointers that are returned, and bear in mind that
         these will become invalid if the buffer is resized.
     */
-    const Type** getArrayOfReadPointers() const noexcept            { return const_cast<const Type**> (channels); }
+    const Type* const* getArrayOfReadPointers() const noexcept            { return channels; }
 
     /** Returns an array of pointers to the channels in the buffer.
 
@@ -339,7 +339,7 @@ public:
 
         @see setNotClear
     */
-    Type** getArrayOfWritePointers() noexcept                       { isClear = false; return channels; }
+    Type* const* getArrayOfWritePointers() noexcept                       { isClear = false; return channels; }
 
     //==============================================================================
     /** Changes the buffer's size or number of channels.
@@ -465,7 +465,7 @@ public:
         @param newNumSamples    the number of samples to use - this must correspond to the
                                 size of the arrays passed in
     */
-    void setDataToReferTo (Type** dataToReferTo,
+    void setDataToReferTo (Type* const* dataToReferTo,
                            int newNumChannels,
                            int newStartSample,
                            int newNumSamples)
@@ -506,7 +506,7 @@ public:
         @param newNumSamples    the number of samples to use - this must correspond to the
                                 size of the arrays passed in
     */
-    void setDataToReferTo (Type** dataToReferTo,
+    void setDataToReferTo (Type* const* dataToReferTo,
                            int newNumChannels,
                            int newNumSamples)
     {

modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.cpp

@@ -69,9 +69,9 @@ public:
     CallbackHandler (AudioDeviceManager& adm) noexcept  : owner (adm) {}
 
 private:
-    void audioDeviceIOCallbackWithContext (const float** ins,
+    void audioDeviceIOCallbackWithContext (const float* const* ins,
                                            int numIns,
-                                           float** outs,
+                                           float* const* outs,
                                            int numOuts,
                                            int numSamples,
                                            const AudioIODeviceCallbackContext& context) override
@@ -982,9 +982,9 @@ void AudioDeviceManager::removeAudioCallback (AudioIODeviceCallback* callbackToR
     }
 }
 
-void AudioDeviceManager::audioDeviceIOCallbackInt (const float** inputChannelData,
+void AudioDeviceManager::audioDeviceIOCallbackInt (const float* const* inputChannelData,
                                                    int numInputChannels,
-                                                   float** outputChannelData,
+                                                   float* const* outputChannelData,
                                                    int numOutputChannels,
                                                    int numSamples,
                                                    const AudioIODeviceCallbackContext& context)
@@ -1006,7 +1006,7 @@ void AudioDeviceManager::audioDeviceIOCallbackInt (const float** inputChannelDat
                                                                      numSamples,
                                                                      context);
 
-        auto** tempChans = tempBuffer.getArrayOfWritePointers();
+        auto* const* tempChans = tempBuffer.getArrayOfWritePointers();
 
         for (int i = callbacks.size(); --i > 0;)
         {
@@ -1048,7 +1048,7 @@ void AudioDeviceManager::audioDeviceIOCallbackInt (const float** inputChannelDat
             testSound.reset();
     }
 
-    outputLevelGetter->updateLevel (const_cast<const float**> (outputChannelData), numOutputChannels, numSamples);
+    outputLevelGetter->updateLevel (outputChannelData, numOutputChannels, numSamples);
 }
 
 void AudioDeviceManager::audioDeviceAboutToStartInt (AudioIODevice* const device)
@@ -1891,7 +1891,7 @@ private:
         std::function<void()> stopped;
         std::function<void()> error;
 
-        void audioDeviceIOCallback (const float**, int, float**, int, int) override { NullCheckedInvocation::invoke (callback); }
+        void audioDeviceIOCallback (const float* const*, int, float* const*, int, int) override { NullCheckedInvocation::invoke (callback); }
         void audioDeviceAboutToStart (AudioIODevice*)                                  override { NullCheckedInvocation::invoke (aboutToStart); }
         void audioDeviceStopped()                                                      override { NullCheckedInvocation::invoke (stopped); }
         void audioDeviceError (const String&)                                          override { NullCheckedInvocation::invoke (error); }

modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.h

@@ -526,9 +526,9 @@ private:
     class CallbackHandler;
     std::unique_ptr<CallbackHandler> callbackHandler;
 
