Set cxx11 standard as minimal required standard

- remove all the code that was specialized for cxx98 that is no more supported

.github/workflows/ubuntu-dep-apt.yml

@@ -15,7 +15,7 @@ jobs:
       matrix:
         os: [ubuntu-20.04, ubuntu-22.04]
         compiler: [ {CC: /usr/bin/gcc-9, CXX: /usr/bin/g++-9}, {CC: /usr/bin/gcc-10, CXX: /usr/bin/g++-10}, {CC: /usr/bin/clang, CXX: /usr/bin/clang++} ]
-        standard: [ 98, 11, 14, 17 ]
+        standard: [ 11, 14, 17 ]
 
     steps:
     # https://github.com/marketplace/actions/cancel-workflow-action
@@ -36,7 +36,7 @@ jobs:
     - name: Print compiler information
       run: dpkg --list | grep compiler
 
-    - name: Install dependencies for ubuntu 18.04 and 20.04
+    - name: Install dependencies for ubuntu 20.04
       if: matrix.os != 'ubuntu-22.04'
       run: sudo apt-get update && sudo apt-get install -y libx11-dev libdc1394-22-dev libv4l-dev liblapack-dev libopenblas-dev libeigen3-dev libopencv-dev nlohmann-json3-dev
 

.github/workflows/ubuntu-dep-src.yml

@@ -31,7 +31,7 @@ jobs:
     - name: Print OS information
       run: lsb_release -a
 
-    - name: Install dependencies for ubuntu 18.04 and 20.04
+    - name: Install dependencies for ubuntu 20.04
       if: matrix.os != 'ubuntu-22.04'
       run: |
         sudo apt-get update && sudo apt-get install -y libdc1394-22-dev

.github/workflows/ubuntu-ustk.yml

@@ -34,7 +34,7 @@ jobs:
     - name: Print compiler information
       run: dpkg --list | grep compiler
 
-    - name: Install dependencies for ubuntu 18.04 and 20.04
+    - name: Install dependencies for ubuntu 20.04
       if: matrix.os != 'ubuntu-22.04'
       run: sudo apt-get update && sudo apt-get install -y libx11-dev libdc1394-22-dev libv4l-dev liblapack-dev libopenblas-dev libeigen3-dev libopencv-dev nlohmann-json3-dev
 

CMakeLists.txt

@@ -551,8 +551,8 @@ VP_OPTION(USE_SOXT        SOXT        ""    "Include Coin/SoXt support"    "" OF
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 VP_OPTION(USE_THREADS     Threads     ""    "Include std::thread support"      "" ON IF NOT (WIN32 OR MINGW))
 
