diff --git a/samples/CMakeLists.txt b/samples/CMakeLists.txt
index e6d6e906..5429df35 100644
--- a/samples/CMakeLists.txt
+++ b/samples/CMakeLists.txt
@@ -40,6 +40,7 @@ foreach(entry ${SAMPLES})
     list(APPEND APPLICATIONS ${target})
     add_test( ${target}_test ${target} )
     target_link_libraries( ${target} PRIVATE exiv2lib)
+    target_include_directories(${target} PRIVATE ${CMAKE_SOURCE_DIR}/src) # To find unused.h
     install( TARGETS ${target} RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 endforeach()
 
@@ -80,6 +81,7 @@ if( EXPAT_FOUND )
     list(APPEND APPLICATIONS geotag)
     target_link_libraries( geotag    PRIVATE exiv2lib ${EXPAT_LIBRARIES})
     target_include_directories(geotag PRIVATE ${EXPAT_INCLUDE_DIR})
+    target_include_directories(geotag PRIVATE ${CMAKE_SOURCE_DIR}/src) # To find unused.h
 
     if (WIN32)
         target_compile_definitions(geotag PRIVATE XML_STATIC)
diff --git a/samples/geotag.cpp b/samples/geotag.cpp
index d190100a..13558276 100644
--- a/samples/geotag.cpp
+++ b/samples/geotag.cpp
@@ -5,6 +5,7 @@
 // g++ geotag.cpp -o geotag -lexiv2 -lexpat
 
 #include <exiv2/exiv2.hpp>
+#include "unused.h"
 
 #include <iostream>
 #include <iomanip>
@@ -57,8 +58,6 @@ char*    realpath(const char* file,char* path);
 #define _MAX_PATH 1024
 #endif
 
-#define UNUSED(x) (void)(x)
-
 // prototypes
 class Options;
 int getFileType(const char* path ,Options& options);
@@ -849,16 +848,16 @@ int main(int argc,const char* argv[])
         }
 /*
         if ( options.verbose ) {
-        	printf("Time Dictionary\n");
-        	for ( TimeDict_i it = gTimeDict.begin() ;  it != gTimeDict.end() ; it++ ) {
-        		std::string sTime = getExifTime(it->first);
-        	    Position*   pPos  = &it->second;
-        		std::string sPos  = Position::toExifString(pPos->lat(),false,true)
-        		                  + " "
-        		                  + Position::toExifString(pPos->lon(),false,true)
-        		                  ;
-        		printf("%s %s\n",sTime.c_str(), sPos.c_str());
-        	}
+            printf("Time Dictionary\n");
+            for ( TimeDict_i it = gTimeDict.begin() ;  it != gTimeDict.end() ; it++ ) {
+                std::string sTime = getExifTime(it->first);
+                Position*   pPos  = &it->second;
+                std::string sPos  = Position::toExifString(pPos->lat(),false,true)
+                                  + " "
+                                  + Position::toExifString(pPos->lon(),false,true)
+                                  ;
+                printf("%s %s\n",sTime.c_str(), sPos.c_str());
+            }
         }
 */
         for ( size_t p = 0 ; p < gFiles.size() ; p++ ) {
diff --git a/samples/xmpsample.cpp b/samples/xmpsample.cpp
index b1978875..887057fe 100644
--- a/samples/xmpsample.cpp
+++ b/samples/xmpsample.cpp
@@ -3,6 +3,7 @@
 // Sample/test for high level XMP classes. See also addmoddel.cpp
 
 #include <exiv2/exiv2.hpp>
+#include "unused.h"
 
 #include <string>
 #include <iostream>
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9be6582b..24782a8b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -143,6 +143,7 @@ set( LIBEXIV2_PRIVATE_HDR
     tifffwd_int.hpp
     tiffimage_int.hpp
     tiffvisitor_int.hpp
+    unused.h
 )
 
 
diff --git a/src/convert.cpp b/src/convert.cpp
index 23d51d87..135b233e 100644
--- a/src/convert.cpp
+++ b/src/convert.cpp
@@ -67,10 +67,6 @@
 # include <MD5.h>
 #endif // EXV_HAVE_XMP_TOOLKIT
 
-#ifndef UNUSED
-#define UNUSED(x) (void)(x)
-#endif
-
 // *****************************************************************************
 // local declarations
 namespace {
diff --git a/src/unused.h b/src/unused.h
new file mode 100644
index 00000000..5f928782
--- /dev/null
+++ b/src/unused.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2004-2018 Exiv2 authors
+ *
+ * This program is part of the Exiv2 distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef UNUSED_H
+#define UNUSED_H
+
+#define UNUSED(x) (void)(x)
+
+#endif // UNUSED_H