diff --git a/samples/addmoddel.cpp b/samples/addmoddel.cpp
index 69adb8ce..09080fea 100644
--- a/samples/addmoddel.cpp
+++ b/samples/addmoddel.cpp
@@ -103,9 +103,7 @@ try {
 
     // *************************************************************************
     // Finally, write the remaining Exif data to the image file
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert(image.get() != 0);
-
+    auto image = Exiv2::ImageFactory::open(file);
     image->setExifData(exifData);
     image->writeMetadata();
 
diff --git a/samples/convert-test.cpp b/samples/convert-test.cpp
index 420cf9b2..2d05f740 100644
--- a/samples/convert-test.cpp
+++ b/samples/convert-test.cpp
@@ -19,8 +19,7 @@ try {
         return 1;
     }
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-    assert(image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(argv[1]);
     image->readMetadata();
 
     Exiv2::XmpData xmpData;
diff --git a/samples/easyaccess-test.cpp b/samples/easyaccess-test.cpp
index fee22a57..ea8b7345 100644
--- a/samples/easyaccess-test.cpp
+++ b/samples/easyaccess-test.cpp
@@ -63,8 +63,7 @@ try {
         return 1;
     }
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(argv[1]);
     image->readMetadata();
     Exiv2::ExifData& ed = image->exifData();
 
diff --git a/samples/exifcomment.cpp b/samples/exifcomment.cpp
index 89f643a7..880c38ff 100644
--- a/samples/exifcomment.cpp
+++ b/samples/exifcomment.cpp
@@ -20,8 +20,7 @@ try {
         return 1;
     }
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(argv[1]);
     image->readMetadata();
     Exiv2::ExifData &exifData = image->exifData();
 
@@ -37,14 +36,10 @@ try {
       Following are a few examples of valid comments. The last one is written to
       the file.
      */
-    exifData["Exif.Photo.UserComment"]
-        = "charset=Unicode A Unicode Exif comment added with Exiv2";
-    exifData["Exif.Photo.UserComment"]
-        = "charset=Undefined An undefined Exif comment added with Exiv2";
-    exifData["Exif.Photo.UserComment"]
-        = "Another undefined Exif comment added with Exiv2";
-    exifData["Exif.Photo.UserComment"]
-        = "charset=Ascii An ASCII Exif comment added with Exiv2";
+    exifData["Exif.Photo.UserComment"] = "charset=Unicode A Unicode Exif comment added with Exiv2";
+    exifData["Exif.Photo.UserComment"] = "charset=Undefined An undefined Exif comment added with Exiv2";
+    exifData["Exif.Photo.UserComment"] = "Another undefined Exif comment added with Exiv2";
+    exifData["Exif.Photo.UserComment"] = "charset=Ascii An ASCII Exif comment added with Exiv2";
 
     std::cout << "Writing user comment '"
               << exifData["Exif.Photo.UserComment"]
diff --git a/samples/exifdata-test.cpp b/samples/exifdata-test.cpp
index 9abe339b..3ae5f6ec 100644
--- a/samples/exifdata-test.cpp
+++ b/samples/exifdata-test.cpp
@@ -23,8 +23,8 @@ try {
     }
     std::string file(argv[1]);
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
+    assert (image);
     image->readMetadata();
 
     Exiv2::ExifData &ed = image->exifData();
@@ -96,16 +96,14 @@ catch (Exiv2::AnyError& e) {
 
 void write(const std::string& file, Exiv2::ExifData& ed)
 {
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
     image->setExifData(ed);
     image->writeMetadata();
 }
 
 void print(const std::string& file)
 {
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
     image->readMetadata();
 
     Exiv2::ExifData &ed = image->exifData();
diff --git a/samples/exifdata.cpp b/samples/exifdata.cpp
index 31e7d57a..18d87940 100644
--- a/samples/exifdata.cpp
+++ b/samples/exifdata.cpp
@@ -184,8 +184,7 @@ int main(int argc,const char* argv[])
 	}
 
 	if ( !result ) try {
-		Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-		assert(image.get() != 0);
+        auto image = Exiv2::ImageFactory::open(file);
 		image->readMetadata();
 		Exiv2::ExifData &exifData = image->exifData();
 
diff --git a/samples/exifprint.cpp b/samples/exifprint.cpp
index 8d5e80cf..124f37a8 100644
--- a/samples/exifprint.cpp
+++ b/samples/exifprint.cpp
@@ -63,8 +63,7 @@ try {
         return rc;
     }
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert(image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
     image->readMetadata();
 