-# We need threads with c++11
-if((VISP_CXX_STANDARD GREATER VISP_CXX_STANDARD_98) AND NOT USE_THREADS)
+# We need threads. To be changed to make threads optional
+if(NOT USE_THREADS)
   if(Threads_FOUND)
     message(WARNING "We need std::thread. We turn USE_THREADS=ON.")
     unset(USE_THREADS)
@@ -589,38 +589,7 @@ VP_OPTION(USE_NLOHMANN_JSON  nlohmann_json QUIET "Include nlohmann json support"
 # ----------------------------------------------------------------------------
 # Handle cxx standard depending on specific 3rd parties. Should be before module parsing and VISP3rdParty.cmake include
 # ----------------------------------------------------------------------------
-# if c++ standard is not at leat c++11, force 3rd parties that require at least c++11 to OFF
-if(VISP_CXX_STANDARD LESS VISP_CXX_STANDARD_11)
-  if(USE_REALSENSE)
-     message(WARNING "librealsense 3rd party was detected and needs at least c++11 standard compiler flag while you have set c++${USE_CXX_STANDARD}. Thus we disable librealsense usage turning USE_REALSENSE=OFF.")
-     unset(USE_REALSENSE)
-     set(USE_REALSENSE OFF CACHE BOOL "Include RealSense SDK support" FORCE)
-  endif()
-  if(USE_REALSENSE2)
-     message(WARNING "librealsense2 3rd party was detected and needs at least c++11 standard compiler flag while you have set c++${USE_CXX_STANDARD}. Thus we disable librealsense2 usage turning USE_REALSENSE2=OFF.")
-     unset(USE_REALSENSE2)
-     set(USE_REALSENSE2 OFF CACHE BOOL "Include RealSense2 SDK support" FORCE)
-  endif()
-  if(USE_FRANKA)
-     message(WARNING "libfranka 3rd party was detected and needs at least c++11 standard compiler flag while you have set c++${USE_CXX_STANDARD}. Thus we disable libfranka usage turning USE_FRANKA=OFF.")
-     unset(USE_FRANKA)
-     set(USE_FRANKA OFF CACHE BOOL "Include libfranka SDK support for Franka Emika robots" FORCE)
-  endif()
-  if(USE_UR_RTDE)
-    message(WARNING "ur_rtde 3rd party was detected and needs at least c++11 standard compiler flag while you have set c++${USE_CXX_STANDARD}. Thus we disable ur_rtde usage turning USE_UR_RTDE=OFF.")
-    unset(USE_UR_RTDE)
-    set(USE_UR_RTDE OFF CACHE BOOL "Include ur_rtde SDK support for Universal Robots robots" FORCE)
-  endif()
-  if((OpenCV_VERSION VERSION_GREATER 4.0.0) OR (OpenCV_VERSION VERSION_EQUAL 4.0.0))
-    # if c++ standard is not at least 11: disable opencv 4.x usage
-    message(WARNING "OpenCV ${OpenCV_VERSION} 3rd party was detected and needs c++11 or higher compiler flag while you have set c++${USE_CXX_STANDARD}. Thus we disable OpenCV usage turning USE_OPENCV=OFF")
-    unset(USE_OPENCV)
-    set(USE_OPENCV OFF CACHE BOOL "Include OpenCV support" FORCE)
-  endif()
-  # Downgrade to cxx98 to completely disable cxx11
-  unset(CMAKE_CXX_STANDARD)
-endif()
-
+# if c++ standard is not at leat c++17, force 3rd parties that require at least c++17 to OFF
 if(VISP_CXX_STANDARD LESS VISP_CXX_STANDARD_17)
   if(USE_MAVSDK)
     message(WARNING "mavsdk 3rd party was detected and needs at least c++17 standard compiler flag while you have set c++${USE_CXX_STANDARD}. Thus we disable MAVSDK usage turning USE_MAVSDK=OFF.")
@@ -665,9 +634,9 @@ VP_OPTION(WITH_APRILTAG_BIG_FAMILY ""  ""    "Build AprilTag big family (41h12,
 VP_OPTION(WITH_ATIDAQ     ""           ""    "Build atidaq-c as built-in library"  "" ON IF USE_COMEDI AND NOT WINRT)
 VP_OPTION(WITH_CLIPPER    ""           ""    "Build clipper as built-in library"   "" ON IF USE_OPENCV)
 VP_OPTION(WITH_LAPACK     ""           ""    "Build lapack as built-in library"    "" ON IF NOT USE_LAPACK)
-VP_OPTION(WITH_QBDEVICE   ""           ""    "Build qbdevice-api as built-in library" "" ON IF (VISP_CXX_STANDARD GREATER VISP_CXX_STANDARD_98) AND (NOT WINRT) AND (NOT IOS))
-VP_OPTION(WITH_TAKKTILE2  ""           ""    "Build Right Hand takktile2 driver as built-in library"   "" ON IF (VISP_CXX_STANDARD GREATER VISP_CXX_STANDARD_98) AND (NOT WIN32) AND (NOT WINRT) AND (NOT IOS) AND (NOT ANDROID))
-VP_OPTION(WITH_CATCH2     ""           ""    "Use catch2" "" ON IF (VISP_CXX_STANDARD GREATER VISP_CXX_STANDARD_98))
+VP_OPTION(WITH_QBDEVICE   ""           ""    "Build qbdevice-api as built-in library" "" ON IF (NOT WINRT) AND (NOT IOS))
+VP_OPTION(WITH_TAKKTILE2  ""           ""    "Build Right Hand takktile2 driver as built-in library"   "" ON IF (NOT WIN32) AND (NOT WINRT) AND (NOT IOS) AND (NOT ANDROID))
+VP_OPTION(WITH_CATCH2     ""           ""    "Use catch2 for testing" "" ON)
 