-    void audioDeviceIOCallbackInt (const float** inputChannelData,
+    void audioDeviceIOCallbackInt (const float* const* inputChannelData,
                                    int totalNumInputChannels,
-                                   float** outputChannelData,
+                                   float* const* outputChannelData,
                                    int totalNumOutputChannels,
                                    int numSamples,
                                    const AudioIODeviceCallbackContext& context);

modules/juce_audio_devices/audio_io/juce_AudioIODevice.h

@@ -91,9 +91,9 @@ public:
                                     performance. So make sure your code can cope with reasonable
                                     changes in the buffer size from one callback to the next.
     */
-    virtual void audioDeviceIOCallback (const float** inputChannelData,
+    virtual void audioDeviceIOCallback (const float* const* inputChannelData,
                                         int numInputChannels,
-                                        float** outputChannelData,
+                                        float* const* outputChannelData,
                                         int numOutputChannels,
                                         int numSamples)
     {
@@ -105,9 +105,9 @@ public:
         The default implementation of this function will call audioDeviceIOCallback(),
         but you can override this function if you need to make use of the context information.
     */
-    virtual void audioDeviceIOCallbackWithContext (const float** inputChannelData,
+    virtual void audioDeviceIOCallbackWithContext (const float* const* inputChannelData,
                                                    int numInputChannels,
-                                                   float** outputChannelData,
+                                                   float* const* outputChannelData,
                                                    int numOutputChannels,
                                                    int numSamples,
                                                    const AudioIODeviceCallbackContext& context)

modules/juce_audio_devices/native/juce_android_Oboe.cpp

@@ -423,8 +423,8 @@ private:
         }
     }
 
-    void process (const float** inputChannelData, int numInputChannels,
+    void process (const float* const* inputChannelData, int numInputChannels,
-                  float** outputChannelData, int numOutputChannels, int32_t numFrames)
+                  float* const* outputChannelData, int numOutputChannels, int32_t numFrames)
     {
         if (auto* cb = callback.exchange (nullptr))
         {

modules/juce_audio_devices/native/juce_ios_Audio.cpp

@@ -892,8 +892,8 @@ struct iOSAudioIODevice::Pimpl      : public AsyncUpdater
             if ((int) numFrames > channelData.getFloatBufferSize())
                 channelData.setFloatBufferSize ((int) numFrames);
 
-            float** const inputData = channelData.audioData.getArrayOfWritePointers();
+            float* const* const inputData = channelData.audioData.getArrayOfWritePointers();
-            float** const outputData = inputData + channelData.inputs->numActiveChannels;
+            float* const* const outputData = inputData + channelData.inputs->numActiveChannels;
 
             if (useInput)
             {

modules/juce_audio_devices/native/juce_linux_JackAudio.cpp

@@ -462,7 +462,7 @@ private:
         if (callback != nullptr)
         {
             if ((numActiveInChans + numActiveOutChans) > 0)
-                callback->audioDeviceIOCallbackWithContext (const_cast<const float**> (inChans.getData()),
+                callback->audioDeviceIOCallbackWithContext (inChans.getData(),
                                                             numActiveInChans,
                                                             outChans,
                                                             numActiveOutChans,

modules/juce_audio_devices/native/juce_mac_CoreAudio.cpp

@@ -852,7 +852,7 @@ public:
 
             const auto nanos = timeStamp != nullptr ? timeConversions.hostTimeToNanos (timeStamp->mHostTime) : 0;
 
-            callback->audioDeviceIOCallbackWithContext (const_cast<const float**> (tempInputBuffers.get()),
+            callback->audioDeviceIOCallbackWithContext (tempInputBuffers.get(),
                                                         numInputChans,
                                                         tempOutputBuffers,
                                                         numOutputChans,
@@ -1685,8 +1685,8 @@ private:
     bool active = false;
     String lastError;
     AudioBuffer<float> fifos;
-    const float** fifoReadPointers = nullptr;
+    const float* const* fifoReadPointers = nullptr;
-    float** fifoWritePointers = nullptr;
+    float* const* fifoWritePointers = nullptr;
     WaitableEvent threadInitialised;
     CriticalSection closeLock;
 
