Convert to C++17 attribute for unused variables. (other libs)

This cleans up the code a little bit by tying the "unused" attribute
directly to the variable declaration, instead of having some later
statement that pretends to use the variable.  E.G. "(void)x;" and
"Q_UNUSED(x);"

mythtv/libs/libmyth/audio/audiooutput.cpp

@@ -76,7 +76,7 @@ AudioOutput *AudioOutput::OpenAudio(
 }
 
 AudioOutput *AudioOutput::OpenAudio(AudioSettings &settings,
-                                    bool willsuspendpa)
+                                    [[maybe_unused]] bool willsuspendpa)
 {
     QString &main_device = settings.m_mainDevice;
     AudioOutput *ret = nullptr;
@@ -150,9 +150,6 @@ AudioOutput *AudioOutput::OpenAudio(AudioSettings &settings,
             pulsestatus = PulseHandler::Suspend(PulseHandler::kPulseSuspend);
         }
     }
-#else // !USING_PULSE
-    // Quiet warning error when not compiling with pulseaudio
-    Q_UNUSED(willsuspendpa);
 #endif // USING_PULSE
 
     if (main_device.startsWith("ALSA:"))

mythtv/libs/libmyth/audio/audiooutputbase.cpp

@@ -114,11 +114,6 @@ AudioOutputBase::~AudioOutputBase()
     assert(m_memoryCorruptionTest1 == 0xdeadbeef);
     assert(m_memoryCorruptionTest2 == 0xdeadbeef);
     assert(m_memoryCorruptionTest3 == 0xdeadbeef);
-#else
-    Q_UNUSED(m_memoryCorruptionTest0);
-    Q_UNUSED(m_memoryCorruptionTest1);
-    Q_UNUSED(m_memoryCorruptionTest2);
-    Q_UNUSED(m_memoryCorruptionTest3);
 #endif
 }
 

mythtv/libs/libmyth/audio/audiooutputbase.h

@@ -284,17 +284,17 @@ class AudioOutputBase : public AudioOutput, public MThread
 
     // All actual buffers
     SRC_DATA          m_srcData                           {};
-    uint              m_memoryCorruptionTest0             {0xdeadbeef};
+    [[maybe_unused]] uint m_memoryCorruptionTest0         {0xdeadbeef};
     alignas(16) std::array<float,kAudioSRCInputSize> m_srcInBuf {};
-    uint              m_memoryCorruptionTest1             {0xdeadbeef};;
+    [[maybe_unused]] uint m_memoryCorruptionTest1         {0xdeadbeef};;
     float            *m_srcOut                            {nullptr};
     int               m_kAudioSRCOutputSize               {0};
-    uint              m_memoryCorruptionTest2             {0xdeadbeef};;
+    [[maybe_unused]] uint m_memoryCorruptionTest2         {0xdeadbeef};;
     /**
      * main audio buffer
      */
     std::array<uchar,kAudioRingBufferSize> m_audioBuffer  {0};
-    uint              m_memoryCorruptionTest3             {0xdeadbeef};;
+    [[maybe_unused]] uint m_memoryCorruptionTest3         {0xdeadbeef};;
     bool              m_configureSucceeded                {false};
     std::chrono::milliseconds m_lengthLastData            {0ms};
 

mythtv/libs/libmyth/audio/audiooutputca.cpp

@@ -395,10 +395,9 @@ bool AudioOutputCA::RenderAudio(unsigned char *aubuf,
 }
 
 // unneeded and unused in CA
-void AudioOutputCA::WriteAudio(unsigned char *aubuf, int size)
+void AudioOutputCA::WriteAudio([[maybe_unused]] unsigned char *aubuf,
+                               [[maybe_unused]] int size)
 {
-    (void)aubuf;
-    (void)size;
 }
 
 int AudioOutputCA::GetBufferedOnSoundcard(void) const
@@ -427,13 +426,10 @@ std::chrono::milliseconds AudioOutputCA::GetAudiotime(void)
 OSStatus RenderCallbackAnalog(void                       *inRefCon,
                               AudioUnitRenderActionFlags *ioActionFlags,
                               const AudioTimeStamp       *inTimeStamp,
-                              UInt32                     inBusNumber,
-                              UInt32                     inNumberFrames,
+                              [[maybe_unused]] UInt32     inBusNumber,
+                              [[maybe_unused]] UInt32     inNumberFrames,
                               AudioBufferList            *ioData)
 {
-    (void)inBusNumber;
-    (void)inNumberFrames;
-
     AudioOutputCA *inst = (static_cast<CoreAudioData *>(inRefCon))->mCA;
 
     if (!inst->RenderAudio((unsigned char *)(ioData->mBuffers[0].mData),
@@ -447,10 +443,9 @@ OSStatus RenderCallbackAnalog(void                       *inRefCon,
     return noErr;
 }
 
