diff --git a/taglib/ape/apefile.cpp b/taglib/ape/apefile.cpp
index 4d797d1e..c0c9724b 100644
--- a/taglib/ape/apefile.cpp
+++ b/taglib/ape/apefile.cpp
@@ -58,10 +58,10 @@ public:
     APELocation(-1),
     APESize(0),
     ID3v1Location(-1),
-    ID3v2Header(0),
+    ID3v2Header(nullptr),
     ID3v2Location(-1),
     ID3v2Size(0),
-    properties(0) {}
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
@@ -233,10 +233,10 @@ APE::Tag *APE::File::APETag(bool create)
 void APE::File::strip(int tags)
 {
   if(tags & ID3v1)
-    d->tag.set(ApeID3v1Index, 0);
+    d->tag.set(ApeID3v1Index, nullptr);
 
   if(tags & APE)
-    d->tag.set(ApeAPEIndex, 0);
+    d->tag.set(ApeAPEIndex, nullptr);
 
   if(!ID3v1Tag())
     APETag(true);
diff --git a/taglib/ape/apetag.cpp b/taglib/ape/apetag.cpp
index 3cf91b2e..51201015 100644
--- a/taglib/ape/apetag.cpp
+++ b/taglib/ape/apetag.cpp
@@ -52,7 +52,7 @@ namespace
 
   bool isKeyValid(const ByteVector &key)
   {
-    const char *invalidKeys[] = { "ID3", "TAG", "OGGS", "MP+", 0 };
+    const char *invalidKeys[] = { "ID3", "TAG", "OGGS", "MP+", nullptr };
 
     // only allow printable ASCII including space (32..126)
 
@@ -63,7 +63,7 @@ namespace
     }
 
     const String upperKey = String(key).upper();
-    for(size_t i = 0; invalidKeys[i] != 0; ++i) {
+    for(size_t i = 0; invalidKeys[i] != nullptr; ++i) {
       if(upperKey == invalidKeys[i])
         return false;
     }
@@ -76,7 +76,7 @@ class APE::Tag::TagPrivate
 {
 public:
   TagPrivate() :
-    file(0),
+    file(nullptr),
     footerLocation(0) {}
 
   File *file;
diff --git a/taglib/asf/asffile.cpp b/taglib/asf/asffile.cpp
index 921f6f48..ef11041a 100644
--- a/taglib/asf/asffile.cpp
+++ b/taglib/asf/asffile.cpp
@@ -52,13 +52,13 @@ public:
 
   FilePrivate():
     headerSize(0),
-    tag(0),
-    properties(0),
-    contentDescriptionObject(0),
-    extendedContentDescriptionObject(0),
-    headerExtensionObject(0),
-    metadataObject(0),
-    metadataLibraryObject(0)
+    tag(nullptr),
+    properties(nullptr),
+    contentDescriptionObject(nullptr),
+    extendedContentDescriptionObject(nullptr),
+    headerExtensionObject(nullptr),
+    metadataObject(nullptr),
+    metadataLibraryObject(nullptr)
   {
     objects.setAutoDelete(true);
   }
@@ -648,8 +648,8 @@ void ASF::File::read()
   }
   seek(2, Current);
 
-  FilePrivate::FilePropertiesObject   *filePropertiesObject   = 0;
-  FilePrivate::StreamPropertiesObject *streamPropertiesObject = 0;
+  FilePrivate::FilePropertiesObject   *filePropertiesObject   = nullptr;
+  FilePrivate::StreamPropertiesObject *streamPropertiesObject = nullptr;
   for(int i = 0; i < numObjects; i++) {
     const ByteVector guid = readBlock(16);
     if(guid.size() != 16) {
diff --git a/taglib/asf/asfutils.h b/taglib/asf/asfutils.h
index acadaa1e..501c39e3 100644
--- a/taglib/asf/asfutils.h
+++ b/taglib/asf/asfutils.h
@@ -37,7 +37,7 @@ namespace TagLib
     namespace
     {
 
-      inline unsigned short readWORD(File *file, bool *ok = 0)
+      inline unsigned short readWORD(File *file, bool *ok = nullptr)
       {
         const ByteVector v = file->readBlock(2);
         if(v.size() != 2) {
@@ -48,7 +48,7 @@ namespace TagLib
         return v.toUShort(false);
       }
 
-      inline unsigned int readDWORD(File *file, bool *ok = 0)
+      inline unsigned int readDWORD(File *file, bool *ok = nullptr)
       {
         const ByteVector v = file->readBlock(4);
         if(v.size() != 4) {
@@ -59,7 +59,7 @@ namespace TagLib
         return v.toUInt(false);
       }
 
-      inline long long readQWORD(File *file, bool *ok = 0)
+      inline long long readQWORD(File *file, bool *ok = nullptr)
       {
         const ByteVector v = file->readBlock(8);
         if(v.size() != 8) {
diff --git a/taglib/audioproperties.cpp b/taglib/audioproperties.cpp
index a47a5d1e..ca433fd9 100644
--- a/taglib/audioproperties.cpp
+++ b/taglib/audioproperties.cpp
@@ -71,7 +71,7 @@ int AudioProperties::sampleRate() const
 ////////////////////////////////////////////////////////////////////////////////
 
 AudioProperties::AudioProperties(ReadStyle) :
-  d(0)
+  d(nullptr)
 {
 
 }
diff --git a/taglib/fileref.cpp b/taglib/fileref.cpp
index cf08b5b6..6e8f9e31 100644
--- a/taglib/fileref.cpp
+++ b/taglib/fileref.cpp
@@ -72,7 +72,7 @@ namespace
       return 0;
 #else
     if(::strlen(fileName) == 0)
-      return 0;
+      return nullptr;
 #endif
     ResolverList::ConstIterator it = fileTypeResolvers.begin();
     for(; it != fileTypeResolvers.end(); ++it) {
@@ -81,7 +81,7 @@ namespace
         return file;
     }
 
-    return 0;
+    return nullptr;
   }
 
   File *detectByResolvers(IOStream* stream, bool readAudioProperties,
@@ -97,7 +97,7 @@ namespace
       }
     }
 
-    return 0;
+    return nullptr;
   }
 
   // Detect the file type based on the file extension.
@@ -121,11 +121,11 @@ namespace
     // that a default file type resolver is created.
 
     if(ext.isEmpty())
-      return 0;
+      return nullptr;
 
     // .oga can be any audio in the Ogg container. So leave it to content-based detection.
 