@@ -2032,9 +2032,9 @@ private:
             outputFifo.finishedWrite (size1 + size2);
         }
 
-        void audioDeviceIOCallbackWithContext (const float** inputChannelData,
+        void audioDeviceIOCallbackWithContext (const float* const* inputChannelData,
                                                int numInputChannels,
-                                               float** outputChannelData,
+                                               float* const* outputChannelData,
                                                int numOutputChannels,
                                                int numSamples,
                                                const AudioIODeviceCallbackContext&) override

modules/juce_audio_devices/native/juce_win32_ASIO.cpp

@@ -1326,7 +1326,7 @@ private:
                     inputFormat[i].convertToFloat (infos[i].buffers[bufferIndex], inBuffers[i], samps);
                 }
 
-                currentCallback->audioDeviceIOCallbackWithContext (const_cast<const float**> (inBuffers.getData()),
+                currentCallback->audioDeviceIOCallbackWithContext (inBuffers.getData(),
                                                                    numActiveInputChans,
                                                                    outBuffers,
                                                                    numActiveOutputChans,

modules/juce_audio_devices/native/juce_win32_WASAPI.cpp

@@ -1552,7 +1552,7 @@ public:
                 const ScopedTryLock sl (startStopLock);
 
                 if (sl.isLocked() && isStarted)
-                    callback->audioDeviceIOCallbackWithContext (const_cast<const float**> (inputBuffers),
+                    callback->audioDeviceIOCallbackWithContext (inputBuffers,
                                                                 numInputBuffers,
                                                                 outputBuffers,
                                                                 numOutputBuffers,
@@ -1566,7 +1566,7 @@ public:
             {
                 // Note that this function is handed the input device so it can check for the event and make sure
                 // the input reservoir is filled up correctly even when bufferSize > device actualBufferSize
-                outputDevice->copyBuffers (const_cast<const float**> (outputBuffers), numOutputBuffers, bufferSize, inputDevice.get(), *this);
+                outputDevice->copyBuffers (outputBuffers, numOutputBuffers, bufferSize, inputDevice.get(), *this);
 
                 if (outputDevice->sampleRateHasChanged)
                 {

modules/juce_audio_devices/sources/juce_AudioSourcePlayer.cpp

@@ -56,9 +56,9 @@ void AudioSourcePlayer::setGain (const float newGain) noexcept
     gain = newGain;
 }
 
-void AudioSourcePlayer::audioDeviceIOCallback (const float** inputChannelData,
+void AudioSourcePlayer::audioDeviceIOCallback (const float* const* inputChannelData,
                                                int totalNumInputChannels,
-                                               float** outputChannelData,
+                                               float* const* outputChannelData,
                                                int totalNumOutputChannels,
                                                int numSamples)
 {

modules/juce_audio_devices/sources/juce_AudioSourcePlayer.h

@@ -80,9 +80,9 @@ public:
 
     //==============================================================================
     /** Implementation of the AudioIODeviceCallback method. */
-    void audioDeviceIOCallback (const float** inputChannelData,
+    void audioDeviceIOCallback (const float* const* inputChannelData,
                                 int totalNumInputChannels,
-                                float** outputChannelData,
+                                float* const* outputChannelData,
                                 int totalNumOutputChannels,
                                 int numSamples) override;
 

modules/juce_audio_formats/codecs/juce_AiffAudioFormat.cpp

@@ -573,7 +573,7 @@ public:
     }
 
     //==============================================================================
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         clearSamplesBeyondAvailableLength (destSamples, numDestChannels, startOffsetInDestBuffer,
@@ -829,7 +829,7 @@ public:
     {
     }
 
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         clearSamplesBeyondAvailableLength (destSamples, numDestChannels, startOffsetInDestBuffer,

modules/juce_audio_formats/codecs/juce_CoreAudioFormat.cpp

@@ -502,7 +502,7 @@ public:
     }
 
     //==============================================================================
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         clearSamplesBeyondAvailableLength (destSamples, numDestChannels, startOffsetInDestBuffer,

modules/juce_audio_formats/codecs/juce_FlacAudioFormat.cpp

@@ -230,7 +230,7 @@ public:
         reservoir.setSize ((int) numChannels, 2 * (int) info.max_blocksize, false, false, true);
     }
 