 # ----------------------------------------------------------------------------
 # Check for specific functions. Should be after cxx standard detection in VISPDetectCXXStandard.cmake and potential modification depending on pcl, realsense2, libfranka

ChangeLog.txt

@@ -12,9 +12,11 @@ ViSP 3.x.x (Version in development)
     .
   - Deprecated removed
     . vpPlanarObjectDetector, vpFernClassifier classes are removed
+    . End of supporting c++98 standard. As a consequence, ViSP is no more compatible with Ubuntu 12.04
   - New features and improvements
     . Introduce applications in apps folder, a collection of useful tools that
       have a dependency to the install target
+    . Bump minimal c++ standard to c++11
   - Applications
     . Migrate eye-to-hand tutorials in apps
   - Tutorials

apps/calibration/visp-acquire-franka-calib-data.cpp

@@ -42,7 +42,7 @@
 #include <visp3/robot/vpRobotFranka.h>
 #include <visp3/sensor/vpRealSense2.h>
 
-#if defined(VISP_HAVE_REALSENSE2) && (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11) && \
+#if defined(VISP_HAVE_REALSENSE2) && \
     (defined(VISP_HAVE_X11) || defined(VISP_HAVE_GDI)) && defined(VISP_HAVE_FRANKA) && \
     defined(VISP_HAVE_MODULE_GUI) && defined(VISP_HAVE_MODULE_ROBOT) && defined(VISP_HAVE_MODULE_SENSOR) // optional
 
@@ -169,9 +169,6 @@ int main()
 #if !defined(VISP_HAVE_REALSENSE2)
   std::cout << "Install librealsense-2.x." << std::endl;
 #endif
-#if !(VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
-  std::cout << "Build ViSP with c++11 or higher compiler flag (cmake -DUSE_CXX_STANDARD=11)." << std::endl;
-#endif
 #if !defined(VISP_HAVE_FRANKA)
   std::cout << "Install libfranka." << std::endl;
 #endif

apps/calibration/visp-acquire-universal-robots-calib-data.cpp

@@ -42,7 +42,7 @@
 #include <visp3/robot/vpRobotUniversalRobots.h>
 #include <visp3/sensor/vpRealSense2.h>
 
-#if defined(VISP_HAVE_REALSENSE2) && (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11) && \
+#if defined(VISP_HAVE_REALSENSE2) && \
     (defined(VISP_HAVE_X11) || defined(VISP_HAVE_GDI)) && defined(VISP_HAVE_UR_RTDE) && \
     defined(VISP_HAVE_MODULE_GUI) && defined(VISP_HAVE_MODULE_ROBOT) && defined(VISP_HAVE_MODULE_SENSOR) // optional
 
@@ -171,9 +171,6 @@ int main()
 #if !defined(VISP_HAVE_REALSENSE2)
   std::cout << "Install librealsense-2.x." << std::endl;
 #endif
-#if !(VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
-  std::cout << "Build ViSP with c++11 or higher compiler flag (cmake -DUSE_CXX_STANDARD=11)." << std::endl;
-#endif
 #if !defined(VISP_HAVE_UR_RTDE)
   std::cout << "ViSP is not build with libur_rtde 3rd party used to control a robot from Universal Robots..."
     << std::endl;

apps/calibration/visp-compute-hand-eye-calibration.cpp

@@ -187,11 +187,9 @@ int main(int argc, const char *argv[])
     // save eMc
     std::string name_we = vpIoTools::createFilePath(vpIoTools::getParent(opt_eMc_file), vpIoTools::getNameWE(opt_eMc_file)) + ".txt";
     std::cout << std::endl << "Save transformation matrix eMc as an homogeneous matrix in: " << name_we << std::endl;
-#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
+
     std::ofstream file_eMc(name_we);
-#else
-    std::ofstream file_eMc(name_we.c_str());
-#endif
+
     eMc.save(file_eMc);
 
     vpPoseVector pose_vec(eMc);

cmake/VISPDetectCXXStandard.cmake

@@ -1,38 +1,30 @@
-set(VISP_CXX_STANDARD_98 199711L)
+set(VISP_CXX_STANDARD_98 199711L) # Keep for compat with previous releases
 set(VISP_CXX_STANDARD_11 201103L)
 set(VISP_CXX_STANDARD_14 201402L)
 set(VISP_CXX_STANDARD_17 201703L)
 
 if(DEFINED USE_CXX_STANDARD)
 