-    File *file = 0;
+    File *file = nullptr;
 
     if(ext == "MP3")
       file = new MPEG::File(stream, ID3v2::FrameFactory::instance(), readAudioProperties, audioPropertiesStyle);
@@ -171,7 +171,7 @@ namespace
       delete file;
     }
 
-    return 0;
+    return nullptr;
   }
 
   // Detect the file type based on the actual content of the stream.
@@ -179,7 +179,7 @@ namespace
   File *detectByContent(IOStream *stream, bool readAudioProperties,
                         AudioProperties::ReadStyle audioPropertiesStyle)
   {
-    File *file = 0;
+    File *file = nullptr;
 
     if(MPEG::File::isSupported(stream))
       file = new MPEG::File(stream, ID3v2::FrameFactory::instance(), readAudioProperties, audioPropertiesStyle);
@@ -218,7 +218,7 @@ namespace
       delete file;
     }
 
-    return 0;
+    return nullptr;
   }
 
   // Internal function that supports FileRef::create().
@@ -244,7 +244,7 @@ namespace
       ext = s.substr(pos + 1).upper();
 
     if(ext.isEmpty())
-      return 0;
+      return nullptr;
 
     if(ext == "MP3")
       return new MPEG::File(fileName, ID3v2::FrameFactory::instance(), readAudioProperties, audioPropertiesStyle);
@@ -290,7 +290,7 @@ namespace
     if(ext == "XM")
       return new XM::File(fileName, readAudioProperties, audioPropertiesStyle);
 
-    return 0;
+    return nullptr;
   }
 }  // namespace
 
@@ -298,8 +298,8 @@ class FileRef::FileRefPrivate : public RefCounter
 {
 public:
   FileRefPrivate() :
-    file(0),
-    stream(0) {}
+    file(nullptr),
+    stream(nullptr) {}
 
   ~FileRefPrivate() override {
     delete file;
@@ -354,7 +354,7 @@ Tag *FileRef::tag() const
 {
   if(isNull()) {
     debug("FileRef::tag() - Called without a valid file.");
-    return 0;
+    return nullptr;
   }
   return d->file->tag();
 }
@@ -363,7 +363,7 @@ AudioProperties *FileRef::audioProperties() const
 {
   if(isNull()) {
     debug("FileRef::audioProperties() - Called without a valid file.");
-    return 0;
+    return nullptr;
   }
   return d->file->audioProperties();
 }
@@ -490,7 +490,7 @@ void FileRef::parse(FileName fileName, bool readAudioProperties,
   // Stream have to be closed here if failed to resolve file types.
 
   delete d->stream;
-  d->stream = 0;
+  d->stream = nullptr;
 }
 
 void FileRef::parse(IOStream *stream, bool readAudioProperties,
diff --git a/taglib/flac/flacfile.cpp b/taglib/flac/flacfile.cpp
index b2599227..bde1cd1b 100644
--- a/taglib/flac/flacfile.cpp
+++ b/taglib/flac/flacfile.cpp
@@ -65,7 +65,7 @@ public:
     ID3v2Location(-1),
     ID3v2OriginalSize(0),
     ID3v1Location(-1),
-    properties(0),
+    properties(nullptr),
     flacStart(0),
     streamStart(0),
     scanned(false)
@@ -199,7 +199,7 @@ bool FLAC::File::save()
     if(commentBlock && (*it)->code() == MetadataBlock::Picture) {
       // Set the new Vorbis Comment block before the first picture block
       d->blocks.insert(it, commentBlock);
-      commentBlock = 0;
+      commentBlock = nullptr;
     }
     ++it;
   }
@@ -373,10 +373,10 @@ void FLAC::File::removePictures()
 void FLAC::File::strip(int tags)
 {
   if(tags & ID3v1)
-    d->tag.set(FlacID3v1Index, 0);
+    d->tag.set(FlacID3v1Index, nullptr);
 
   if(tags & ID3v2)
-    d->tag.set(FlacID3v2Index, 0);
+    d->tag.set(FlacID3v2Index, nullptr);
 
   if(tags & XiphComment) {
     xiphComment()->removeAllFields();
@@ -525,7 +525,7 @@ void FLAC::File::scan()
       return;
     }
 
-    MetadataBlock *block = 0;
+    MetadataBlock *block = nullptr;
 
     // Found the vorbis-comment
     if(blockType == MetadataBlock::VorbisComment) {
diff --git a/taglib/flac/flacmetadatablock.cpp b/taglib/flac/flacmetadatablock.cpp
index 8b795f22..695e559b 100644
--- a/taglib/flac/flacmetadatablock.cpp
+++ b/taglib/flac/flacmetadatablock.cpp
@@ -37,7 +37,7 @@ public:
 };
 
 FLAC::MetadataBlock::MetadataBlock()
-  : d(0)
+  : d(nullptr)
 {
 }
 
diff --git a/taglib/mp4/mp4atom.cpp b/taglib/mp4/mp4atom.cpp
index edd615f2..2d57deb6 100644
--- a/taglib/mp4/mp4atom.cpp
+++ b/taglib/mp4/mp4atom.cpp
@@ -136,7 +136,7 @@ MP4::Atom::~Atom()
 MP4::Atom *
 MP4::Atom::find(const char *name1, const char *name2, const char *name3, const char *name4)
 {
-  if(name1 == 0) {
+  if(name1 == nullptr) {
     return this;
   }
   for(AtomList::ConstIterator it = children.begin(); it != children.end(); ++it) {
@@ -144,7 +144,7 @@ MP4::Atom::find(const char *name1, const char *name2, const char *name3, const c
       return (*it)->find(name2, name3, name4);
     }
   }
-  return 0;
+  return nullptr;
 }
 
 MP4::AtomList
@@ -166,7 +166,7 @@ bool
 MP4::Atom::path(MP4::AtomList &path, const char *name1, const char *name2, const char *name3)
 {
   path.append(this);
-  if(name1 == 0) {
+  if(name1 == nullptr) {
     return true;
   }
   for(AtomList::ConstIterator it = children.begin(); it != children.end(); ++it) {
@@ -204,7 +204,7 @@ MP4::Atoms::find(const char *name1, const char *name2, const char *name3, const
       return (*it)->find(name2, name3, name4);
     }
   }
-  return 0;
+  return nullptr;
 }
 
