diff --git a/samples/xmpsample.cpp b/samples/xmpsample.cpp
index 5c67d954..81042953 100644
--- a/samples/xmpsample.cpp
+++ b/samples/xmpsample.cpp
@@ -3,8 +3,9 @@
 
 #include <exiv2/exiv2.hpp>
 
-#include <iostream>
+#include <cassert>
 #include <cmath>
+#include <iostream>
 
 bool isEqual(float a, float b)
 {
@@ -79,7 +80,7 @@ try {
 
     [[maybe_unused]] const Exiv2::Value &getv6 = xmpData["Xmp.dc.six"].value();
     assert(getv6.toInt64() == 0);
-    assert(getv6.ok()^);
+    assert(getv6.ok());
     assert(getv6.toFloat() == 0.0f);
     assert(getv6.ok());
     assert(getv6.toRational() == Exiv2::Rational(0, 1));
diff --git a/src/bmpimage.cpp b/src/bmpimage.cpp
index 78416cfd..f60c0e25 100644
--- a/src/bmpimage.cpp
+++ b/src/bmpimage.cpp
@@ -14,6 +14,7 @@
 // + standard includes
 #include <cstring>
 #include <string>
+#include <iostream>
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/cr2image.cpp b/src/cr2image.cpp
index 546a197d..264e5b04 100644
--- a/src/cr2image.cpp
+++ b/src/cr2image.cpp
@@ -11,6 +11,8 @@
 #include "tiffcomposite_int.hpp"
 #include "tiffimage_int.hpp"
 
+#include <iostream>
+
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
diff --git a/src/crwimage.cpp b/src/crwimage.cpp
index 7b61aa57..f584cbf1 100644
--- a/src/crwimage.cpp
+++ b/src/crwimage.cpp
@@ -13,6 +13,8 @@
 #include "futils.hpp"
 #include "tags.hpp"
 
+#include <iostream>
+
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
diff --git a/src/gifimage.cpp b/src/gifimage.cpp
index 3bc4c797..4ae6976c 100644
--- a/src/gifimage.cpp
+++ b/src/gifimage.cpp
@@ -7,6 +7,8 @@
 #include "error.hpp"
 #include "futils.hpp"
 
+#include <iostream>
+
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
diff --git a/src/iptc.cpp b/src/iptc.cpp
index 25d93d15..53908c17 100644
--- a/src/iptc.cpp
+++ b/src/iptc.cpp
@@ -12,6 +12,7 @@
 
 // + standard includes
 #include <algorithm>
+#include <iostream>
 
 // *****************************************************************************
 namespace {
diff --git a/src/jp2image.cpp b/src/jp2image.cpp
index fafc0893..2d2dbbcc 100644
--- a/src/jp2image.cpp
+++ b/src/jp2image.cpp
@@ -15,6 +15,7 @@
 #include "safe_op.hpp"
 
 #include <array>
+#include <iostream>
 
 // JPEG-2000 box types
 const uint32_t kJp2BoxTypeJp2Header   = 0x6a703268; // 'jp2h'
diff --git a/src/jpgimage.cpp b/src/jpgimage.cpp
index 5edf737a..2be1c3e2 100644
--- a/src/jpgimage.cpp
+++ b/src/jpgimage.cpp
@@ -21,6 +21,8 @@
 
 #include "fff.h"
 
+#include <iostream>
+
 // *****************************************************************************
 // class member definitions
 
diff --git a/src/mrwimage.cpp b/src/mrwimage.cpp
index c529cb34..639392b0 100644
--- a/src/mrwimage.cpp
+++ b/src/mrwimage.cpp
@@ -11,6 +11,8 @@
 #include "image.hpp"
 #include "tiffimage.hpp"
 
+#include <iostream>
+
 namespace Exiv2 {
 
     MrwImage::MrwImage(BasicIo::UniquePtr io, bool /*create*/)
diff --git a/src/orfimage.cpp b/src/orfimage.cpp
index 352f27c3..3412a577 100644
--- a/src/orfimage.cpp
+++ b/src/orfimage.cpp
@@ -13,6 +13,8 @@
 #include "tiffimage.hpp"
 #include "tiffimage_int.hpp"
 
+#include <iostream>
+
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
diff --git a/src/pgfimage.cpp b/src/pgfimage.cpp
index 89eec775..daab5b3c 100644
--- a/src/pgfimage.cpp
+++ b/src/pgfimage.cpp
@@ -10,6 +10,8 @@
 #include "futils.hpp"
 #include "image.hpp"
 
+#include <iostream>
+
 // Signature from front of PGF file
 const unsigned char pgfSignature[3] = { 0x50, 0x47, 0x46 };
 
diff --git a/src/pngimage.cpp b/src/pngimage.cpp
index 6a0b9516..c1a26d6c 100644
--- a/src/pngimage.cpp
+++ b/src/pngimage.cpp
@@ -18,6 +18,8 @@
 #include "tiffimage.hpp"
 #include "types.hpp"
 