     Exiv2::ExifData &exifData = image->exifData();
diff --git a/samples/exifvalue.cpp b/samples/exifvalue.cpp
index f87ec599..55ceb02e 100644
--- a/samples/exifvalue.cpp
+++ b/samples/exifvalue.cpp
@@ -21,8 +21,7 @@ int main(int argc, char* const argv[])
     const char* file = argv[1];
     const char* key  = argv[2];
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert(image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
     image->readMetadata();
     Exiv2::ExifData &exifData = image->exifData();
 
diff --git a/samples/geotag.cpp b/samples/geotag.cpp
index 3fe01ec0..9a377c87 100644
--- a/samples/geotag.cpp
+++ b/samples/geotag.cpp
@@ -391,14 +391,13 @@ time_t parseTime(const char* arg,bool bAdjust)
 // West of GMT is negative (PDT = Pacific Daylight = -07:00 == -25200 seconds
 int timeZoneAdjust()
 {
-    time_t now = time(nullptr);
+    [[maybe_unused]] time_t now = time(nullptr);
     int       offset;
 
 #if   defined(_MSC_VER) || defined(__MINGW__)
     TIME_ZONE_INFORMATION TimeZoneInfo;
     GetTimeZoneInformation( &TimeZoneInfo );
     offset = - (((int)TimeZoneInfo.Bias + (int)TimeZoneInfo.DaylightBias) * 60);
-    UNUSED(now);
 #elif defined(__CYGWIN__)
     struct tm lcopy = *localtime(&now);
     time_t    gmt   =  timegm(&lcopy) ; // timegm modifies lcopy
diff --git a/samples/iotest.cpp b/samples/iotest.cpp
index ba6ee082..8a538b95 100644
--- a/samples/iotest.cpp
+++ b/samples/iotest.cpp
@@ -49,7 +49,7 @@ int main(int argc, char* const argv[])
             std::vector<Exiv2::byte> bytes (blocksize);
 
             // copy fileIn from a remote location.
-            BasicIo::UniquePtr io = Exiv2::ImageFactory::createIo(fr);
+            auto io = Exiv2::ImageFactory::createIo(fr);
             if ( io->open() != 0 ) {
                 Error(Exiv2::kerFileOpenFailed, io->path(), "rb", strError());
             }
diff --git a/samples/iptceasy.cpp b/samples/iptceasy.cpp
index ae06c3a5..99afcae0 100644
--- a/samples/iptceasy.cpp
+++ b/samples/iptceasy.cpp
@@ -37,9 +37,7 @@ try {
     std::cout << "Time sent: " << iptcData["Iptc.Envelope.TimeSent"] << "\n";
 
     // Open image file
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert (image.get() != 0);
-
+    auto image = Exiv2::ImageFactory::open(file);
     // Set IPTC data and write it to the file
     image->setIptcData(iptcData);
     image->writeMetadata();
diff --git a/samples/iptcprint.cpp b/samples/iptcprint.cpp
index 4a685a9f..f7eea57a 100644
--- a/samples/iptcprint.cpp
+++ b/samples/iptcprint.cpp
@@ -18,8 +18,7 @@ try {
         return 1;
     }
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(argv[1]);
     image->readMetadata();
 
     Exiv2::IptcData &iptcData = image->iptcData();
diff --git a/samples/iptctest.cpp b/samples/iptctest.cpp
index ed413a31..36703700 100644
--- a/samples/iptctest.cpp
+++ b/samples/iptctest.cpp
@@ -29,8 +29,7 @@ int main(int argc, char* const argv[])
             return 1;
         }
 
-        Image::UniquePtr image = ImageFactory::open(argv[1]);
-        assert (image.get() != 0);
+        auto image = ImageFactory::open(argv[1]);
         image->readMetadata();
 
         // Process commands
diff --git a/samples/largeiptc-test.cpp b/samples/largeiptc-test.cpp
index d62ae3f9..d4d5b4dc 100644
--- a/samples/largeiptc-test.cpp
+++ b/samples/largeiptc-test.cpp
@@ -28,7 +28,8 @@ int main(int argc, char* const argv[])
         if (io.open() != 0) {
             throw Exiv2::Error(Exiv2::kerDataSourceOpenFailed, io.path(), Exiv2::strError());
         }
-        Exiv2::DataBuf buf(static_cast<long>(io.size()));
+
+        Exiv2::DataBuf buf(io.size());
         std::cout << "Reading " << buf.size() << " bytes from " << data << "\n";
         const size_t readBytes = io.read(buf.data(), buf.size());
         if (readBytes != buf.size() || io.error() || io.eof()) {
@@ -36,8 +37,7 @@ int main(int argc, char* const argv[])
         }
 
         // Read metadata from file
-        Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-        assert(image.get() != 0);
+        auto image = Exiv2::ImageFactory::open(file);
         image->readMetadata();
 