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         if (! ok)

modules/juce_audio_formats/codecs/juce_MP3AudioFormat.cpp

@@ -2975,7 +2975,7 @@ public:
         }
     }
 
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         if (destSamples == nullptr)
@@ -3033,7 +3033,7 @@ public:
             }
 
             const int numToCopy = jmin (decodedEnd - decodedStart, numSamples);
-            float* const* const dst = reinterpret_cast<float**> (destSamples);
+            float* const* const dst = reinterpret_cast<float* const*> (destSamples);
             memcpy (dst[0] + startOffsetInDestBuffer, decoded0 + decodedStart, (size_t) numToCopy * sizeof (float));
 
             if (numDestChannels > 1 && dst[1] != nullptr)

modules/juce_audio_formats/codecs/juce_OggVorbisAudioFormat.cpp

@@ -158,7 +158,7 @@ public:
     }
 
     //==============================================================================
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         const auto getBufferedRange = [this] { return bufferedRange; };

modules/juce_audio_formats/codecs/juce_WavAudioFormat.cpp

@@ -1476,7 +1476,7 @@ public:
     }
 
     //==============================================================================
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         clearSamplesBeyondAvailableLength (destSamples, numDestChannels, startOffsetInDestBuffer,
@@ -1852,7 +1852,7 @@ public:
     {
     }
 
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         clearSamplesBeyondAvailableLength (destSamples, numDestChannels, startOffsetInDestBuffer,

modules/juce_audio_formats/codecs/juce_WindowsMediaAudioFormat.cpp

@@ -163,7 +163,7 @@ public:
             wmSyncReader->Close();
     }
 
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         if (sampleRate <= 0)

modules/juce_audio_formats/format/juce_ARAAudioReaders.cpp

@@ -115,7 +115,7 @@ void ARAAudioSourceReader::willDestroyAudioSource (ARAAudioSource* audioSource)
     invalidate();
 }
 
-bool ARAAudioSourceReader::readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+bool ARAAudioSourceReader::readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                                         int64 startSampleInFile, int numSamples)
 {
     const auto destSize = (bitsPerSample / 8) * (size_t) numSamples;
@@ -237,7 +237,7 @@ void ARAPlaybackRegionReader::invalidate()
     playbackRenderer.reset();
 }
 
-bool ARAPlaybackRegionReader::readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+bool ARAPlaybackRegionReader::readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                                            int64 startSampleInFile, int numSamples)
 {
     bool success = false;

modules/juce_audio_formats/format/juce_ARAAudioReaders.h

@@ -83,7 +83,7 @@ public:
 
     ~ARAAudioSourceReader() override;
 
-    bool readSamples (int** destSamples,
+    bool readSamples (int* const* destSamples,
                       int numDestChannels,
                       int startOffsetInDestBuffer,
                       int64 startSampleInFile,
@@ -166,7 +166,7 @@ public:
     */
     void invalidate();
 
-    bool readSamples (int** destSamples,
+    bool readSamples (int* const* destSamples,
                       int numDestChannels,
                       int startOffsetInDestBuffer,
                       int64 startSampleInFile,

modules/juce_audio_formats/format/juce_AudioFormatReader.cpp

@@ -86,7 +86,7 @@ bool AudioFormatReader::read (int* const* destChannels,
     if (numSamplesToRead <= 0)
         return true;
 
-    if (! readSamples (const_cast<int**> (destChannels),
+    if (! readSamples (destChannels,
                        jmin ((int) numChannels, numDestChannels), startOffsetInDestBuffer,
                        startSampleInSource, numSamplesToRead))
         return false;