 MP4::AtomList
diff --git a/taglib/mp4/mp4atom.h b/taglib/mp4/mp4atom.h
index 48873cc9..1578c0e8 100644
--- a/taglib/mp4/mp4atom.h
+++ b/taglib/mp4/mp4atom.h
@@ -77,8 +77,8 @@ namespace TagLib {
     public:
       Atom(File *file);
       ~Atom();
-      Atom *find(const char *name1, const char *name2 = 0, const char *name3 = 0, const char *name4 = 0);
-      bool path(AtomList &path, const char *name1, const char *name2 = 0, const char *name3 = 0);
+      Atom *find(const char *name1, const char *name2 = nullptr, const char *name3 = nullptr, const char *name4 = nullptr);
+      bool path(AtomList &path, const char *name1, const char *name2 = nullptr, const char *name3 = nullptr);
       AtomList findall(const char *name, bool recursive = false);
       offset_t offset;
       offset_t length;
@@ -95,8 +95,8 @@ namespace TagLib {
     public:
       Atoms(File *file);
       ~Atoms();
-      Atom *find(const char *name1, const char *name2 = 0, const char *name3 = 0, const char *name4 = 0);
-      AtomList path(const char *name1, const char *name2 = 0, const char *name3 = 0, const char *name4 = 0);
+      Atom *find(const char *name1, const char *name2 = nullptr, const char *name3 = nullptr, const char *name4 = nullptr);
+      AtomList path(const char *name1, const char *name2 = nullptr, const char *name3 = nullptr, const char *name4 = nullptr);
       AtomList atoms;
     };
   }  // namespace MP4
diff --git a/taglib/mp4/mp4file.cpp b/taglib/mp4/mp4file.cpp
index 1747d62c..37a9a365 100644
--- a/taglib/mp4/mp4file.cpp
+++ b/taglib/mp4/mp4file.cpp
@@ -55,9 +55,9 @@ class MP4::File::FilePrivate
 {
 public:
   FilePrivate() :
-    tag(0),
-    atoms(0),
-    properties(0) {}
+    tag(nullptr),
+    atoms(nullptr),
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
@@ -198,5 +198,5 @@ MP4::File::strip(int tags)
 bool
 MP4::File::hasMP4Tag() const
 {
-  return (d->atoms->find("moov", "udta", "meta", "ilst") != 0);
+  return (d->atoms->find("moov", "udta", "meta", "ilst") != nullptr);
 }
diff --git a/taglib/mp4/mp4properties.cpp b/taglib/mp4/mp4properties.cpp
index b24cfe24..823987fb 100644
--- a/taglib/mp4/mp4properties.cpp
+++ b/taglib/mp4/mp4properties.cpp
@@ -144,7 +144,7 @@ MP4::Properties::read(File *file, Atoms *atoms)
     return;
   }
 
-  MP4::Atom *trak = 0;
+  MP4::Atom *trak = nullptr;
   ByteVector data;
 
   const MP4::AtomList trakList = moov->findall("trak");
@@ -160,7 +160,7 @@ MP4::Properties::read(File *file, Atoms *atoms)
     if(data.containsAt("soun", 16)) {
       break;
     }
-    trak = 0;
+    trak = nullptr;
   }
   if(!trak) {
     debug("MP4: No audio tracks");
diff --git a/taglib/mp4/mp4tag.cpp b/taglib/mp4/mp4tag.cpp
index cff5c701..590ace97 100644
--- a/taglib/mp4/mp4tag.cpp
+++ b/taglib/mp4/mp4tag.cpp
@@ -36,8 +36,8 @@ class MP4::Tag::TagPrivate
 {
 public:
   TagPrivate() :
-    file(0),
-    atoms(0) {}
+    file(nullptr),
+    atoms(nullptr) {}
 
   TagLib::File *file;
   Atoms *atoms;
diff --git a/taglib/mpc/mpcfile.cpp b/taglib/mpc/mpcfile.cpp
index 28b4c11c..ab067999 100644
--- a/taglib/mpc/mpcfile.cpp
+++ b/taglib/mpc/mpcfile.cpp
@@ -50,10 +50,10 @@ public:
     APELocation(-1),
     APESize(0),
     ID3v1Location(-1),
-    ID3v2Header(0),
+    ID3v2Header(nullptr),
     ID3v2Location(-1),
     ID3v2Size(0),
-    properties(0) {}
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
@@ -241,17 +241,17 @@ APE::Tag *MPC::File::APETag(bool create)
 void MPC::File::strip(int tags)
 {
   if(tags & ID3v1)
-    d->tag.set(MPCID3v1Index, 0);
+    d->tag.set(MPCID3v1Index, nullptr);
 
   if(tags & APE)
-    d->tag.set(MPCAPEIndex, 0);
+    d->tag.set(MPCAPEIndex, nullptr);
 
   if(!ID3v1Tag())
     APETag(true);
 
   if(tags & ID3v2) {
     delete d->ID3v2Header;
-    d->ID3v2Header = 0;
+    d->ID3v2Header = nullptr;
   }
 }
 
diff --git a/taglib/mpeg/id3v1/id3v1tag.cpp b/taglib/mpeg/id3v1/id3v1tag.cpp
index cfec2cb1..cc335bda 100644
--- a/taglib/mpeg/id3v1/id3v1tag.cpp
+++ b/taglib/mpeg/id3v1/id3v1tag.cpp
@@ -42,7 +42,7 @@ class ID3v1::Tag::TagPrivate
 {
 public:
   TagPrivate() :
-    file(0),
+    file(nullptr),
     tagOffset(0),
     track(0),
     genre(255) {}
diff --git a/taglib/mpeg/id3v2/frames/chapterframe.cpp b/taglib/mpeg/id3v2/frames/chapterframe.cpp
index 540c87b5..0794cdf9 100644
--- a/taglib/mpeg/id3v2/frames/chapterframe.cpp
+++ b/taglib/mpeg/id3v2/frames/chapterframe.cpp
@@ -37,7 +37,7 @@ class ChapterFrame::ChapterFramePrivate
 {
 public:
   ChapterFramePrivate() :
-    tagHeader(0),
+    tagHeader(nullptr),
     startTime(0),
     endTime(0),
     startOffset(0),
@@ -236,7 +236,7 @@ ChapterFrame *ChapterFrame::findByElementID(const ID3v2::Tag *tag, const ByteVec
       return frame;
   }
 
-  return 0;
+  return nullptr;
 }
 
 void ChapterFrame::parseFields(const ByteVector &data)
diff --git a/taglib/mpeg/id3v2/frames/commentsframe.cpp b/taglib/mpeg/id3v2/frames/commentsframe.cpp
index add0bf2f..07fa1502 100644
--- a/taglib/mpeg/id3v2/frames/commentsframe.cpp
+++ b/taglib/mpeg/id3v2/frames/commentsframe.cpp
@@ -136,7 +136,7 @@ CommentsFrame *CommentsFrame::findByDescription(const ID3v2::Tag *tag, const Str
       return frame;
   }
 
-  return 0;
+  return nullptr;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/taglib/mpeg/id3v2/frames/tableofcontentsframe.cpp b/taglib/mpeg/id3v2/frames/tableofcontentsframe.cpp
index 9061a9bc..3f16acbe 100644
--- a/taglib/mpeg/id3v2/frames/tableofcontentsframe.cpp
+++ b/taglib/mpeg/id3v2/frames/tableofcontentsframe.cpp
@@ -36,7 +36,7 @@ class TableOfContentsFrame::TableOfContentsFramePrivate
 {
 public:
   TableOfContentsFramePrivate() :
-    tagHeader(0),
+    tagHeader(nullptr),
     isTopLevel(false),
     isOrdered(false)
   {
@@ -262,7 +262,7 @@ TableOfContentsFrame *TableOfContentsFrame::findByElementID(const ID3v2::Tag *ta
       return frame;
   }
 
