diff --git a/include/exiv2/slice.hpp b/include/exiv2/slice.hpp
index c533d231..f6cbfa24 100644
--- a/include/exiv2/slice.hpp
+++ b/include/exiv2/slice.hpp
@@ -248,7 +248,6 @@ namespace Exiv2
 
             const value_type& at(size_t index) const
             {
-                // TODO: use using base_type::at once we have C++11
                 return base_type::at(index);
             }
 
@@ -412,8 +411,7 @@ namespace Exiv2
              */
             PtrSliceStorage(storage_type ptr, size_t /*begin*/, size_t /*end*/) : data_(ptr)
             {
-                // TODO: change this to nullptr once we use C++11
-                if (ptr == NULL) {
+                if (!ptr) {
                     throw std::invalid_argument("Null pointer passed to slice constructor");
                 }
             }
diff --git a/samples/exifprint.cpp b/samples/exifprint.cpp
index 1a7e8f67..65ff5e47 100644
--- a/samples/exifprint.cpp
+++ b/samples/exifprint.cpp
@@ -29,7 +29,7 @@
 static const Exiv2::TagInfo* findTag(const Exiv2::TagInfo* pList,uint16_t tag)
 {
     while ( pList->tag_ != 0xffff && pList->tag_ != tag ) pList++;
-    return  pList->tag_ != 0xffff  ? pList : NULL;
+    return pList->tag_ != 0xffff ? pList : nullptr;
 }
 
 
diff --git a/src/basicio.cpp b/src/basicio.cpp
index 921f570e..bb1744d2 100644
--- a/src/basicio.cpp
+++ b/src/basicio.cpp
@@ -375,7 +375,8 @@ namespace Exiv2 {
                 if (hKernel) {
                     ReplaceFileA_t pfcn_ReplaceFileA = (ReplaceFileA_t)GetProcAddress(hKernel, "ReplaceFileA");
                     if (pfcn_ReplaceFileA) {
-                        BOOL ret = pfcn_ReplaceFileA(pf, fileIo->path().c_str(), NULL, REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL);
+                        BOOL ret = pfcn_ReplaceFileA(pf, fileIo->path().c_str(), nullptr,
+                                                     REPLACEFILE_IGNORE_MERGE_ERRORS, nullptr, nullptr);
                         if (ret == 0) {
                             if (GetLastError() == ERROR_FILE_NOT_FOUND) {
                                 fs::rename(fileIo->path().c_str(), pf);
@@ -1834,7 +1835,8 @@ namespace Exiv2 {
     size_t curlWriter(char* data, size_t size, size_t nmemb,
                       std::string* writerData)
     {
-        if (writerData == NULL) return 0;
+        if (writerData == nullptr)
+            return 0;
         writerData->append(data, size*nmemb);
         return size * nmemb;
     }
diff --git a/src/futils.cpp b/src/futils.cpp
index 4640df80..34f76f39 100644
--- a/src/futils.cpp
+++ b/src/futils.cpp
@@ -354,28 +354,28 @@ namespace Exiv2 {
     {
         std::string ret("unknown");
     #if defined(WIN32)
-        HANDLE processHandle = NULL;
+        HANDLE processHandle = nullptr;
         processHandle = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, GetCurrentProcessId());
-        if (processHandle != NULL) {
+        if (processHandle) {
             TCHAR filename[MAX_PATH];
-            if (GetModuleFileNameEx(processHandle, NULL, filename, MAX_PATH) != 0) {
+            if (GetModuleFileNameEx(processHandle, nullptr, filename, MAX_PATH) != 0) {
                 ret = filename;
             }
             CloseHandle(processHandle);
         }
-    #elif defined(__APPLE__)
-    #ifdef EXV_HAVE_LIBPROC_H
+#elif defined(__APPLE__)
+#ifdef EXV_HAVE_LIBPROC_H
         const int pid = getpid();
         char pathbuf[PROC_PIDPATHINFO_MAXSIZE];
         if (proc_pidpath (pid, pathbuf, sizeof(pathbuf)) > 0) {
             ret = pathbuf;
         }
-    #endif
-    #elif defined(__FreeBSD__)
+#endif
+#elif defined(__FreeBSD__)
         unsigned int       n;
         char               buffer[PATH_MAX] = {};
         struct procstat*   procstat = procstat_open_sysctl();
-        struct kinfo_proc* procs    = procstat ? procstat_getprocs(procstat, KERN_PROC_PID, getpid(), &n) : NULL;
+        struct kinfo_proc* procs = procstat ? procstat_getprocs(procstat, KERN_PROC_PID, getpid(), &n) : nullptr;
         if ( procs ) {
             procstat_getpathname(procstat, procs, buffer, PATH_MAX);
             ret = std::string(buffer);
@@ -383,7 +383,7 @@ namespace Exiv2 {
         // release resources
         if ( procs    ) procstat_freeprocs(procstat, procs);
         if ( procstat ) procstat_close(procstat);
-    #elif defined(__sun__)
+#elif defined(__sun__)
         // https://stackoverflow.com/questions/47472762/on-solaris-how-to-get-the-full-path-of-executable-of-running-process-programatic        
         const char* proc = Internal::stringFormat("/proc/%d/path/a.out",getpid()).c_str();
         char        path[500];
@@ -392,7 +392,7 @@ namespace Exiv2 {
             path[l]=0;
             ret = path;
         }
-    #elif defined(__unix__)
+#elif defined(__unix__)
         // http://stackoverflow.com/questions/606041/how-do-i-get-the-path-of-a-process-in-unix-linux
         char path[500];
         ssize_t l = readlink ("/proc/self/exe", path,sizeof(path)-1);
@@ -400,7 +400,7 @@ namespace Exiv2 {
             path[l]=0;
             ret = path;
         }
-    #endif
+#endif
 