modules/juce_audio_formats/format/juce_AudioFormatReader.h

@@ -267,7 +267,7 @@ public:
                                          to begin reading. This value is guaranteed to be >= 0.
         @param numSamples                the number of samples to read
     */
-    virtual bool readSamples (int** destChannels,
+    virtual bool readSamples (int* const* destChannels,
                               int numDestChannels,
                               int startOffsetInDestBuffer,
                               int64 startSampleInFile,
@@ -306,7 +306,7 @@ protected:
     /** Used by AudioFormatReader subclasses to clear any parts of the data blocks that lie
         beyond the end of their available length.
     */
-    static void clearSamplesBeyondAvailableLength (int** destChannels, int numDestChannels,
+    static void clearSamplesBeyondAvailableLength (int* const* destChannels, int numDestChannels,
                                                    int startOffsetInDestBuffer, int64 startSampleInFile,
                                                    int& numSamples, int64 fileLengthInSamples)
     {

modules/juce_audio_formats/format/juce_AudioSubsectionReader.cpp

@@ -50,7 +50,7 @@ AudioSubsectionReader::~AudioSubsectionReader()
 }
 
 //==============================================================================
-bool AudioSubsectionReader::readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+bool AudioSubsectionReader::readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                                          int64 startSampleInFile, int numSamples)
 {
     clearSamplesBeyondAvailableLength (destSamples, numDestChannels, startOffsetInDestBuffer,

modules/juce_audio_formats/format/juce_AudioSubsectionReader.h

@@ -66,7 +66,7 @@ public:
 
 
     //==============================================================================
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override;
 
     void readMaxLevels (int64 startSample, int64 numSamples,

modules/juce_audio_formats/format/juce_BufferingAudioFormatReader.cpp

@@ -53,7 +53,7 @@ void BufferingAudioReader::setReadTimeout (int timeoutMilliseconds) noexcept
     timeoutMs = timeoutMilliseconds;
 }
 
-bool BufferingAudioReader::readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+bool BufferingAudioReader::readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                                         int64 startSampleInFile, int numSamples)
 {
     auto startTime = Time::getMillisecondCounter();
@@ -218,7 +218,7 @@ struct TestAudioFormatReader  : public AudioFormatReader
         numChannels           = (unsigned int) buffer.getNumChannels();
     }
 
-    bool readSamples (int** destChannels, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destChannels, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override
     {
         clearSamplesBeyondAvailableLength (destChannels, numDestChannels, startOffsetInDestBuffer,
@@ -270,7 +270,7 @@ public:
                     numChannels           = 2;
                 }
 
-                bool readSamples (int**, int, int, int64, int) override
+                bool readSamples (int* const*, int, int, int64, int) override
                 {
                     Thread::sleep (100);
                     return true;

modules/juce_audio_formats/format/juce_BufferingAudioFormatReader.h

@@ -63,7 +63,7 @@ public:
     void setReadTimeout (int timeoutMilliseconds) noexcept;
 
     //==============================================================================
-    bool readSamples (int** destSamples, int numDestChannels, int startOffsetInDestBuffer,
+    bool readSamples (int* const* destSamples, int numDestChannels, int startOffsetInDestBuffer,
                       int64 startSampleInFile, int numSamples) override;
 
 private:

modules/juce_audio_plugin_client/LV2/juce_LV2_Client.cpp

@@ -484,7 +484,7 @@ public:
     template<typename UnaryFunction>
     static void iterateAudioBuffer (AudioBuffer<float>& ab, UnaryFunction fn)
     {
-        float** sampleData = ab.getArrayOfWritePointers();
+        float* const* sampleData = ab.getArrayOfWritePointers();
 
         for (int c = ab.getNumChannels(); --c >= 0;)
             for (int s = ab.getNumSamples(); --s >= 0;)

modules/juce_audio_plugin_client/Standalone/juce_StandaloneFilterWindow.h

@@ -448,9 +448,9 @@ private:
             inner.audioDeviceAboutToStart (device);
         }
 
-        void audioDeviceIOCallbackWithContext (const float** inputChannelData,
+        void audioDeviceIOCallbackWithContext (const float* const* inputChannelData,
                                                int numInputChannels,
-                                               float** outputChannelData,
+                                               float* const* outputChannelData,
                                                int numOutputChannels,
                                                int numSamples,
                                                const AudioIODeviceCallbackContext& context) override
@@ -600,9 +600,9 @@ private:
     };
 
