diff --git a/examples/boing.c b/examples/boing.c
index 3cc09730..a2094c5f 100644
--- a/examples/boing.c
+++ b/examples/boing.c
@@ -330,7 +330,7 @@ void DrawBoingBall( void )
 /*****************************************************************************
  * Bounce the ball.
  *****************************************************************************/
-void BounceBall( double dt )
+void BounceBall( double delta_t )
 {
    GLfloat sign;
    GLfloat deg;
@@ -358,8 +358,8 @@ void BounceBall( double dt )
    }
 
    /* Update ball position */
-   ball_x += ball_x_inc * ((float)dt*ANIMATION_SPEED);
-   ball_y += ball_y_inc * ((float)dt*ANIMATION_SPEED);
+   ball_x += ball_x_inc * ((float)delta_t*ANIMATION_SPEED);
+   ball_y += ball_y_inc * ((float)delta_t*ANIMATION_SPEED);
 
   /*
    * Simulate the effects of gravity on Y movement.
diff --git a/examples/splitview.c b/examples/splitview.c
index c602d0c4..4a48a383 100644
--- a/examples/splitview.c
+++ b/examples/splitview.c
@@ -442,7 +442,6 @@ static void mouseButtonFun(GLFWwindow window, int button, int action)
 int main(void)
 {
     GLFWwindow window;
-    int width, height;
 
     // Initialise GLFW
     if (!glfwInit())
diff --git a/src/x11_joystick.c b/src/x11_joystick.c
index 444c479f..9fc921fd 100644
--- a/src/x11_joystick.c
+++ b/src/x11_joystick.c
@@ -83,7 +83,7 @@ void _glfwInitJoysticks(void)
 {
 #ifdef _GLFW_USE_LINUX_JOYSTICKS
     int  k, n, fd, joy_count;
-    char* joy_base_name;
+    const char* joy_base_name;
     char joy_dev_name[20];
     int  driver_version = 0x000800;
     char ret_data;
diff --git a/support/getopt.c b/support/getopt.c
index 712cf28a..6ff6ef99 100644
--- a/support/getopt.c
+++ b/support/getopt.c
@@ -41,7 +41,10 @@
 #include <string.h>
 #include "getopt.h"
 
-
+/* 2012-08-12 Lambert Clara <lambert.clara@yahoo.fr>
+ * 
+ * Constify third argument of getopt.
+ */
 /* 2011-07-27 Camilla Berglund <elmindreda@elmindreda.org>
  * 
  * Added _CRT_SECURE_NO_WARNINGS macro.
@@ -102,7 +105,7 @@ static int permute_argv_once()
 }
 
 
-int getopt(int argc, char** argv, char* optstr)
+int getopt(int argc, char** argv, const char* optstr)
 {
 	int c = 0;
 
diff --git a/support/getopt.h b/support/getopt.h
index 0b78650a..6d2e4afe 100644
--- a/support/getopt.h
+++ b/support/getopt.h
@@ -48,7 +48,7 @@ extern int optind;
 extern int opterr;
 extern int optopt;
 
-int getopt(int argc, char** argv, char* optstr);
+int getopt(int argc, char** argv, const char* optstr);
 
 
 #ifdef __cplusplus
diff --git a/tests/defaults.c b/tests/defaults.c
index 8ab490d3..391b4984 100644
--- a/tests/defaults.c
+++ b/tests/defaults.c
@@ -38,14 +38,14 @@
 typedef struct
 {
     int param;
-    char* ext;
-    char* name;
+    const char* ext;
+    const char* name;
 } ParamGL;
 
 typedef struct
 {
     int param;
-    char* name;
+    const char* name;
 } ParamGLFW;
 
 static ParamGL gl_params[] =
diff --git a/tests/gamma.c b/tests/gamma.c
index 7d93ed06..e74d5b43 100644
--- a/tests/gamma.c
+++ b/tests/gamma.c
@@ -37,7 +37,7 @@
 
 #define STEP_SIZE 0.1f
 
-static GLfloat gamma = 1.0f;
+static GLfloat gamma_value = 1.0f;
 
 static void usage(void)
 {
@@ -46,9 +46,9 @@ static void usage(void)
 
 static void set_gamma(float value)
 {
-    gamma = value;
-    printf("Gamma: %f\n", gamma);
-    glfwSetGamma(gamma);
+    gamma_value = value;
+    printf("Gamma: %f\n", gamma_value);
+    glfwSetGamma(gamma_value);
 }
 
 static void key_callback(GLFWwindow window, int key, int action)
@@ -67,15 +67,15 @@ static void key_callback(GLFWwindow window, int key, int action)
         case GLFW_KEY_KP_ADD:
         case GLFW_KEY_Q:
         {
-            set_gamma(gamma + STEP_SIZE);
+            set_gamma(gamma_value + STEP_SIZE);
             break;
         }
 
         case GLFW_KEY_KP_SUBTRACT:
         case GLFW_KEY_W:
         {
-            if (gamma - STEP_SIZE > 0.f)
-                set_gamma(gamma - STEP_SIZE);
+            if (gamma_value - STEP_SIZE > 0.f)
+                set_gamma(gamma_value - STEP_SIZE);
 
             break;
         }
@@ -119,10 +119,10 @@ int main(int argc, char** argv)
 
     if (mode == GLFW_FULLSCREEN)
     {
-        GLFWvidmode mode;
-        glfwGetDesktopMode(&mode);
-        width = mode.width;
-        height = mode.height;
+        GLFWvidmode desktop_mode;
+        glfwGetDesktopMode(&desktop_mode);
+        width = desktop_mode.width;
+        height = desktop_mode.height;
     }
     else
     {
diff --git a/tests/iconify.c b/tests/iconify.c
index d1a505b5..33b6f058 100644
--- a/tests/iconify.c
+++ b/tests/iconify.c
@@ -100,10 +100,10 @@ int main(int argc, char** argv)
 
     if (mode == GLFW_FULLSCREEN)
     {
-        GLFWvidmode mode;
-        glfwGetDesktopMode(&mode);
-        width = mode.width;
-        height = mode.height;
+        GLFWvidmode desktop_mode;
+        glfwGetDesktopMode(&desktop_mode);
+        width = desktop_mode.width;
+        height = desktop_mode.height;
     }
     else
     {
@@ -130,8 +130,6 @@ int main(int argc, char** argv)
 
     while (!glfwGetWindowParam(window, GLFW_CLOSE_REQUESTED))
     {
-        int width, height;
-
         if (iconified != glfwGetWindowParam(window, GLFW_ICONIFIED) ||
             active != glfwGetWindowParam(window, GLFW_ACTIVE))
         {
diff --git a/tests/modes.c b/tests/modes.c
index b5912ed7..5ce65abb 100644
--- a/tests/modes.c
+++ b/tests/modes.c
@@ -68,7 +68,7 @@ static void error_callback(int error, const char* description)
     fprintf(stderr, "Error: %s\n", description);
 }
 
-static void window_size_callback(GLFWwindow window, int width, int height)
+static void window_size_callback(GLFWwindow in_window, int width, int height)
 {
     printf("Window resized to %ix%i\n", width, height);