diff --git a/libraries/AP_HAL/examples/AnalogIn/AnalogIn.cpp b/libraries/AP_HAL/examples/AnalogIn/AnalogIn.cpp
index 873a213cff..8e72399c86 100644
--- a/libraries/AP_HAL/examples/AnalogIn/AnalogIn.cpp
+++ b/libraries/AP_HAL/examples/AnalogIn/AnalogIn.cpp
@@ -1,24 +1,27 @@
 #include <AP_HAL/AP_HAL.h>
 
+void setup();
+void loop();
+
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 AP_HAL::AnalogSource* ch;
 
-void setup (void) {
+void setup(void) {
     hal.console->printf("Starting AP_HAL::AnalogIn test\r\n");
     ch = hal.analogin->channel(0);
 }
 
 static int8_t pin;
 
-void loop (void) 
+void loop(void)
 {
-    float v  = ch->voltage_average(); 
+    float v  = ch->voltage_average();
     if (pin == 0) {
-	    hal.console->printf("\n");
+        hal.console->printf("\n");
     }
     hal.console->printf("[%u %.3f] ",
-			  (unsigned)pin, v);
+              (unsigned)pin, (double)v);
     pin = (pin+1) % 16;
     ch->set_pin(pin);
     hal.scheduler->delay(100);
diff --git a/libraries/AP_HAL/examples/Printf/Printf.cpp b/libraries/AP_HAL/examples/Printf/Printf.cpp
index c567f480ed..94189a59f7 100644
--- a/libraries/AP_HAL/examples/Printf/Printf.cpp
+++ b/libraries/AP_HAL/examples/Printf/Printf.cpp
@@ -1,6 +1,9 @@
 #include <AP_Common/AP_Common.h>
 #include <AP_HAL/AP_HAL.h>
 
+void setup();
+void loop();
+
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 void setup(void) {
@@ -51,7 +54,7 @@ static void test_printf(void)
     uint8_t failures = 0;
     hal.console->printf("Running printf tests\n");
     for (i=0; i < ARRAY_SIZE(float_tests); i++) {
-        int ret = hal.util->snprintf(buf, sizeof(buf), float_tests[i].fmt, float_tests[i].v);
+        int ret = hal.util->snprintf(buf, sizeof(buf), float_tests[i].fmt, (double)float_tests[i].v);
         if (strcmp(buf, float_tests[i].result) != 0) {
             hal.console->printf("Failed float_tests[%u] '%s' -> '%s' should be '%s'\n",
                                 (unsigned)i,
diff --git a/libraries/AP_HAL/examples/RCInput/RCInput.cpp b/libraries/AP_HAL/examples/RCInput/RCInput.cpp
index 08a26acf0d..3c2819428f 100644
--- a/libraries/AP_HAL/examples/RCInput/RCInput.cpp
+++ b/libraries/AP_HAL/examples/RCInput/RCInput.cpp
@@ -4,14 +4,17 @@
 #include <AP_Common/AP_Common.h>
 #include <AP_HAL/AP_HAL.h>
 
+void setup();
+void loop();
+
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 #define MAX_CHANNELS 16
 
-static uint8_t max_channels_display = 8;  //Set to 0 for display numbers of channels detected.
+static uint8_t max_channels_display = 8;  // Set to 0 for display numbers of channels detected.
 static uint16_t last_value[MAX_CHANNELS];
 
-void setup(void) 
+void setup(void)
 {
     hal.console->printf("Starting RCInput test\n");
 }
@@ -19,11 +22,11 @@ void setup(void)
 void loop(void)
 {
     bool changed = false;
-    uint8_t nchannels = hal.rcin->num_channels(); //Get the numbers channels detected by RC_INPUT.
+    uint8_t nchannels = hal.rcin->num_channels();  // Get the numbers channels detected by RC_INPUT.
     if (nchannels > MAX_CHANNELS) {
         nchannels = MAX_CHANNELS;
     }
-    if (nchannels != 0) {  //If channels detected, process.
+    if (nchannels != 0) {  // If channels detected, process.
         for (uint8_t i = 0; i < nchannels; i++) {
             uint16_t v = hal.rcin->read(i);
             if (last_value[i] != v) {
diff --git a/libraries/AP_HAL/examples/RCInputToRCOutput/RCInputToRCOutput.cpp b/libraries/AP_HAL/examples/RCInputToRCOutput/RCInputToRCOutput.cpp
index fb9f00e340..962ef8dfb5 100644
--- a/libraries/AP_HAL/examples/RCInputToRCOutput/RCInputToRCOutput.cpp
+++ b/libraries/AP_HAL/examples/RCInputToRCOutput/RCInputToRCOutput.cpp
@@ -6,6 +6,9 @@
 