         // Set Preview field to the content of the data file
diff --git a/samples/metacopy.cpp b/samples/metacopy.cpp
index ff376ac5..5062b014 100644
--- a/samples/metacopy.cpp
+++ b/samples/metacopy.cpp
@@ -34,12 +34,10 @@ try {
     auto memIo = std::make_unique<Exiv2::MemIo>();
     memIo->transfer(fileIo);
 
-    Exiv2::Image::UniquePtr readImg = Exiv2::ImageFactory::open(std::move(memIo));
-    assert(readImg.get() != 0);
+    auto readImg = Exiv2::ImageFactory::open(std::move(memIo));
     readImg->readMetadata();
 
-    Exiv2::Image::UniquePtr writeImg = Exiv2::ImageFactory::open(params.write_);
-    assert(writeImg.get() != 0);
+    auto writeImg = Exiv2::ImageFactory::open(params.write_);
     if (params.preserve_) {
         writeImg->readMetadata();
     }
diff --git a/samples/mmap-test.cpp b/samples/mmap-test.cpp
index 17133f18..a12ba7a5 100644
--- a/samples/mmap-test.cpp
+++ b/samples/mmap-test.cpp
@@ -28,8 +28,7 @@ try {
     }
     // Map it to memory
     const Exiv2::byte* pData = file.mmap();
-    auto size = static_cast<long>(file.size());
-    DataBuf buf(size);
+    DataBuf buf(file.size());
     // Read from the memory mapped region
     buf.copyBytes(0, pData, buf.size());
     // Reopen file in write mode and write to it
diff --git a/samples/mrwthumb.cpp b/samples/mrwthumb.cpp
index 8656c51b..323b0346 100644
--- a/samples/mrwthumb.cpp
+++ b/samples/mrwthumb.cpp
@@ -19,8 +19,7 @@ int main(int argc, char* const argv[])
             return 1;
         }
 
-        Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-        assert(image.get() != 0);
+        auto image = Exiv2::ImageFactory::open(argv[1]);
         image->readMetadata();
 
         Exiv2::ExifData& exifData = image->exifData();
diff --git a/samples/prevtest.cpp b/samples/prevtest.cpp
index 25960e33..f4065a3d 100644
--- a/samples/prevtest.cpp
+++ b/samples/prevtest.cpp
@@ -19,8 +19,7 @@ try {
     }
     std::string filename(argv[1]);
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(filename);
-    assert(image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(filename);
     image->readMetadata();
 
     Exiv2::PreviewManager loader(*image);
diff --git a/samples/remotetest.cpp b/samples/remotetest.cpp
index aa78988d..a08a494e 100644
--- a/samples/remotetest.cpp
+++ b/samples/remotetest.cpp
@@ -44,15 +44,13 @@ try {
     Exiv2::ExifKey key("Exif.Image.DateTime");
     exifData.add(key, v.get());
 
-    Exiv2::Image::UniquePtr writeTest = Exiv2::ImageFactory::open(file, useCurlFromExiv2TestApps);
-    assert(writeTest.get() != 0);
+    auto writeTest = Exiv2::ImageFactory::open(file, useCurlFromExiv2TestApps);
     writeTest->setExifData(exifData);
     writeTest->writeMetadata();
 
     // read the result to make sure everything fine
     std::cout << "Print out the new metadata ...\n";
-    Exiv2::Image::UniquePtr readTest = Exiv2::ImageFactory::open(file, useCurlFromExiv2TestApps);
-    assert(readTest.get() != 0);
+    auto readTest = Exiv2::ImageFactory::open(file, useCurlFromExiv2TestApps);
     readTest->readMetadata();
     Exiv2::ExifData &exifReadData = readTest->exifData();
     if (exifReadData.empty()) {
diff --git a/samples/write-test.cpp b/samples/write-test.cpp
index 14681aed..2bb1e320 100644
--- a/samples/write-test.cpp
+++ b/samples/write-test.cpp
@@ -148,8 +148,7 @@ void testCase(const std::string& file1,
     ExifKey ek(key);
 
     //Open first image
-    Image::UniquePtr image1 = ImageFactory::open(file1);
-    assert(image1.get() != 0);
+    auto image1 = ImageFactory::open(file1);
 
     // Load existing metadata
     std::cerr << "---> Reading file " << file1 << "\n";
@@ -164,8 +163,7 @@ void testCase(const std::string& file1,
     pos->setValue(value);
 
     // Open second image
-    Image::UniquePtr image2 = ImageFactory::open(file2);
-    assert(image2.get() != 0);
+    auto image2 = ImageFactory::open(file2);
 
     image2->setExifData(image1->exifData());
 
diff --git a/samples/write2-test.cpp b/samples/write2-test.cpp
index a47db8cb..a1a11690 100644
--- a/samples/write2-test.cpp
+++ b/samples/write2-test.cpp
@@ -27,19 +27,19 @@ int main(int argc, char* const argv[])
     Exiv2::ExifData ed1;
     ed1["Exif.Image.Model"] = "Test 1";
 