-  if(USE_CXX_STANDARD STREQUAL "98")
-      set(CMAKE_CXX_STANDARD 98)
-      set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_98})
-  elseif(USE_CXX_STANDARD STREQUAL "11")
-      set(CMAKE_CXX_STANDARD 11)
-      set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_11})
+  if(USE_CXX_STANDARD STREQUAL "11")
+    set(CMAKE_CXX_STANDARD 11)
+    set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_11})
   elseif(USE_CXX_STANDARD STREQUAL "14")
-      set(CMAKE_CXX_STANDARD 14)
-      set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_14})
+    set(CMAKE_CXX_STANDARD 14)
+    set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_14})
   elseif(USE_CXX_STANDARD STREQUAL "17")
-      set(CMAKE_CXX_STANDARD 17)
-      set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_17})
+    set(CMAKE_CXX_STANDARD 17)
+    set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_17})
   endif()
 
   set(CMAKE_CXX_EXTENSIONS OFF) # use -std=c++11 instead of -std=gnu++11
 
 else()
 
   set(AVAILABLE_CXX_STANDARD TRUE)
-  set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_98})
+  set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_11})
 
   set(CMAKE_CXX_STANDARD_REQUIRED FALSE)
 
-  if(CMAKE_CXX98_COMPILE_FEATURES)
-    set(CXX98_STANDARD_FOUND ON CACHE STRING "cxx98 standard")
-    mark_as_advanced(CXX98_STANDARD_FOUND)
-  endif()
-
   if(CMAKE_CXX11_COMPILE_FEATURES)
     # cxx11 implementation maybe incomplete especially with g++ 4.6.x.
     # That's why we check more in depth for cxx_override that is not available with g++ 4.6.3
@@ -60,8 +52,6 @@ else()
     set(USE_CXX_STANDARD "14" CACHE STRING "Selected cxx standard")
   elseif(CXX11_STANDARD_FOUND)
     set(USE_CXX_STANDARD "11" CACHE STRING "Selected cxx standard")
-  elseif(CXX98_STANDARD_FOUND)
-    set(USE_CXX_STANDARD "98" CACHE STRING "Selected cxx standard")
   else()
     set(AVAILABLE_CXX_STANDARD FALSE)
   endif()
@@ -72,9 +62,6 @@ else()
   endif()
 
   if(AVAILABLE_CXX_STANDARD)
-    if(CXX98_STANDARD_FOUND)
-      set_property(CACHE USE_CXX_STANDARD APPEND_STRING PROPERTY STRINGS "98")
-    endif()
     if(CXX11_STANDARD_FOUND)
       set_property(CACHE USE_CXX_STANDARD APPEND_STRING PROPERTY STRINGS ";11")
     endif()
@@ -85,10 +72,7 @@ else()
       set_property(CACHE USE_CXX_STANDARD APPEND_STRING PROPERTY STRINGS ";17")
     endif()
 
-    if(USE_CXX_STANDARD STREQUAL "98")
-        set(CMAKE_CXX_STANDARD 98)
-        set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_98})
-    elseif(USE_CXX_STANDARD STREQUAL "11")
+    if(USE_CXX_STANDARD STREQUAL "11")
         set(CMAKE_CXX_STANDARD 11)
         set(VISP_CXX_STANDARD ${VISP_CXX_STANDARD_11})
     elseif(USE_CXX_STANDARD STREQUAL "14")