-  return 0;
+  return nullptr;
 }
 
 TableOfContentsFrame *TableOfContentsFrame::findTopLevel(const ID3v2::Tag *tag) // static
@@ -278,7 +278,7 @@ TableOfContentsFrame *TableOfContentsFrame::findTopLevel(const ID3v2::Tag *tag)
       return frame;
   }
 
-  return 0;
+  return nullptr;
 }
 
 void TableOfContentsFrame::parseFields(const ByteVector &data)
diff --git a/taglib/mpeg/id3v2/frames/textidentificationframe.cpp b/taglib/mpeg/id3v2/frames/textidentificationframe.cpp
index cda40d95..35b10703 100644
--- a/taglib/mpeg/id3v2/frames/textidentificationframe.cpp
+++ b/taglib/mpeg/id3v2/frames/textidentificationframe.cpp
@@ -337,7 +337,7 @@ PropertyMap TextIdentificationFrame::makeTMCLProperties() const
 
 UserTextIdentificationFrame::UserTextIdentificationFrame(String::Type encoding) :
   TextIdentificationFrame("TXXX", encoding),
-  d(0)
+  d(nullptr)
 {
   StringList l;
   l.append(String());
@@ -354,7 +354,7 @@ UserTextIdentificationFrame::UserTextIdentificationFrame(const ByteVector &data)
 
 UserTextIdentificationFrame::UserTextIdentificationFrame(const String &description, const StringList &values, String::Type encoding) :
     TextIdentificationFrame("TXXX", encoding),
-    d(0)
+    d(nullptr)
 {
   setDescription(description);
   setText(values);
@@ -433,7 +433,7 @@ UserTextIdentificationFrame *UserTextIdentificationFrame::find(
     if(f && f->description() == description)
       return f;
   }
-  return 0;
+  return nullptr;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/taglib/mpeg/id3v2/frames/uniquefileidentifierframe.cpp b/taglib/mpeg/id3v2/frames/uniquefileidentifierframe.cpp
index dd26482a..98fa7546 100644
--- a/taglib/mpeg/id3v2/frames/uniquefileidentifierframe.cpp
+++ b/taglib/mpeg/id3v2/frames/uniquefileidentifierframe.cpp
@@ -114,7 +114,7 @@ UniqueFileIdentifierFrame *UniqueFileIdentifierFrame::findByOwner(const ID3v2::T
       return frame;
   }
 
-  return 0;
+  return nullptr;
 }
 
 void UniqueFileIdentifierFrame::parseFields(const ByteVector &data)
diff --git a/taglib/mpeg/id3v2/frames/unsynchronizedlyricsframe.cpp b/taglib/mpeg/id3v2/frames/unsynchronizedlyricsframe.cpp
index db089dbf..e6afbc40 100644
--- a/taglib/mpeg/id3v2/frames/unsynchronizedlyricsframe.cpp
+++ b/taglib/mpeg/id3v2/frames/unsynchronizedlyricsframe.cpp
@@ -134,7 +134,7 @@ UnsynchronizedLyricsFrame *UnsynchronizedLyricsFrame::findByDescription(const ID
     if(frame && frame->description() == d)
       return frame;
   }
-  return 0;
+  return nullptr;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // protected members
diff --git a/taglib/mpeg/id3v2/frames/urllinkframe.cpp b/taglib/mpeg/id3v2/frames/urllinkframe.cpp
index 9e7982d4..2f32e5c8 100644
--- a/taglib/mpeg/id3v2/frames/urllinkframe.cpp
+++ b/taglib/mpeg/id3v2/frames/urllinkframe.cpp
@@ -185,7 +185,7 @@ UserUrlLinkFrame *UserUrlLinkFrame::find(ID3v2::Tag *tag, const String &descript
     if(f && f->description() == description)
       return f;
   }
-  return 0;
+  return nullptr;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/taglib/mpeg/id3v2/id3v2footer.cpp b/taglib/mpeg/id3v2/id3v2footer.cpp
index 3622724a..2d1ec7d0 100644
--- a/taglib/mpeg/id3v2/id3v2footer.cpp
+++ b/taglib/mpeg/id3v2/id3v2footer.cpp
@@ -34,7 +34,7 @@ class Footer::FooterPrivate
 };
 
 Footer::Footer() :
-  d(0)
+  d(nullptr)
 {
 }
 
diff --git a/taglib/mpeg/id3v2/id3v2frame.cpp b/taglib/mpeg/id3v2/id3v2frame.cpp
index 9e3ac82a..b57ce928 100644
--- a/taglib/mpeg/id3v2/id3v2frame.cpp
+++ b/taglib/mpeg/id3v2/id3v2frame.cpp
@@ -49,7 +49,7 @@ class Frame::FramePrivate
 {
 public:
   FramePrivate() :
-    header(0)
+    header(nullptr)
     {}
 
   ~FramePrivate()
diff --git a/taglib/mpeg/id3v2/id3v2frame.h b/taglib/mpeg/id3v2/id3v2frame.h
index c2db6593..044ac4f8 100644
--- a/taglib/mpeg/id3v2/id3v2frame.h
+++ b/taglib/mpeg/id3v2/id3v2frame.h
@@ -214,7 +214,7 @@ namespace TagLib {
        * This is useful for reading strings sequentially.
        */
       String readStringField(const ByteVector &data, String::Type encoding,
-                             int *position = 0);
+                             int *position = nullptr);
 
       /*!
        * Checks a the list of string values to see if they can be used with the
diff --git a/taglib/mpeg/id3v2/id3v2framefactory.cpp b/taglib/mpeg/id3v2/id3v2framefactory.cpp
index 730784d0..4377dad4 100644
--- a/taglib/mpeg/id3v2/id3v2framefactory.cpp
+++ b/taglib/mpeg/id3v2/id3v2framefactory.cpp
@@ -130,7 +130,7 @@ Frame *FrameFactory::createFrame(const ByteVector &origData, const Header *tagHe
      header->frameSize() > data.size())
   {
     delete header;
-    return 0;
+    return nullptr;
   }
 