-int AudioOutputCA::GetVolumeChannel(int channel) const
+int AudioOutputCA::GetVolumeChannel([[maybe_unused]] int channel) const
 {
     // FIXME: this only returns global volume
-    (void)channel;
     Float32 volume;
 
     if (!AudioUnitGetParameter(d->mOutputUnit,
@@ -461,19 +456,18 @@ int AudioOutputCA::GetVolumeChannel(int channel) const
     return 0;    // error case
 }
 
-void AudioOutputCA::SetVolumeChannel(int channel, int volume)
+void AudioOutputCA::SetVolumeChannel([[maybe_unused]] int channel, int volume)
 {
     // FIXME: this only sets global volume
-    (void)channel;
     AudioUnitSetParameter(d->mOutputUnit, kHALOutputParam_Volume,
                           kAudioUnitScope_Global, 0, (volume * 0.01F), 0);
 }
 
 // IOProc style callback for SPDIF audio output
-static OSStatus RenderCallbackSPDIF(AudioDeviceID        inDevice,
-                                    const AudioTimeStamp *inNow,
-                                    const void           *inInputData,
-                                    const AudioTimeStamp *inInputTime,
+static OSStatus RenderCallbackSPDIF([[maybe_unused]] AudioDeviceID        inDevice,
+                                    [[maybe_unused]] const AudioTimeStamp *inNow,
+                                    [[maybe_unused]] const void           *inInputData,
+                                    [[maybe_unused]] const AudioTimeStamp *inInputTime,
                                     AudioBufferList      *outOutputData,
                                     const AudioTimeStamp *inOutputTime,
                                     void                 *inRefCon)
@@ -482,11 +476,6 @@ static OSStatus RenderCallbackSPDIF(AudioDeviceID        inDevice,
     AudioOutputCA    *a = d->mCA;
     int           index = d->mStreamIndex;
 
-    (void)inDevice;     // unused
-    (void)inNow;        // unused
-    (void)inInputData;  // unused
-    (void)inInputTime;  // unused
-
     /*
      * HACK: No idea why this would be the case, but after the second run, we get
      * incorrect value

mythtv/libs/libmyth/audio/audiooutputdx.cpp

@@ -129,21 +129,19 @@ using LPFNDSE = HRESULT (WINAPI *) (LPDSENUMCALLBACK, LPVOID);
 #ifdef UNICODE
 int CALLBACK AudioOutputDXPrivate::DSEnumCallback(LPGUID  lpGuid,
                                                   LPCWSTR lpcstrDesc,
-                                                  LPCWSTR lpcstrModule,
+                                 [[maybe_unused]] LPCWSTR lpcstrModule,
                                                   LPVOID  lpContext)
 {
         QString enum_desc = QString::fromWCharArray( lpcstrDesc );
 #else
 int CALLBACK AudioOutputDXPrivate::DSEnumCallback(LPGUID lpGuid,
                                                   LPCSTR lpcstrDesc,
-                                                  LPCSTR lpcstrModule,
+                                 [[maybe_unused]] LPCSTR lpcstrModule,
                                                   LPVOID lpContext)
 {
         QString enum_desc = QString::fromLocal8Bit( lpcstrDesc );
 
 #endif
-    Q_UNUSED(lpcstrModule);
-
     AudioOutputDXPrivate *context = static_cast<AudioOutputDXPrivate*>(lpContext);
     const QString cfg_desc  = context->m_device_name;
     const int device_num    = context->m_device_num;
@@ -576,10 +574,8 @@ int AudioOutputDX::GetBufferedOnSoundcard(void) const
     return buffered;
 }
 
-int AudioOutputDX::GetVolumeChannel(int channel) const
+int AudioOutputDX::GetVolumeChannel([[maybe_unused]] int channel) const
 {
-    Q_UNUSED(channel);
-
     HRESULT dsresult;
     long dxVolume = 0;
     int volume;
@@ -600,10 +596,8 @@ int AudioOutputDX::GetVolumeChannel(int channel) const
     return volume;
 }
 
-void AudioOutputDX::SetVolumeChannel(int channel, int volume)
+void AudioOutputDX::SetVolumeChannel([[maybe_unused]] int channel, int volume)
 {
-    Q_UNUSED(channel);
-
     HRESULT dsresult;
     long dxVolume { DSBVOLUME_MIN };
     if (volume > 0)

mythtv/libs/libmyth/audio/audiooutputjack.cpp

@@ -554,10 +554,9 @@ void AudioOutputJACK::StopOutputThread(void)
 }
 
 // Don't need WriteAudio - this is only for the base class audio loop
-void AudioOutputJACK::WriteAudio(unsigned char *aubuf, int size)
+void AudioOutputJACK::WriteAudio([[maybe_unused]] unsigned char *aubuf,
+                                 [[maybe_unused]] int size)
 {
-    (void)aubuf;
-    (void)size;
     // unneeded and unused in JACK
 }
 

mythtv/libs/libmyth/audio/audiooutputwin.cpp

@@ -91,14 +91,12 @@ class AudioOutputWinPrivate
     HANDLE    m_hEvent {nullptr};
 };
 