         const size_t idxLastSeparator = ret.find_last_of(EXV_SEPARATOR_STR);
         return ret.substr(0, idxLastSeparator);
diff --git a/src/makernote_int.cpp b/src/makernote_int.cpp
index 10707a78..cd638cfa 100644
--- a/src/makernote_int.cpp
+++ b/src/makernote_int.cpp
@@ -81,7 +81,7 @@ namespace Exiv2::Internal {
 
 #if defined(_MSC_VER) || defined(__MINGW__)
             char buffer[1024];
-            if (SUCCEEDED(SHGetFolderPathA(NULL, CSIDL_PROFILE, NULL, 0, buffer))) {
+            if (SUCCEEDED(SHGetFolderPathA(nullptr, CSIDL_PROFILE, nullptr, 0, buffer))) {
                 currentPath = buffer;
             }
 #else
diff --git a/src/tiffcomposite_int.cpp b/src/tiffcomposite_int.cpp
index d72dcba1..d3c07f73 100644
--- a/src/tiffcomposite_int.cpp
+++ b/src/tiffcomposite_int.cpp
@@ -1522,7 +1522,7 @@ namespace Exiv2::Internal {
             if (component->tag() == 0x014a) {
                 // Hack: delay writing of sub-IFD image data to get the order correct
 #ifndef SUPPRESS_WARNINGS
-                if (pSubIfd != 0) {
+                if (pSubIfd) {
                     EXV_ERROR << "Multiple sub-IFD image data tags found\n";
                 }
 #endif
diff --git a/src/version.cpp b/src/version.cpp
index e14648ac..1616341b 100644
--- a/src/version.cpp
+++ b/src/version.cpp
@@ -155,8 +155,8 @@ static std::vector<std::string> getLoadedLibraries()
     if ( isatty(STDIN_FILENO) ) {
         unsigned int n;
         struct procstat*      procstat = procstat_open_sysctl();
-        struct kinfo_proc*    procs    = procstat ? procstat_getprocs(procstat, KERN_PROC_PID, getpid(), &n) : NULL;
-        struct filestat_list* files    = procs    ? procstat_getfiles(procstat, procs, true)                 : NULL;
+        struct kinfo_proc* procs = procstat ? procstat_getprocs(procstat, KERN_PROC_PID, getpid(), &n) : nullptr;
+        struct filestat_list* files = procs ? procstat_getfiles(procstat, procs, true) : nullptr;
         if ( files ) {
             filestat* entry;
             STAILQ_FOREACH(entry, files, next) {
diff --git a/src/xmp.cpp b/src/xmp.cpp
index 47d96531..12a1eb7e 100644
--- a/src/xmp.cpp
+++ b/src/xmp.cpp
@@ -570,28 +570,28 @@ namespace Exiv2 {
             pLockData_ = pLockData;
             initialized_ = SXMPMeta::Initialize();
 #ifdef EXV_ADOBE_XMPSDK
-            SXMPMeta::RegisterNamespace("http://ns.adobe.com/lightroom/1.0/", "lr",NULL);
-            SXMPMeta::RegisterNamespace("http://rs.tdwg.org/dwc/index.htm", "dwc",NULL);
-            SXMPMeta::RegisterNamespace("http://purl.org/dc/terms/", "dcterms",NULL);
-            SXMPMeta::RegisterNamespace("http://www.digikam.org/ns/1.0/", "digiKam",NULL);
-            SXMPMeta::RegisterNamespace("http://www.digikam.org/ns/kipi/1.0/", "kipi",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.0/", "MicrosoftPhoto",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.acdsee.com/iptc/1.0/", "acdsee",NULL);
-            SXMPMeta::RegisterNamespace("http://iptc.org/std/Iptc4xmpExt/2008-02-29/", "iptcExt",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.useplus.org/ldf/xmp/1.0/", "plus",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.iview-multimedia.com/mediapro/1.0/", "mediapro",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/expressionmedia/1.0/", "expressionmedia",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.2/", "MP",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.2/t/RegionInfo#", "MPRI",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.2/t/Region#", "MPReg",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.google.com/photos/1.0/panorama/", "GPano",NULL);