cmake/templates/VISPConfig.cmake.in

@@ -201,9 +201,6 @@ set(VISP_HAVE_CMU1394        "@VISP_HAVE_CMU1394@")
 set(VISP_HAVE_COIN3D         "@VISP_HAVE_COIN3D@")
 set(VISP_HAVE_COIN3D_AND_GUI "@VISP_HAVE_COIN3D_AND_GUI@")
 set(VISP_HAVE_COMEDI         "@VISP_HAVE_COMEDI@")
-set(VISP_HAVE_CPP11_COMPATIBILITY "@VISP_HAVE_CXX11@") # to keep compat with previous releases
-set(VISP_HAVE_CXX11          "@VISP_HAVE_CXX11@")
-set(VISP_CXX_STANDARD_98     "@VISP_CXX_STANDARD_98@")
 set(VISP_CXX_STANDARD_11     "@VISP_CXX_STANDARD_11@")
 set(VISP_CXX_STANDARD_14     "@VISP_CXX_STANDARD_14@")
 set(VISP_CXX_STANDARD_17     "@VISP_CXX_STANDARD_17@")

cmake/templates/vpConfig.h.in

@@ -485,19 +485,13 @@
 #cmakedefine VISP_HAVE_NLOHMANN_JSON
 
 // Define c++ standard values also available in __cplusplus when gcc is used
-#define VISP_CXX_STANDARD_98 ${VISP_CXX_STANDARD_98}
+#define VISP_CXX_STANDARD_98 ${VISP_CXX_STANDARD_98} # Keep for compat with previous releases
 #define VISP_CXX_STANDARD_11 ${VISP_CXX_STANDARD_11}
 #define VISP_CXX_STANDARD_14 ${VISP_CXX_STANDARD_14}
 #define VISP_CXX_STANDARD_17 ${VISP_CXX_STANDARD_17}
 
 #define VISP_CXX_STANDARD ${VISP_CXX_STANDARD}
 
-// Defined to keep compat with previous releases when c++ 11 available
-#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
-#  define VISP_HAVE_CXX11
-#  define VISP_HAVE_CPP11_COMPATIBILITY
-#endif
-
 // Defined if isnan macro is available
 #cmakedefine VISP_HAVE_FUNC_ISNAN
 

doc/config-doxygen.in

@@ -2153,9 +2153,6 @@ PREDEFINED             = @DOXYGEN_SHOULD_SKIP_THIS@ \
                          VISP_HAVE_COIN3D \
                          VISP_HAVE_COIN3D_AND_GUI \
                          VISP_HAVE_COMEDI \
-                         VISP_HAVE_CPP11_COMPATIBILITY \
-                         VISP_HAVE_CXX11 \
-                         VISP_CXX_STANDARD_98=@VISP_CXX_STANDARD_98@ \
                          VISP_CXX_STANDARD_11=@VISP_CXX_STANDARD_11@ \
                          VISP_CXX_STANDARD_14=@VISP_CXX_STANDARD_14@ \
                          VISP_CXX_STANDARD_17=@VISP_CXX_STANDARD_17@ \

doc/tutorial/detection/tutorial-detection-object-deprecated.dox

@@ -77,7 +77,7 @@ Otherwise, the configuration must be made in the code.
 
 \snippet tutorial-detection-object-mbt-deprecated.cpp Keypoint code config
 
-We then detect keypoints in the reference image with the object we want to learn : 
+We then detect keypoints in the reference image with the object we want to learn :
 
 \snippet tutorial-detection-object-mbt-deprecated.cpp Keypoints reference detection
 
@@ -173,7 +173,7 @@ And finally, we build the reference keypoints and we set the flag append to true
 
 \subsection dep_detection_object_display_multiple_images How to display the matching when the learning is done on multiple images
 
-In this section we will explain how to display the matching between keypoints detected in the current image and their correspondances in the reference images that are used during the learning stage, as given in the next video:
+In this section we will explain how to display the matching between keypoints detected in the current image and their correspondences in the reference images that are used during the learning stage, as given in the next video:
 
 \htmlonly
 <iframe width="420" height="315" src="https://www.youtube.com/embed/q16lXMIVDbM" frameborder="0" allowfullscreen></iframe>

doc/tutorial/detection/tutorial-detection-object.dox

@@ -75,7 +75,7 @@ Otherwise, the configuration must be made in the code.
 