-void CALLBACK AudioOutputWinPrivate::waveOutProc(HWAVEOUT hwo, UINT uMsg,
+void CALLBACK AudioOutputWinPrivate::waveOutProc([[maybe_unused]] HWAVEOUT hwo,
+                                                 UINT uMsg,
                                                  DWORD dwInstance,
-                                                 DWORD dwParam1, DWORD dwParam2)
+                                                 [[maybe_unused]] DWORD dwParam1,
+                                                 [[maybe_unused]] DWORD dwParam2)
 {
-    Q_UNUSED(hwo);
-    Q_UNUSED(dwParam1);
-    Q_UNUSED(dwParam2);
-
     if (uMsg != WOM_DONE)
         return;
 

mythtv/libs/libmythbase/bonjourregister.cpp

@@ -93,14 +93,12 @@ void BonjourRegister::socketReadyRead()
 }
 
 
-void BonjourRegister::BonjourCallback(DNSServiceRef ref, DNSServiceFlags flags,
+void BonjourRegister::BonjourCallback([[maybe_unused]] DNSServiceRef ref,
+                                      [[maybe_unused]] DNSServiceFlags flags,
                                       DNSServiceErrorType errorcode,
                                       const char *name, const char *type,
                                       const char *domain, void *object)
 {
-    (void)ref;
-    (void)flags;
-
     auto *bonjour = static_cast<BonjourRegister *>(object);
     if (bonjour)
     {

mythtv/libs/libmythbase/dbutil.cpp

@@ -187,12 +187,12 @@ bool DBUtil::IsBackupInProgress(void)
  *  \param disableRotation Disable backup rotation
  *  \return                MythDBBackupStatus indicating the result
  */
-MythDBBackupStatus DBUtil::BackupDB(QString &filename, bool disableRotation)
+MythDBBackupStatus DBUtil::BackupDB(QString &filename,
+                                    [[maybe_unused]] bool disableRotation)
 {
     filename = QString();
 
 #ifdef _WIN32
-    Q_UNUSED(disableRotation);
     LOG(VB_GENERAL, LOG_CRIT, "Database backups disabled on Windows.");
     return kDB_Backup_Disabled;
 #else

mythtv/libs/libmythbase/http/mythhttpserver.cpp

@@ -189,7 +189,8 @@ void MythHTTPServer::Init()
     m_config.m_timeout = static_cast<std::chrono::milliseconds>(timeout * 1000);
 }
 
-void MythHTTPServer::Started(bool Tcp, bool Ssl)
+void MythHTTPServer::Started([[maybe_unused]] bool Tcp,
+                             [[maybe_unused]] bool Ssl)
 {
 #ifdef USING_LIBDNS_SD
     // Advertise our webserver
@@ -217,9 +218,6 @@ void MythHTTPServer::Started(bool Tcp, bool Ssl)
         m_bonjourSSL->Register(m_config.m_sslPort, QByteArrayLiteral("_https._tcp"),
             QStringLiteral("%1 on %2").arg(QCoreApplication::applicationName(), host).toLatin1().constData(), {});
     }
-#else
-    Q_UNUSED(Tcp);
-    Q_UNUSED(Ssl);
 #endif
 
     // Build our list of hosts and allowed origins.

mythtv/libs/libmythbase/logging.cpp

@@ -178,8 +178,7 @@ void LoggingItem::setThreadTid(void)
         m_tid = syscall(SYS_gettid);
 #elif defined(__FreeBSD__)
         long lwpid;
-        int dummy = thr_self( &lwpid );
-        (void)dummy;
+        [[maybe_unused]] int dummy = thr_self( &lwpid );
         m_tid = (int64_t)lwpid;
 #elif defined(Q_OS_DARWIN)
         m_tid = (int64_t)mach_thread_self();
@@ -719,17 +718,15 @@ void loggingDeregisterThread(void)
 /// \brief  Map a syslog facility name back to the enumerated value
 /// \param  facility    QString containing the facility name
 /// \return Syslog facility as enumerated type.  Negative if not found.
-int syslogGetFacility(const QString& facility)
+int syslogGetFacility([[maybe_unused]] const QString& facility)
 {
 #ifdef _WIN32
     LOG(VB_GENERAL, LOG_NOTICE,
         "Windows does not support syslog, disabling" );
-    Q_UNUSED(facility);
     return( -2 );
 #elif defined(Q_OS_ANDROID)
     LOG(VB_GENERAL, LOG_NOTICE,
         "Android does not support syslog, disabling" );
-    Q_UNUSED(facility);
     return( -2 );
 #else
     const CODE *name = nullptr;

mythtv/libs/libmythbase/mythcdrom.cpp

@@ -172,9 +172,10 @@ static uint32_t def_size(udfread_block_input *p_gen)
     return (uint32_t)(p->m_file->GetRealFileSize() / UDF_BLOCK_SIZE);
 }
 