     //==============================================================================
-    void audioDeviceIOCallbackWithContext (const float** inputChannelData,
+    void audioDeviceIOCallbackWithContext (const float* const* inputChannelData,
                                            int numInputChannels,
-                                           float** outputChannelData,
+                                           float* const* outputChannelData,
                                            int numOutputChannels,
                                            int numSamples,
                                            const AudioIODeviceCallbackContext& context) override

modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp

@@ -829,6 +829,34 @@ static const int defaultVSTBlockSizeValue = 512;
 
 JUCE_BEGIN_IGNORE_WARNINGS_MSVC (4996)
 
+class TempChannelPointers
+{
+public:
+    template <typename T>
+    auto getArrayOfModifiableWritePointers (AudioBuffer<T>& buffer)
+    {
+        auto& pointers = getPointers (Tag<T>{});
+
+        jassert ((int) pointers.size() < buffer.getNumChannels());
+        pointers.resize (jmax (pointers.size(), (size_t) buffer.getNumChannels()));
+
+        std::copy (buffer.getArrayOfWritePointers(),
+                   buffer.getArrayOfWritePointers() + buffer.getNumChannels(),
+                   pointers.begin());
+
+        return pointers.data();
+    }
+
+private:
+    template <typename> struct Tag {};
+
+    auto& getPointers (Tag<float>)  { return floatPointers; }
+    auto& getPointers (Tag<double>) { return doublePointers; }
+
+    std::vector<float*>  floatPointers  { 128 };
+    std::vector<double*> doublePointers { 128 };
+};
+
 //==============================================================================
 struct VSTPluginInstance final   : public AudioPluginInstance,
                                    private Timer,
@@ -2026,6 +2054,7 @@ private:
     bool lastProcessBlockCallWasBypass = false, vstSupportsBypass = false;
     mutable StringArray programNames;
     AudioBuffer<float> outOfPlaceBuffer;
+    TempChannelPointers tempChannelPointers[2];
 
     CriticalSection midiInLock;
     MidiBuffer incomingMidi;
@@ -2456,16 +2485,16 @@ private:
     {
         if ((vstEffect->flags & Vst2::effFlagsCanReplacing) != 0)
         {
-            vstEffect->processReplacing (vstEffect, buffer.getArrayOfWritePointers(),
+            vstEffect->processReplacing (vstEffect, tempChannelPointers[0].getArrayOfModifiableWritePointers (buffer),
-                                                    buffer.getArrayOfWritePointers(), sampleFrames);
+                                                    tempChannelPointers[1].getArrayOfModifiableWritePointers (buffer), sampleFrames);
         }
         else
         {
             outOfPlaceBuffer.setSize (vstEffect->numOutputs, sampleFrames);
             outOfPlaceBuffer.clear();
 
-            vstEffect->process (vstEffect, buffer.getArrayOfWritePointers(),
+            vstEffect->process (vstEffect, tempChannelPointers[0].getArrayOfModifiableWritePointers (buffer),
-                                           outOfPlaceBuffer.getArrayOfWritePointers(), sampleFrames);
+                                           tempChannelPointers[1].getArrayOfModifiableWritePointers (outOfPlaceBuffer), sampleFrames);
 
             for (int i = vstEffect->numOutputs; --i >= 0;)
                 buffer.copyFrom (i, 0, outOfPlaceBuffer.getReadPointer (i), sampleFrames);
@@ -2474,8 +2503,8 @@ private:
 
     inline void invokeProcessFunction (AudioBuffer<double>& buffer, int32 sampleFrames)
     {
-        vstEffect->processDoubleReplacing (vstEffect, buffer.getArrayOfWritePointers(),
+        vstEffect->processDoubleReplacing (vstEffect, tempChannelPointers[0].getArrayOfModifiableWritePointers (buffer),
-                                                      buffer.getArrayOfWritePointers(), sampleFrames);
+                                                      tempChannelPointers[1].getArrayOfModifiableWritePointers (buffer), sampleFrames);
     }
 
     //==============================================================================

modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp

@@ -444,7 +444,7 @@ struct GraphRenderSequence
 
     struct Context
     {
-        FloatType** audioBuffers;
+        FloatType* const* audioBuffers;
         MidiBuffer* midiBuffers;
         AudioPlayHead* audioPlayHead;
         int numSamples;

modules/juce_audio_utils/gui/juce_AudioVisualiserComponent.cpp

@@ -119,7 +119,7 @@ void AudioVisualiserComponent::clear()
         c->clear();
 }
 