+#include <iostream>
+
 // Signature from front of PNG file
 const unsigned char pngSignature[8] = { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
 
diff --git a/src/properties.cpp b/src/properties.cpp
index e0972fca..ac8dff7a 100644
--- a/src/properties.cpp
+++ b/src/properties.cpp
@@ -11,6 +11,8 @@
 #include "value.hpp"
 #include "xmp_exiv2.hpp"
 
+#include <iostream>
+
 namespace {
 
     //! Struct used in the lookup table for pretty print functions
diff --git a/src/psdimage.cpp b/src/psdimage.cpp
index 75435dc6..13dea7c4 100644
--- a/src/psdimage.cpp
+++ b/src/psdimage.cpp
@@ -11,6 +11,8 @@
 #include "image.hpp"
 #include "jpgimage.hpp"
 
+#include <iostream>
+
 // Todo: Consolidate with existing code in struct Photoshop (jpgimage.hpp):
 //       Extend this helper to a proper class with all required functionality,
 //       then move it here or into a separate file?
diff --git a/src/rafimage.cpp b/src/rafimage.cpp
index 5e883f99..5d12fe75 100644
--- a/src/rafimage.cpp
+++ b/src/rafimage.cpp
@@ -13,6 +13,8 @@
 #include "safe_op.hpp"
 #include "tiffimage.hpp"
 
+#include <iostream>
+
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
diff --git a/src/tgaimage.cpp b/src/tgaimage.cpp
index c6115921..437c6147 100644
--- a/src/tgaimage.cpp
+++ b/src/tgaimage.cpp
@@ -9,6 +9,8 @@
 #include "futils.hpp"
 #include "image.hpp"
 
+#include <iostream>
+
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
diff --git a/src/tiffcomposite_int.cpp b/src/tiffcomposite_int.cpp
index 27b8f068..b6991c3e 100644
--- a/src/tiffcomposite_int.cpp
+++ b/src/tiffcomposite_int.cpp
@@ -11,6 +11,8 @@
 #include "error.hpp"
 #include "enforce.hpp"
 
+#include <iostream>
+
 // *****************************************************************************
 namespace {
     //! Add \em tobe - \em curr 0x00 filler bytes if necessary
diff --git a/src/tiffimage.cpp b/src/tiffimage.cpp
index 20d9a06b..bffd7ce7 100644
--- a/src/tiffimage.cpp
+++ b/src/tiffimage.cpp
@@ -12,6 +12,8 @@
 #include "tiffimage_int.hpp"
 #include "types.hpp"
 
+#include <iostream>
+
 /* --------------------------------------------------------------------------
 
    Todo:
diff --git a/src/tiffimage_int.cpp b/src/tiffimage_int.cpp
index bd04897c..eb221adf 100644
--- a/src/tiffimage_int.cpp
+++ b/src/tiffimage_int.cpp
@@ -8,6 +8,8 @@
 #include "tiffvisitor_int.hpp"
 #include "i18n.h"                // NLS support.
 
+#include <iostream>
+
 // Shortcuts for the newTiffBinaryArray templates.
 #define EXV_BINARY_ARRAY(arrayCfg, arrayDef) (newTiffBinaryArray0<&arrayCfg, EXV_COUNTOF(arrayDef), arrayDef>)
 #define EXV_SIMPLE_BINARY_ARRAY(arrayCfg) (newTiffBinaryArray1<&arrayCfg>)
diff --git a/src/tiffvisitor_int.cpp b/src/tiffvisitor_int.cpp
index bfed835d..0c2aa35e 100644
--- a/src/tiffvisitor_int.cpp
+++ b/src/tiffvisitor_int.cpp
@@ -14,6 +14,7 @@
 #include "jpgimage.hpp"
 #include "sonymn_int.hpp"
 
+#include <iostream>
 
 // *****************************************************************************
 namespace {
diff --git a/src/webpimage.cpp b/src/webpimage.cpp
index 22bf202e..ddf83ea1 100644
--- a/src/webpimage.cpp
+++ b/src/webpimage.cpp
@@ -17,6 +17,8 @@
 #include "safe_op.hpp"
 #include "types.hpp"
 
+#include <iostream>
+
 namespace {
     [[maybe_unused]] std::string binaryToHex(const uint8_t* data, size_t size)
     {
diff --git a/src/xmp.cpp b/src/xmp.cpp
index 5d19646e..e37252e3 100644
--- a/src/xmp.cpp
+++ b/src/xmp.cpp
@@ -9,6 +9,7 @@
 
 // + standard includes
 #include <algorithm>
+#include <iostream>
 
 // Adobe XMP Toolkit
 #ifdef   EXV_HAVE_XMP_TOOLKIT
diff --git a/src/xmpsidecar.cpp b/src/xmpsidecar.cpp
index 11b64148..18c4ad1e 100644
--- a/src/xmpsidecar.cpp
+++ b/src/xmpsidecar.cpp
@@ -9,6 +9,8 @@
 #include "image.hpp"
 #include "xmp_exiv2.hpp"
 
+#include <iostream>
+
 namespace {
     constexpr auto xmlHeader = "<?xpacket begin=\"\xef\xbb\xbf\" id=\"W5M0MpCehiHzreSzNTczkc9d\"?>\n";
     const auto xmlHdrCnt = static_cast<long>(std::strlen(xmlHeader));  // without the trailing 0-character