-            SXMPMeta::RegisterNamespace("http://www.metadataworkinggroup.com/schemas/regions/", "mwg-rs",NULL);
-            SXMPMeta::RegisterNamespace("http://www.metadataworkinggroup.com/schemas/keywords/", "mwg-kw",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.adobe.com/xmp/sType/Area#", "stArea",NULL);
-            SXMPMeta::RegisterNamespace("http://cipa.jp/exif/1.0/", "exifEX",NULL);
-            SXMPMeta::RegisterNamespace("http://ns.adobe.com/camera-raw-saved-settings/1.0/", "crss",NULL);
-            SXMPMeta::RegisterNamespace("http://www.audio/", "audio",NULL);
-            SXMPMeta::RegisterNamespace("http://www.video/", "video",NULL);
+            SXMPMeta::RegisterNamespace("http://ns.adobe.com/lightroom/1.0/", "lr", nullptr);
+            SXMPMeta::RegisterNamespace("http://rs.tdwg.org/dwc/index.htm", "dwc", nullptr);
+            SXMPMeta::RegisterNamespace("http://purl.org/dc/terms/", "dcterms", nullptr);
+            SXMPMeta::RegisterNamespace("http://www.digikam.org/ns/1.0/", "digiKam", nullptr);
+            SXMPMeta::RegisterNamespace("http://www.digikam.org/ns/kipi/1.0/", "kipi", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.0/", "MicrosoftPhoto", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.acdsee.com/iptc/1.0/", "acdsee", nullptr);
+            SXMPMeta::RegisterNamespace("http://iptc.org/std/Iptc4xmpExt/2008-02-29/", "iptcExt", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.useplus.org/ldf/xmp/1.0/", "plus", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.iview-multimedia.com/mediapro/1.0/", "mediapro", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/expressionmedia/1.0/", "expressionmedia", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.2/", "MP", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.2/t/RegionInfo#", "MPRI", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.microsoft.com/photo/1.2/t/Region#", "MPReg", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.google.com/photos/1.0/panorama/", "GPano", nullptr);
+            SXMPMeta::RegisterNamespace("http://www.metadataworkinggroup.com/schemas/regions/", "mwg-rs", nullptr);
+            SXMPMeta::RegisterNamespace("http://www.metadataworkinggroup.com/schemas/keywords/", "mwg-kw", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.adobe.com/xmp/sType/Area#", "stArea", nullptr);
+            SXMPMeta::RegisterNamespace("http://cipa.jp/exif/1.0/", "exifEX", nullptr);
+            SXMPMeta::RegisterNamespace("http://ns.adobe.com/camera-raw-saved-settings/1.0/", "crss", nullptr);
+            SXMPMeta::RegisterNamespace("http://www.audio/", "audio", nullptr);
+            SXMPMeta::RegisterNamespace("http://www.video/", "video", nullptr);
 #else
             SXMPMeta::RegisterNamespace("http://ns.adobe.com/lightroom/1.0/", "lr");
             SXMPMeta::RegisterNamespace("http://rs.tdwg.org/dwc/index.htm", "dwc");
@@ -700,7 +700,7 @@ namespace Exiv2 {
             AutoLock autoLock(xmpLockFct_, pLockData_);
             SXMPMeta::DeleteNamespace(ns.c_str());
 #ifdef EXV_ADOBE_XMPSDK
-            SXMPMeta::RegisterNamespace(ns.c_str(), prefix.c_str(),NULL);
+            SXMPMeta::RegisterNamespace(ns.c_str(), prefix.c_str(), nullptr);
 #else
             SXMPMeta::RegisterNamespace(ns.c_str(), prefix.c_str());
 #endif