-    Exiv2::Value::UniquePtr v1 = Exiv2::Value::create(Exiv2::unsignedShort);
+    auto v1 = Exiv2::Value::create(Exiv2::unsignedShort);
     v1->read("160 161 162 163");
     ed1.add(Exiv2::ExifKey("Exif.Image.SamplesPerPixel"), v1.get());
 
-    Exiv2::Value::UniquePtr v2 = Exiv2::Value::create(Exiv2::signedLong);
+    auto v2 = Exiv2::Value::create(Exiv2::signedLong);
     v2->read("-2 -1 0 1");
     ed1.add(Exiv2::ExifKey("Exif.Image.XResolution"), v2.get());
 
-    Exiv2::Value::UniquePtr v3 = Exiv2::Value::create(Exiv2::signedRational);
+    auto v3 = Exiv2::Value::create(Exiv2::signedRational);
     v3->read("-2/3 -1/3 0/3 1/3");
     ed1.add(Exiv2::ExifKey("Exif.Image.YResolution"), v3.get());
 
-    Exiv2::Value::UniquePtr v4 = Exiv2::Value::create(Exiv2::undefined);
+    auto v4 = Exiv2::Value::create(Exiv2::undefined);
     v4->read("255 254 253 252");
     ed1.add(Exiv2::ExifKey("Exif.Image.WhitePoint"), v4.get());
 
@@ -66,8 +66,7 @@ int main(int argc, char* const argv[])
     print(file);
 
     std::cout <<"\n----- Non-intrusive writing of special Canon MakerNote tags\n";
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert(image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
     image->readMetadata();
 
     Exiv2::ExifData& rEd = image->exifData();
@@ -198,8 +197,7 @@ catch (Exiv2::AnyError& e) {
 
 void write(const std::string& file, Exiv2::ExifData& ed)
 {
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert(image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
 
     image->setExifData(ed);
     image->writeMetadata();
@@ -207,8 +205,7 @@ void write(const std::string& file, Exiv2::ExifData& ed)
 
 void print(const std::string& file)
 {
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(file);
-    assert(image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(file);
     image->readMetadata();
 
     Exiv2::ExifData &ed = image->exifData();
diff --git a/samples/xmpdump.cpp b/samples/xmpdump.cpp
index 30a1d1c5..27046816 100644
--- a/samples/xmpdump.cpp
+++ b/samples/xmpdump.cpp
@@ -18,8 +18,7 @@ int main(int argc, char* const argv[])
             return 1;
         }
 
-        Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-        assert(image.get() != 0);
+        auto image = Exiv2::ImageFactory::open(argv[1]);
         image->readMetadata();
 
         const std::string& xmpPacket = image->xmpPacket();
diff --git a/samples/xmpparse.cpp b/samples/xmpparse.cpp
index 5ced9765..7a3c4b70 100644
--- a/samples/xmpparse.cpp
+++ b/samples/xmpparse.cpp
@@ -16,6 +16,7 @@ try {
         std::cout << "Usage: " << argv[0] << " file\n";
         return 1;
     }
+
     Exiv2::DataBuf buf = Exiv2::readFile(argv[1]);
     std::string xmpPacket;
     xmpPacket.assign(buf.c_str(), buf.size());
diff --git a/samples/xmpprint.cpp b/samples/xmpprint.cpp
index b739122e..d31be898 100644
--- a/samples/xmpprint.cpp
+++ b/samples/xmpprint.cpp
@@ -23,8 +23,7 @@ int main(int argc, char** argv)
         return 1;
       }
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(argv[1]);
     image->readMetadata();
 
     Exiv2::XmpData &xmpData = image->xmpData();
diff --git a/samples/xmpsample.cpp b/samples/xmpsample.cpp
index e2067de5..5c67d954 100644
--- a/samples/xmpsample.cpp
+++ b/samples/xmpsample.cpp
@@ -107,7 +107,7 @@ try {
     // properties and language alternatives.
 
     // Add a simple XMP property in a known namespace
-    Exiv2::Value::UniquePtr v = Exiv2::Value::create(Exiv2::xmpText);
+    auto v = Exiv2::Value::create(Exiv2::xmpText);
     v->read("image/jpeg");
     xmpData.add(Exiv2::XmpKey("Xmp.dc.format"), v.get());
 
diff --git a/src/futils.cpp b/src/futils.cpp
index 438669e5..e5292451 100644
--- a/src/futils.cpp
+++ b/src/futils.cpp
@@ -4,6 +4,7 @@
 #include "futils.hpp"
 
 #include "config.h"
+#include "error.hpp"
 
 // + standard includes
 #include <algorithm>