 #ifndef NO_ITUNES_HACKS
@@ -147,7 +147,7 @@ Frame *FrameFactory::createFrame(const ByteVector &origData, const Header *tagHe
   for(ByteVector::ConstIterator it = frameID.begin(); it != frameID.end(); it++) {
     if( (*it < 'A' || *it > 'Z') && (*it < '0' || *it > '9') ) {
       delete header;
-      return 0;
+      return nullptr;
     }
   }
 
diff --git a/taglib/mpeg/id3v2/id3v2tag.cpp b/taglib/mpeg/id3v2/id3v2tag.cpp
index 66e35119..a7be802a 100644
--- a/taglib/mpeg/id3v2/id3v2tag.cpp
+++ b/taglib/mpeg/id3v2/id3v2tag.cpp
@@ -70,11 +70,11 @@ class ID3v2::Tag::TagPrivate
 {
 public:
   TagPrivate() :
-    factory(0),
-    file(0),
+    factory(nullptr),
+    file(nullptr),
     tagOffset(0),
-    extendedHeader(0),
-    footer(0)
+    extendedHeader(nullptr),
+    footer(nullptr)
   {
     frameList.setAutoDelete(true);
   }
@@ -404,7 +404,7 @@ void ID3v2::Tag::removeUnsupportedProperties(const StringList &properties)
       // delete all unknown frames of given type
       FrameList l = frameList(id);
       for(FrameList::ConstIterator fit = l.begin(); fit != l.end(); fit++)
-        if (dynamic_cast<const UnknownFrame *>(*fit) != 0)
+        if (dynamic_cast<const UnknownFrame *>(*fit) != nullptr)
           removeFrame(*fit);
     }
     else if(it->size() == 4){
@@ -416,7 +416,7 @@ void ID3v2::Tag::removeUnsupportedProperties(const StringList &properties)
       if(it->size() <= 5)
         continue; // invalid specification
       String description = it->substr(5);
-      Frame *frame = 0;
+      Frame *frame = nullptr;
       if(id == "TXXX")
         frame = UserTextIdentificationFrame::find(this, description);
       else if(id == "WXXX")
@@ -493,14 +493,14 @@ void ID3v2::Tag::downgradeFrames(FrameList *frames, FrameList *newFrames) const
   // iTunes writes and reads TSOA, TSOT, TSOP to ID3v2.3.
   static const char *unsupportedFrames[] = {
     "ASPI", "EQU2", "RVA2", "SEEK", "SIGN", "TDRL", "TDTG",
-    "TMOO", "TPRO", "TSST", 0
+    "TMOO", "TPRO", "TSST", nullptr
   };
 #endif
-  ID3v2::TextIdentificationFrame *frameTDOR = 0;
-  ID3v2::TextIdentificationFrame *frameTDRC = 0;
-  ID3v2::TextIdentificationFrame *frameTIPL = 0;
-  ID3v2::TextIdentificationFrame *frameTMCL = 0;
-  ID3v2::TextIdentificationFrame *frameTCON = 0;
+  ID3v2::TextIdentificationFrame *frameTDOR = nullptr;
+  ID3v2::TextIdentificationFrame *frameTDRC = nullptr;
+  ID3v2::TextIdentificationFrame *frameTIPL = nullptr;
+  ID3v2::TextIdentificationFrame *frameTMCL = nullptr;
+  ID3v2::TextIdentificationFrame *frameTCON = nullptr;
 
   for(FrameList::ConstIterator it = d->frameList.begin(); it != d->frameList.end(); it++) {
     ID3v2::Frame *frame = *it;
diff --git a/taglib/mpeg/mpegfile.cpp b/taglib/mpeg/mpegfile.cpp
index 91295776..3d3d4b29 100644
--- a/taglib/mpeg/mpegfile.cpp
+++ b/taglib/mpeg/mpegfile.cpp
@@ -54,7 +54,7 @@ public:
     APELocation(-1),
     APEOriginalSize(0),
     ID3v1Location(-1),
-    properties(0) {}
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
@@ -89,8 +89,8 @@ namespace
   public:
     AdapterFile(IOStream *stream) : File(stream) {}
 
-    Tag *tag() const override { return 0; }
-    AudioProperties *audioProperties() const override { return 0; }
+    Tag *tag() const override { return nullptr; }
+    AudioProperties *audioProperties() const override { return nullptr; }
     bool save() override { return false; }
   };
 }  // namespace
@@ -343,7 +343,7 @@ bool MPEG::File::strip(int tags, bool freeMemory)
     d->ID3v2OriginalSize = 0;
 
     if(freeMemory)
-      d->tag.set(ID3v2Index, 0);
+      d->tag.set(ID3v2Index, nullptr);
   }
 
   if((tags & ID3v1) && d->ID3v1Location >= 0) {
@@ -352,7 +352,7 @@ bool MPEG::File::strip(int tags, bool freeMemory)
     d->ID3v1Location = -1;
 
     if(freeMemory)
-      d->tag.set(ID3v1Index, 0);
+      d->tag.set(ID3v1Index, nullptr);
   }
 
   if((tags & APE) && d->APELocation >= 0) {
@@ -365,7 +365,7 @@ bool MPEG::File::strip(int tags, bool freeMemory)
     d->APEOriginalSize = 0;
 
     if(freeMemory)
-      d->tag.set(APEIndex, 0);
+      d->tag.set(APEIndex, nullptr);
   }
 
   return true;
diff --git a/taglib/mpeg/mpegproperties.cpp b/taglib/mpeg/mpegproperties.cpp
index babad890..8d586c70 100644
--- a/taglib/mpeg/mpegproperties.cpp
+++ b/taglib/mpeg/mpegproperties.cpp
@@ -38,7 +38,7 @@ class MPEG::Properties::PropertiesPrivate
 {
 public:
   PropertiesPrivate() :
-    xingHeader(0),
+    xingHeader(nullptr),
     length(0),
     bitrate(0),
     sampleRate(0),
@@ -162,7 +162,7 @@ void MPEG::Properties::read(File *file)
   d->xingHeader = new XingHeader(file->readBlock(firstHeader.frameLength()));
   if(!d->xingHeader->isValid()) {
     delete d->xingHeader;
-    d->xingHeader = 0;
+    d->xingHeader = nullptr;
   }
 
   if(d->xingHeader && firstHeader.samplesPerFrame() > 0 && firstHeader.sampleRate() > 0) {
diff --git a/taglib/ogg/flac/oggflacfile.cpp b/taglib/ogg/flac/oggflacfile.cpp
index 5c2f95c6..b6527e96 100644
--- a/taglib/ogg/flac/oggflacfile.cpp
+++ b/taglib/ogg/flac/oggflacfile.cpp
@@ -39,8 +39,8 @@ class Ogg::FLAC::File::FilePrivate
 {
 public:
   FilePrivate() :
-    comment(0),
-    properties(0),
+    comment(nullptr),
+    properties(nullptr),
     streamStart(0),
     streamLength(0),
     scanned(false),
diff --git a/taglib/ogg/oggfile.cpp b/taglib/ogg/oggfile.cpp
index 86063915..9ffed806 100644
--- a/taglib/ogg/oggfile.cpp
+++ b/taglib/ogg/oggfile.cpp
@@ -49,8 +49,8 @@ class Ogg::File::FilePrivate
 {
 public:
   FilePrivate() :
-    firstPageHeader(0),
-    lastPageHeader(0)
+    firstPageHeader(nullptr),
+    lastPageHeader(nullptr)
   {
     pages.setAutoDelete(true);
   }
@@ -131,12 +131,12 @@ const Ogg::PageHeader *Ogg::File::firstPageHeader()
   if(!d->firstPageHeader) {
     const offset_t firstPageHeaderOffset = find("OggS");
     if(firstPageHeaderOffset < 0)
-      return 0;
+      return nullptr;
 
