diff --git a/sample/basic.cc b/sample/basic.cc
index e307b0b7..ede3770d 100644
--- a/sample/basic.cc
+++ b/sample/basic.cc
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include <cstdio>
+#include <cstdlib>
 #include <cstring>
 
 #include <GLFW/glfw3.h>
@@ -104,7 +105,7 @@ int main(int argc, const char** argv) {
   // check command-line arguments
   if (argc!=2) {
     std::printf(" USAGE:  basic modelfile\n");
-    return 0;
+    return EXIT_FAILURE;
   }
 
   // load and compile model
@@ -186,5 +187,5 @@ int main(int argc, const char** argv) {
   glfwTerminate();
 #endif
 
-  return 1;
+  return EXIT_SUCCESS;
 }
diff --git a/sample/compile.cc b/sample/compile.cc
index 14382393..f96fb63f 100644
--- a/sample/compile.cc
+++ b/sample/compile.cc
@@ -16,6 +16,7 @@
 #include <cctype>
 #include <cstddef>
 #include <cstdio>
+#include <cstdlib>
 #include <cstring>
 #include <iostream>
 
@@ -49,7 +50,7 @@ int finish(const char* msg = 0, mjModel* m = 0) {
     std::cout << msg << std::endl;
   }
 
-  return 0;
+  return EXIT_SUCCESS;
 }
 
 
diff --git a/sample/record.cc b/sample/record.cc
index 522057f0..f1e39f2e 100644
--- a/sample/record.cc
+++ b/sample/record.cc
@@ -219,7 +219,7 @@ int main(int argc, const char** argv) {
   // check command-line arguments
   if (argc < 5 || argc > 6) {
     std::printf(" USAGE:  record modelfile duration fps rgbfile [adddepth]\n");
-    return 0;
+    return EXIT_FAILURE;
   }
 
   // parse numeric arguments
@@ -321,5 +321,5 @@ int main(int argc, const char** argv) {
   closeMuJoCo();
   closeOpenGL();
 
-  return 1;
+  return EXIT_SUCCESS;
 }
diff --git a/sample/testspeed.cc b/sample/testspeed.cc
index 8074f68e..c845ffd9 100644
--- a/sample/testspeed.cc
+++ b/sample/testspeed.cc
@@ -14,6 +14,7 @@
 
 #include <chrono>
 #include <cstdio>
+#include <cstdlib>
 #include <cstring>
 #include <ratio>
 #include <string>
@@ -56,7 +57,7 @@ int finish(const char* msg = NULL, mjModel* m = NULL) {
     std::printf("%s\n", msg);
   }
 
-  return 0;
+  return EXIT_SUCCESS;
 }
 
 std::vector<mjtNum> CtrlNoise(const mjModel* m, int nsteps, mjtNum ctrlnoise) {