diff --git a/samples/cpp/tutorial_code/viz/creating_widgets.cpp b/samples/cpp/tutorial_code/viz/creating_widgets.cpp
index 9ee6c54364..db6fb489a0 100644
--- a/samples/cpp/tutorial_code/viz/creating_widgets.cpp
+++ b/samples/cpp/tutorial_code/viz/creating_widgets.cpp
@@ -24,7 +24,7 @@ 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 55a3ddee2c..4cc90febfb 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 d8713fddc1..fe26c4ebee 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 3ecead8d93..d36f4fe376 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