     d->firstPageHeader = new PageHeader(this, firstPageHeaderOffset);
   }
 
-  return d->firstPageHeader->isValid() ? d->firstPageHeader : 0;
+  return d->firstPageHeader->isValid() ? d->firstPageHeader : nullptr;
 }
 
 const Ogg::PageHeader *Ogg::File::lastPageHeader()
@@ -144,12 +144,12 @@ const Ogg::PageHeader *Ogg::File::lastPageHeader()
   if(!d->lastPageHeader) {
     const offset_t lastPageHeaderOffset = rfind("OggS");
     if(lastPageHeaderOffset < 0)
-      return 0;
+      return nullptr;
 
     d->lastPageHeader = new PageHeader(this, lastPageHeaderOffset);
   }
 
-  return d->lastPageHeader->isValid() ? d->lastPageHeader : 0;
+  return d->lastPageHeader->isValid() ? d->lastPageHeader : nullptr;
 }
 
 bool Ogg::File::save()
diff --git a/taglib/ogg/oggpage.cpp b/taglib/ogg/oggpage.cpp
index affb55a3..7fcaf4ad 100644
--- a/taglib/ogg/oggpage.cpp
+++ b/taglib/ogg/oggpage.cpp
@@ -100,7 +100,7 @@ unsigned int pageChecksum(const ByteVector &data)
 class Ogg::Page::PagePrivate
 {
 public:
-  PagePrivate(File *f = 0, offset_t pageOffset = -1) :
+  PagePrivate(File *f = nullptr, offset_t pageOffset = -1) :
     file(f),
     fileOffset(pageOffset),
     header(f, pageOffset),
diff --git a/taglib/ogg/oggpageheader.h b/taglib/ogg/oggpageheader.h
index 29709626..91af3e75 100644
--- a/taglib/ogg/oggpageheader.h
+++ b/taglib/ogg/oggpageheader.h
@@ -52,7 +52,7 @@ namespace TagLib {
        * create a page with no (and as such, invalid) data that must be set
        * later.
        */
-      PageHeader(File *file = 0, offset_t pageOffset = -1);
+      PageHeader(File *file = nullptr, offset_t pageOffset = -1);
 
       /*!
        * Deletes this instance of the PageHeader.
diff --git a/taglib/ogg/opus/opusfile.cpp b/taglib/ogg/opus/opusfile.cpp
index d4f191ad..9b181660 100644
--- a/taglib/ogg/opus/opusfile.cpp
+++ b/taglib/ogg/opus/opusfile.cpp
@@ -41,8 +41,8 @@ class Opus::File::FilePrivate
 {
 public:
   FilePrivate() :
-    comment(0),
-    properties(0) {}
+    comment(nullptr),
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
diff --git a/taglib/ogg/speex/speexfile.cpp b/taglib/ogg/speex/speexfile.cpp
index 394cb17b..bb883a31 100644
--- a/taglib/ogg/speex/speexfile.cpp
+++ b/taglib/ogg/speex/speexfile.cpp
@@ -41,8 +41,8 @@ class Speex::File::FilePrivate
 {
 public:
   FilePrivate() :
-    comment(0),
-    properties(0) {}
+    comment(nullptr),
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
diff --git a/taglib/ogg/vorbis/vorbisfile.cpp b/taglib/ogg/vorbis/vorbisfile.cpp
index a7512bec..5b527b85 100644
--- a/taglib/ogg/vorbis/vorbisfile.cpp
+++ b/taglib/ogg/vorbis/vorbisfile.cpp
@@ -38,8 +38,8 @@ class Vorbis::File::FilePrivate
 {
 public:
   FilePrivate() :
-    comment(0),
-    properties(0) {}
+    comment(nullptr),
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
diff --git a/taglib/riff/aiff/aifffile.cpp b/taglib/riff/aiff/aifffile.cpp
index 6ef4c9be..081df55d 100644
--- a/taglib/riff/aiff/aifffile.cpp
+++ b/taglib/riff/aiff/aifffile.cpp
@@ -38,8 +38,8 @@ class RIFF::AIFF::File::FilePrivate
 {
 public:
   FilePrivate() :
-    properties(0),
-    tag(0),
+    properties(nullptr),
+    tag(nullptr),
     hasID3v2(false) {}
 
   ~FilePrivate()
diff --git a/taglib/riff/wav/wavfile.cpp b/taglib/riff/wav/wavfile.cpp
index 8cd84364..e829c5ec 100644
--- a/taglib/riff/wav/wavfile.cpp
+++ b/taglib/riff/wav/wavfile.cpp
@@ -45,7 +45,7 @@ class RIFF::WAV::File::FilePrivate
 {
 public:
   FilePrivate() :
-    properties(0),
+    properties(nullptr),
     hasID3v2(false),
     hasInfo(false) {}
 
diff --git a/taglib/tagunion.cpp b/taglib/tagunion.cpp
index 3a022550..cf42bd7b 100644
--- a/taglib/tagunion.cpp
+++ b/taglib/tagunion.cpp
@@ -64,7 +64,7 @@ using namespace TagLib;
 class TagUnion::TagUnionPrivate
 {
 public:
-  TagUnionPrivate() : tags(3, static_cast<Tag *>(0))
+  TagUnionPrivate() : tags(3, static_cast<Tag *>(nullptr))
   {
 
   }
diff --git a/taglib/tagunion.h b/taglib/tagunion.h
index 78fd2e29..ff9eab3c 100644
--- a/taglib/tagunion.h
+++ b/taglib/tagunion.h
@@ -47,7 +47,7 @@ namespace TagLib {
      * \a third.  The TagUnion takes ownership of these tags and will handle
      * their deletion.
      */
-    TagUnion(Tag *first = 0, Tag *second = 0, Tag *third = 0);
+    TagUnion(Tag *first = nullptr, Tag *second = nullptr, Tag *third = nullptr);
 
     ~TagUnion() override;
 
diff --git a/taglib/tagutils.h b/taglib/tagutils.h
index c2bba562..d21edef3 100644
--- a/taglib/tagutils.h
+++ b/taglib/tagutils.h
@@ -46,7 +46,7 @@ namespace TagLib {
     offset_t findAPE(File *file, offset_t id3v1Location);
 
     ByteVector readHeader(IOStream *stream, unsigned int length, bool skipID3v2,
-                          offset_t *headerOffset = 0);
+                          offset_t *headerOffset = nullptr);
   }  // namespace Utils
 }  // namespace TagLib
 
diff --git a/taglib/toolkit/tbytevector.cpp b/taglib/toolkit/tbytevector.cpp
index 70fc4ec4..529773c0 100644
--- a/taglib/toolkit/tbytevector.cpp
+++ b/taglib/toolkit/tbytevector.cpp
@@ -392,12 +392,12 @@ ByteVector &ByteVector::setData(const char *data)
 char *ByteVector::data()
 {
   detach();
-  return (size() > 0) ? (&(*d->data)[d->offset]) : 0;
+  return (size() > 0) ? (&(*d->data)[d->offset]) : nullptr;
 }
 
 const char *ByteVector::data() const
 {
-  return (size() > 0) ? (&(*d->data)[d->offset]) : 0;
+  return (size() > 0) ? (&(*d->data)[d->offset]) : nullptr;
 }
 
