diff --git a/samples/cpp/tutorial_code/viz/creating_widgets.cpp b/samples/cpp/tutorial_code/viz/creating_widgets.cpp
index f26c93ee66..37e9598219 100644
--- a/samples/cpp/tutorial_code/viz/creating_widgets.cpp
+++ b/samples/cpp/tutorial_code/viz/creating_widgets.cpp
@@ -32,7 +32,7 @@ using namespace std;
  * @function help
  * @brief Display instructions to use this tutorial program
  */
-void help()
+static void help()
 {
     cout
     << "--------------------------------------------------------------------------"   << endl
diff --git a/samples/cpp/tutorial_code/viz/launching_viz.cpp b/samples/cpp/tutorial_code/viz/launching_viz.cpp
index 9c636ebaf2..6309710660 100644
--- a/samples/cpp/tutorial_code/viz/launching_viz.cpp
+++ b/samples/cpp/tutorial_code/viz/launching_viz.cpp
@@ -14,7 +14,7 @@ using namespace std;
  * @function help
  * @brief Display instructions to use this tutorial program
  */
-void help()
+static void help()
 {
     cout
     << "--------------------------------------------------------------------------" << endl
diff --git a/samples/cpp/tutorial_code/viz/transformations.cpp b/samples/cpp/tutorial_code/viz/transformations.cpp
index 84cc2acf0d..84a19854c9 100644
--- a/samples/cpp/tutorial_code/viz/transformations.cpp
+++ b/samples/cpp/tutorial_code/viz/transformations.cpp
@@ -15,7 +15,7 @@ using namespace std;
  * @function help
  * @brief Display instructions to use this tutorial program
  */
-void help()
+static void help()
 {
     cout
     << "--------------------------------------------------------------------------"   << endl
@@ -31,7 +31,7 @@ void help()
  * @function cvcloud_load
  * @brief load bunny.ply
  */
-Mat cvcloud_load()
+static Mat cvcloud_load()
 {
     Mat cloud(1, 1889, CV_32FC3);
     ifstream ifs("bunny.ply");
diff --git a/samples/cpp/tutorial_code/viz/widget_pose.cpp b/samples/cpp/tutorial_code/viz/widget_pose.cpp
index 0fe9d81741..529a8422ec 100644
--- a/samples/cpp/tutorial_code/viz/widget_pose.cpp
+++ b/samples/cpp/tutorial_code/viz/widget_pose.cpp
@@ -15,7 +15,7 @@ using namespace std;
  * @function help
  * @brief Display instructions to use this tutorial program
  */
-void help()
+static void help()
 {
     cout
     << "--------------------------------------------------------------------------"   << endl