-static int def_read(udfread_block_input *p_gen, uint32_t lba, void *buf, uint32_t nblocks, int flags)
+static int def_read(udfread_block_input *p_gen, uint32_t lba,
+                    void *buf, uint32_t nblocks,
+                    [[maybe_unused]] int flags)
 {
-    (void)flags;
     int result = -1;
     auto *p = (blockInput_t *)p_gen;
 

mythtv/libs/libmythbase/mythcorecontext.cpp

@@ -297,7 +297,7 @@ void MythCoreContext::setTestStringSettings(QMap<QString,QString> &overrides)
 
 bool MythCoreContext::SetupCommandSocket(MythSocket *serverSock,
                                          const QString &announcement,
-                                         std::chrono::milliseconds timeout,
+                                         [[maybe_unused]] std::chrono::milliseconds timeout,
                                          bool &proto_mismatch)
 {
     proto_mismatch = false;
@@ -308,8 +308,6 @@ bool MythCoreContext::SetupCommandSocket(MythSocket *serverSock,
         proto_mismatch = true;
         return false;
     }
-#else
-    Q_UNUSED(timeout);
 #endif
 
     QStringList strlist(announcement);
@@ -1652,10 +1650,8 @@ void MythCoreContext::readyRead(MythSocket *sock)
     while (sock->IsDataAvailable());
 }
 
-void MythCoreContext::connectionClosed(MythSocket *sock)
+void MythCoreContext::connectionClosed([[maybe_unused]] MythSocket *sock)
 {
-    (void)sock;
-
     LOG(VB_GENERAL, LOG_NOTICE, LOC +
         "Event socket closed.  No connection to the backend.");
 

mythtv/libs/libmythbase/mythdb.cpp

@@ -57,7 +57,7 @@ void DestroyMythDB(void)
     MythDB::destroyMythDB();
 }
 
-MythDB *GetMythTestDB(const QString& testname)
+MythDB *GetMythTestDB([[maybe_unused]] const QString& testname)
 {
     auto * db = MythDB::getMythDB();
 
@@ -71,7 +71,6 @@ MythDB *GetMythTestDB(const QString& testname)
         QString("mythtv_%1.%2.sqlite3")
         .arg(testname).arg(MythRandom(),8,16,QLatin1Char('0'));
 #else
-    Q_UNUSED(testname);
     params.m_dbName = ":memory:";
 #endif
     params.m_dbType = "QSQLITE";

mythtv/libs/libmythbase/mythmedia.cpp

@@ -304,10 +304,8 @@ void MythMediaDevice::RegisterMediaExtensions(uint mediatype,
         s_ext_to_media[ext] |= mediatype;
 }
 
-MythMediaError MythMediaDevice::eject(bool open_close)
+MythMediaError MythMediaDevice::eject([[maybe_unused]] bool open_close)
 {
-    (void) open_close;
-
 #ifdef Q_OS_DARWIN
     QString  command = "diskutil eject " + m_devicePath;
 

mythtv/libs/libmythbase/mythmiscutil.cpp

@@ -106,7 +106,10 @@ bool getUptime(std::chrono::seconds &uptime)
  *  \todo Memory Statistics are not supported (by MythTV) on NT or DOS.
  *  \return true if it succeeds, false otherwise.
  */
-bool getMemStats(int &totalMB, int &freeMB, int &totalVM, int &freeVM)
+bool getMemStats([[maybe_unused]] int &totalMB,
+                 [[maybe_unused]] int &freeMB,
+                 [[maybe_unused]] int &totalVM,
+                 [[maybe_unused]] int &freeVM)
 {
 #ifdef __linux__
     static constexpr size_t MB { 1024LL * 1024 };
@@ -159,10 +162,6 @@ bool getMemStats(int &totalMB, int &freeMB, int &totalVM, int &freeVM)
     freeVM = (int)(free >> 10);
     return true;
 #else
-    Q_UNUSED(totalMB);
-    Q_UNUSED(freeMB);
-    Q_UNUSED(totalVM);
-    Q_UNUSED(freeVM);
     return false;
 #endif
 }