 ByteVector ByteVector::mid(unsigned int index, unsigned int length) const
diff --git a/taglib/toolkit/tfilestream.cpp b/taglib/toolkit/tfilestream.cpp
index 18a1a1d3..3a0397b7 100644
--- a/taglib/toolkit/tfilestream.cpp
+++ b/taglib/toolkit/tfilestream.cpp
@@ -96,7 +96,7 @@ namespace
 
   typedef FILE* FileHandle;
 
-  const FileHandle InvalidFileHandle = 0;
+  const FileHandle InvalidFileHandle = nullptr;
 
   FileHandle openFile(const FileName &path, bool readOnly)
   {
diff --git a/taglib/toolkit/tstring.h b/taglib/toolkit/tstring.h
index 0c8d785a..f9146466 100644
--- a/taglib/toolkit/tstring.h
+++ b/taglib/toolkit/tstring.h
@@ -345,7 +345,7 @@ namespace TagLib {
      * true and returns the integer. Otherwise it sets \a *ok to false
      * and the result is undefined.
      */
-    int toInt(bool *ok = 0) const;
+    int toInt(bool *ok = nullptr) const;
 
     /*!
      * Returns a string with the leading and trailing whitespace stripped.
diff --git a/taglib/trueaudio/trueaudiofile.cpp b/taglib/trueaudio/trueaudiofile.cpp
index 7361122f..4f2975bd 100644
--- a/taglib/trueaudio/trueaudiofile.cpp
+++ b/taglib/trueaudio/trueaudiofile.cpp
@@ -55,7 +55,7 @@ public:
     ID3v2Location(-1),
     ID3v2OriginalSize(0),
     ID3v1Location(-1),
-    properties(0) {}
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
@@ -237,10 +237,10 @@ ID3v2::Tag *TrueAudio::File::ID3v2Tag(bool create)
 void TrueAudio::File::strip(int tags)
 {
   if(tags & ID3v1)
-    d->tag.set(TrueAudioID3v1Index, 0);
+    d->tag.set(TrueAudioID3v1Index, nullptr);
 
   if(tags & ID3v2)
-    d->tag.set(TrueAudioID3v2Index, 0);
+    d->tag.set(TrueAudioID3v2Index, nullptr);
 
   if(!ID3v1Tag())
     ID3v2Tag(true);
diff --git a/taglib/wavpack/wavpackfile.cpp b/taglib/wavpack/wavpackfile.cpp
index bdca24ca..9da4c935 100644
--- a/taglib/wavpack/wavpackfile.cpp
+++ b/taglib/wavpack/wavpackfile.cpp
@@ -54,7 +54,7 @@ public:
     APELocation(-1),
     APESize(0),
     ID3v1Location(-1),
-    properties(0) {}
+    properties(nullptr) {}
 
   ~FilePrivate()
   {
@@ -221,10 +221,10 @@ APE::Tag *WavPack::File::APETag(bool create)
 void WavPack::File::strip(int tags)
 {
   if(tags & ID3v1)
-    d->tag.set(WavID3v1Index, 0);
+    d->tag.set(WavID3v1Index, nullptr);
 
   if(tags & APE)
-    d->tag.set(WavAPEIndex, 0);
+    d->tag.set(WavAPEIndex, nullptr);
 
   if(!ID3v1Tag())
     APETag(true);
diff --git a/tests/plainfile.h b/tests/plainfile.h
index 3250816f..dc808277 100644
--- a/tests/plainfile.h
+++ b/tests/plainfile.h
@@ -34,8 +34,8 @@ using namespace TagLib;
 class PlainFile : public File {
 public:
   explicit PlainFile(FileName name) : File(name) { }
-  Tag *tag() const override { return NULL; }
-  AudioProperties *audioProperties() const override { return NULL; }
+  Tag *tag() const override { return nullptr; }
+  AudioProperties *audioProperties() const override { return nullptr; }
   bool save() override { return false; }
   void truncate(long length) { File::truncate(length); }
 
diff --git a/tests/test_fileref.cpp b/tests/test_fileref.cpp
index 2910803d..dc946fe3 100644
--- a/tests/test_fileref.cpp
+++ b/tests/test_fileref.cpp
@@ -66,7 +66,7 @@ namespace
   public:
     File *createFile(FileName, bool, AudioProperties::ReadStyle) const override
     {
-      return 0;
+      return nullptr;
     }
 
     File *createFileFromStream(IOStream *s, bool, AudioProperties::ReadStyle) const override
@@ -391,7 +391,7 @@ public:
   {
     {
       FileRef f(TEST_FILE_PATH_C("xing.mp3"));
-      CPPUNIT_ASSERT(dynamic_cast<MPEG::File *>(f.file()) != NULL);
+      CPPUNIT_ASSERT(dynamic_cast<MPEG::File *>(f.file()) != nullptr);
     }
 
     DummyResolver resolver;
@@ -399,7 +399,7 @@ public:
 
     {
       FileRef f(TEST_FILE_PATH_C("xing.mp3"));
-      CPPUNIT_ASSERT(dynamic_cast<Ogg::Vorbis::File *>(f.file()) != NULL);
+      CPPUNIT_ASSERT(dynamic_cast<Ogg::Vorbis::File *>(f.file()) != nullptr);
     }
 
     DummyStreamResolver streamResolver;
@@ -408,7 +408,7 @@ public:
     {
       FileStream s(TEST_FILE_PATH_C("xing.mp3"));
       FileRef f(&s);
-      CPPUNIT_ASSERT(dynamic_cast<MP4::File *>(f.file()) != NULL);
+      CPPUNIT_ASSERT(dynamic_cast<MP4::File *>(f.file()) != nullptr);
     }
   }
 