 \snippet tutorial-detection-object-mbt.cpp Keypoint code config
 
-We then detect keypoints in the reference image with the object we want to learn : 
+We then detect keypoints in the reference image with the object we want to learn :
 
 \snippet tutorial-detection-object-mbt.cpp Keypoints reference detection
 
@@ -171,7 +171,7 @@ And finally, we build the reference keypoints and we set the flag append to true
 
 \subsection detection_object_display_multiple_images How to display the matching when the learning is done on multiple images
 
-In this section we will explain how to display the matching between keypoints detected in the current image and their correspondances in the reference images that are used during the learning stage, as given in the next video:
+In this section we will explain how to display the matching between keypoints detected in the current image and their correspondences in the reference images that are used during the learning stage, as given in the next video:
 
 \htmlonly
 <iframe width="420" height="315" src="https://www.youtube.com/embed/q16lXMIVDbM" frameborder="0" allowfullscreen></iframe>

example/device/framegrabber/getRealSense2Info.cpp

@@ -42,7 +42,7 @@
 #include <iostream>
 #include <visp3/sensor/vpRealSense2.h>
 
-#if defined(VISP_HAVE_REALSENSE2) && (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
+#if defined(VISP_HAVE_REALSENSE2)
 
 int main()
 {
@@ -57,11 +57,13 @@ int main()
 
     if (rs.getDepthScale() != 0) // If it has depth sensor
       std::cout << "Depth scale: " << std::setprecision(std::numeric_limits<float>::max_digits10) << rs.getDepthScale()
-                << std::endl;
+      << std::endl;
 
-  } catch (const vpException &e) {
+  }
+  catch (const vpException &e) {
     std::cerr << "RealSense error " << e.what() << std::endl;
-  } catch (const std::exception &e) {
+  }
+  catch (const std::exception &e) {
     std::cerr << e.what() << std::endl;
   }
 
@@ -75,11 +77,6 @@ int main()
   std::cout << "Tip:" << std::endl;
   std::cout << "- Install librealsense2, configure again ViSP using cmake and build again this example" << std::endl;
   return EXIT_SUCCESS;
-#endif
-#if (VISP_CXX_STANDARD < VISP_CXX_STANDARD_11)
-  std::cout << "You do not build ViSP with c++11 or higher compiler flag" << std::endl;
-  std::cout << "Tip:" << std::endl;
-  std::cout << "- Configure ViSP again using cmake -DUSE_CXX_STANDARD=11, and build again this example" << std::endl;
 #endif
   return EXIT_SUCCESS;
 }

example/device/framegrabber/grabRealSense.cpp

@@ -48,7 +48,7 @@
 #include <visp3/gui/vpDisplayX.h>
 #include <visp3/sensor/vpRealSense.h>
 
-#if defined(VISP_HAVE_REALSENSE) && (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
+#if defined(VISP_HAVE_REALSENSE)
 
 // Using a thread to display the pointcloud with PCL produces a segfault on
 // OSX
@@ -113,7 +113,7 @@ vpThread::Return displayPointcloudFunction(vpThread::Args args)
 
 int main()
 {
-#if defined(VISP_HAVE_REALSENSE) && (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
+#if defined(VISP_HAVE_REALSENSE)
   try {
     vpRealSense rs;
     rs.setStreamSettings(rs::stream::color, vpRealSense::vpRsStreamParams(640, 480, rs::format::rgba8, 30));
@@ -254,11 +254,6 @@ int main()
 
 #elif !defined(VISP_HAVE_REALSENSE)
   std::cout << "This deprecated example is only working with librealsense 1.x" << std::endl;
-#elif (VISP_CXX_STANDARD < VISP_CXX_STANDARD_11)
-  std::cout << "You do not build ViSP with c++11 or higher compiler flag" << std::endl;
-  std::cout << "Tip:" << std::endl;
-  std::cout << "- Configure ViSP again using cmake -DUSE_CXX_STANDARD=11, and build again this example" << std::endl;
-  << std::endl;
 #endif
   return EXIT_SUCCESS;
 }