-void AudioVisualiserComponent::pushBuffer (const float** d, int numChannels, int num)
+void AudioVisualiserComponent::pushBuffer (const float* const* d, int numChannels, int num)
 {
     numChannels = jmin (numChannels, channels.size());
 

modules/juce_audio_utils/gui/juce_AudioVisualiserComponent.h

@@ -87,7 +87,7 @@ public:
         The number of channels provided here is expected to match the number of channels
         that this AudioVisualiserComponent has been told to use.
     */
-    void pushBuffer (const float** channelData, int numChannels, int numSamples);
+    void pushBuffer (const float* const* channelData, int numChannels, int numSamples);
 
     /** Pushes a single sample (per channel).
         The number of channels provided here is expected to match the number of channels

modules/juce_audio_utils/players/juce_AudioProcessorPlayer.cpp

@@ -30,10 +30,10 @@ template <typename Value>
 struct ChannelInfo
 {
     ChannelInfo() = default;
-    ChannelInfo (Value** dataIn, int numChannelsIn)
+    ChannelInfo (Value* const* dataIn, int numChannelsIn)
         : data (dataIn), numChannels (numChannelsIn)  {}
 
-    Value** data = nullptr;
+    Value* const* data = nullptr;
     int numChannels = 0;
 };
 
@@ -235,9 +235,9 @@ void AudioProcessorPlayer::setMidiOutput (MidiOutput* midiOutputToUse)
 }
 
 //==============================================================================
-void AudioProcessorPlayer::audioDeviceIOCallbackWithContext (const float** const inputChannelData,
+void AudioProcessorPlayer::audioDeviceIOCallbackWithContext (const float* const* const inputChannelData,
                                                              const int numInputChannels,
-                                                             float** const outputChannelData,
+                                                             float* const* const outputChannelData,
                                                              const int numOutputChannels,
                                                              const int numSamples,
                                                              const AudioIODeviceCallbackContext& context)

modules/juce_audio_utils/players/juce_AudioProcessorPlayer.h

@@ -92,7 +92,7 @@ public:
 
     //==============================================================================
     /** @internal */
-    void audioDeviceIOCallbackWithContext (const float**, int, float**, int, int, const AudioIODeviceCallbackContext&) override;
+    void audioDeviceIOCallbackWithContext (const float* const*, int, float* const*, int, int, const AudioIODeviceCallbackContext&) override;
     /** @internal */
     void audioDeviceAboutToStart (AudioIODevice*) override;
     /** @internal */

modules/juce_audio_utils/players/juce_SoundPlayer.cpp

@@ -242,9 +242,9 @@ void SoundPlayer::playTestSound()
 }
 
 //==============================================================================
-void SoundPlayer::audioDeviceIOCallback (const float** inputChannelData,
+void SoundPlayer::audioDeviceIOCallback (const float* const* inputChannelData,
                                          int numInputChannels,
-                                         float** outputChannelData,
+                                         float* const* outputChannelData,
                                          int numOutputChannels,
                                          int numSamples)
 {

modules/juce_audio_utils/players/juce_SoundPlayer.h

@@ -110,7 +110,7 @@ public:
 
     //==============================================================================
     /** @internal */
-    void audioDeviceIOCallback (const float**, int, float**, int, int) override;
+    void audioDeviceIOCallback (const float* const*, int, float* const*, int, int) override;
     /** @internal */
     void audioDeviceAboutToStart (AudioIODevice*) override;
     /** @internal */

modules/juce_dsp/frequency/juce_Convolution_test.cpp

@@ -62,7 +62,7 @@ class ConvolutionTest  : public UnitTest
         AudioBuffer<float> result (2, length);
         result.clear();
 
-        auto** channels = result.getArrayOfWritePointers();
+        auto* const* channels = result.getArrayOfWritePointers();
         std::for_each (channels, channels + result.getNumChannels(), [length] (auto* channel)
         {
             std::fill (channel, channel + length, 1.0f);