diff --git a/tests/test_id3v2.cpp b/tests/test_id3v2.cpp
index 10a9afb8..d931f03f 100644
--- a/tests/test_id3v2.cpp
+++ b/tests/test_id3v2.cpp
@@ -60,7 +60,7 @@ class PublicFrame : public ID3v2::Frame
   public:
     PublicFrame() : ID3v2::Frame(ByteVector("XXXX\0\0\0\0\0\0", 10)) {}
     String readStringField(const ByteVector &data, String::Type encoding,
-                           int *position = 0)
+                           int *position = nullptr)
       { return ID3v2::Frame::readStringField(data, encoding, position); }
     String toString() const override { return String(); }
     void parseFields(const ByteVector &) override {}
@@ -1242,7 +1242,7 @@ public:
     tag.removeUnsupportedProperties(properties.unsupportedData());
     CPPUNIT_ASSERT(tag.frameList("APIC").isEmpty());
     CPPUNIT_ASSERT(tag.frameList("TIPL").isEmpty());
-    CPPUNIT_ASSERT_EQUAL((ID3v2::UniqueFileIdentifierFrame *)0, ID3v2::UniqueFileIdentifierFrame::findByOwner(&tag, "http://example.com"));
+    CPPUNIT_ASSERT_EQUAL((ID3v2::UniqueFileIdentifierFrame *)nullptr, ID3v2::UniqueFileIdentifierFrame::findByOwner(&tag, "http://example.com"));
     CPPUNIT_ASSERT_EQUAL(frame6, ID3v2::UniqueFileIdentifierFrame::findByOwner(&tag, "http://musicbrainz.org"));
   }
 
diff --git a/tests/test_it.cpp b/tests/test_it.cpp
index 75afb54d..9ea64f52 100644
--- a/tests/test_it.cpp
+++ b/tests/test_it.cpp
@@ -85,7 +85,7 @@ public:
     ScopedFileCopy copy("test", ".it");
     {
       IT::File file(copy.fileName().c_str());
-      CPPUNIT_ASSERT(file.tag() != 0);
+      CPPUNIT_ASSERT(file.tag() != nullptr);
       file.tag()->setTitle(titleAfter);
       file.tag()->setComment(newComment);
       file.tag()->setTrackerName("won't be saved");
@@ -104,8 +104,8 @@ private:
     IT::Properties *p = file.audioProperties();
     Mod::Tag *t = file.tag();
 
-    CPPUNIT_ASSERT(0 != p);
-    CPPUNIT_ASSERT(0 != t);
+    CPPUNIT_ASSERT(nullptr != p);
+    CPPUNIT_ASSERT(nullptr != t);
 
     CPPUNIT_ASSERT_EQUAL( 0, p->length());
     CPPUNIT_ASSERT_EQUAL( 0, p->bitrate());
diff --git a/tests/test_mod.cpp b/tests/test_mod.cpp
index 55fd7438..7a1279ce 100644
--- a/tests/test_mod.cpp
+++ b/tests/test_mod.cpp
@@ -70,7 +70,7 @@ public:
     ScopedFileCopy copy("test", ".mod");
     {
       Mod::File file(copy.fileName().c_str());
-      CPPUNIT_ASSERT(file.tag() != 0);
+      CPPUNIT_ASSERT(file.tag() != nullptr);
       file.tag()->setTitle(titleAfter);
       file.tag()->setComment(newComment);
       CPPUNIT_ASSERT(file.save());
@@ -110,8 +110,8 @@ private:
     Mod::Properties *p = file.audioProperties();
     Mod::Tag *t = file.tag();
 
-    CPPUNIT_ASSERT(0 != p);
-    CPPUNIT_ASSERT(0 != t);
+    CPPUNIT_ASSERT(nullptr != p);
+    CPPUNIT_ASSERT(nullptr != t);
 
     CPPUNIT_ASSERT_EQUAL(0, p->length());
     CPPUNIT_ASSERT_EQUAL(0, p->bitrate());
diff --git a/tests/test_riff.cpp b/tests/test_riff.cpp
index 4db2eb9b..3da1d410 100644
--- a/tests/test_riff.cpp
+++ b/tests/test_riff.cpp
@@ -51,8 +51,8 @@ public:
   void setChunkData(const ByteVector &name, const ByteVector &data) {
     RIFF::File::setChunkData(name, data);
   };
-  TagLib::Tag* tag() const override { return 0; };
-  TagLib::AudioProperties* audioProperties() const override { return 0;};
+  TagLib::Tag* tag() const override { return nullptr; };
+  TagLib::AudioProperties* audioProperties() const override { return nullptr;};
   bool save() override { return false; };
   void removeChunk(unsigned int i) { RIFF::File::removeChunk(i); }
   void removeChunk(const ByteVector &name) { RIFF::File::removeChunk(name); }
diff --git a/tests/test_s3m.cpp b/tests/test_s3m.cpp
index fd211d22..c4451ada 100644
--- a/tests/test_s3m.cpp
+++ b/tests/test_s3m.cpp
@@ -73,7 +73,7 @@ public:
     ScopedFileCopy copy("test", ".s3m");
     {
       S3M::File file(copy.fileName().c_str());
-      CPPUNIT_ASSERT(file.tag() != 0);
+      CPPUNIT_ASSERT(file.tag() != nullptr);
       file.tag()->setTitle(titleAfter);
       file.tag()->setComment(newComment);
       file.tag()->setTrackerName("won't be saved");
@@ -95,8 +95,8 @@ private:
     S3M::Properties *p = file.audioProperties();
     Mod::Tag *t = file.tag();
 
-    CPPUNIT_ASSERT(0 != p);
-    CPPUNIT_ASSERT(0 != t);
+    CPPUNIT_ASSERT(nullptr != p);
+    CPPUNIT_ASSERT(nullptr != t);
 
     CPPUNIT_ASSERT_EQUAL( 0, p->length());
     CPPUNIT_ASSERT_EQUAL( 0, p->bitrate());
diff --git a/tests/test_xm.cpp b/tests/test_xm.cpp
index fcda4f56..5c65a3af 100644
--- a/tests/test_xm.cpp
+++ b/tests/test_xm.cpp
@@ -127,8 +127,8 @@ public:
     XM::Properties *p = file.audioProperties();
     Mod::Tag *t = file.tag();
 
-    CPPUNIT_ASSERT(0 != p);
-    CPPUNIT_ASSERT(0 != t);
+    CPPUNIT_ASSERT(nullptr != p);
+    CPPUNIT_ASSERT(nullptr != t);
 
     CPPUNIT_ASSERT_EQUAL(0, p->length());
     CPPUNIT_ASSERT_EQUAL(0, p->bitrate());
@@ -173,8 +173,8 @@ private:
     XM::Properties *p = file.audioProperties();
     Mod::Tag *t = file.tag();
 
-    CPPUNIT_ASSERT(0 != p);
-    CPPUNIT_ASSERT(0 != t);
+    CPPUNIT_ASSERT(nullptr != p);
+    CPPUNIT_ASSERT(nullptr != t);
 
     CPPUNIT_ASSERT_EQUAL(0, p->length());
     CPPUNIT_ASSERT_EQUAL(0, p->bitrate());
@@ -203,7 +203,7 @@ private:
     ScopedFileCopy copy("test", ".xm");
     {
       XM::File file(copy.fileName().c_str());
-      CPPUNIT_ASSERT(file.tag() != 0);
+      CPPUNIT_ASSERT(file.tag() != nullptr);
       file.tag()->setTitle(titleAfter);
       file.tag()->setComment(comment);
       file.tag()->setTrackerName(trackerNameAfter);