 #include <AP_HAL/AP_HAL.h>
 
+void setup();
+void loop();
+
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 #define MAX_CHANNELS 14
@@ -13,38 +16,38 @@ const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 static uint8_t max_channels = 0;
 static uint16_t last_value[MAX_CHANNELS];
 
-void setup(void) 
+void setup(void)
 {
     hal.console->printf("Starting RCInputToRCOutput test\n");
 
-    for(uint8_t i = 0; i < MAX_CHANNELS; i++) {
+    for (uint8_t i = 0; i < MAX_CHANNELS; i++) {
         hal.rcout->enable_ch(i);
     }
 }
 
-void loop(void) 
+void loop(void)
 {
     bool changed = false;
     uint8_t nchannels = hal.rcin->num_channels();
 
-    if(nchannels > MAX_CHANNELS) {
+    if (nchannels > MAX_CHANNELS) {
        nchannels = MAX_CHANNELS;
     }
 
-    for(uint8_t i = 0; i < nchannels; i++) {
+    for (uint8_t i = 0; i < nchannels; i++) {
         uint16_t v = hal.rcin->read(i);
-        if(last_value[i] != v) {
+        if (last_value[i] != v) {
             hal.rcout->write(i, v);
             changed = true;
             last_value[i] = v;
         }
-        if(i > max_channels) {
+        if (i > max_channels) {
             max_channels = i;
         }
     }
-    if(changed) {
-        for(uint8_t i = 0; i < max_channels; i++) {
-            hal.console->printf("%2u:%04u ", (unsigned)i + 1, (unsigned)last_value[i]);
+    if (changed) {
+        for (uint8_t i = 0; i < max_channels; i++) {
+            hal.console->printf("%2u:%04u ", (unsigned)(i + 1), (unsigned)last_value[i]);
         }
         hal.console->printf("\n");
     }
diff --git a/libraries/AP_HAL/examples/RCOutput/RCOutput.cpp b/libraries/AP_HAL/examples/RCOutput/RCOutput.cpp
index 6c456bac14..f84dfc8d37 100644
--- a/libraries/AP_HAL/examples/RCOutput/RCOutput.cpp
+++ b/libraries/AP_HAL/examples/RCOutput/RCOutput.cpp
@@ -4,12 +4,15 @@
 
 #include <AP_HAL/AP_HAL.h>
 
+void setup();
+void loop();
+
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
-void setup (void) 
+void setup (void)
 {
     hal.console->printf("Starting AP_HAL::RCOutput test\n");
-    for (uint8_t i=0; i<14; i++) {
+    for (uint8_t i = 0; i< 14; i++) {
         hal.rcout->enable_ch(i);
     }
 }
@@ -17,10 +20,9 @@ void setup (void)
 static uint16_t pwm = 1500;
 static int8_t delta = 1;
 
-void loop (void) 
+void loop (void)
 {
-    uint8_t i;
-    for (i=0; i<14; i++) {
+    for (uint8_t i=0; i < 14; i++) {
         hal.rcout->write(i, pwm);
         pwm += delta;
         if (delta > 0 && pwm >= 2000) {
diff --git a/libraries/AP_HAL/examples/RCOutput2/RCOutput.cpp b/libraries/AP_HAL/examples/RCOutput2/RCOutput.cpp
index 75788569bb..588632605d 100644
--- a/libraries/AP_HAL/examples/RCOutput2/RCOutput.cpp
+++ b/libraries/AP_HAL/examples/RCOutput2/RCOutput.cpp
@@ -6,6 +6,10 @@
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Menu/AP_Menu.h>
 
+void setup();
+void loop();
+void drive(uint16_t hz_speed);
+
 #define MENU_FUNC(func) FUNCTOR_BIND(&commands, &Menu_Commands::func, int8_t, uint8_t, const Menu::arg *)
 
 #define ESC_HZ     490
diff --git a/libraries/AP_HAL/examples/Storage/Storage.cpp b/libraries/AP_HAL/examples/Storage/Storage.cpp
index 95f01039e1..5901c81b0e 100644
--- a/libraries/AP_HAL/examples/Storage/Storage.cpp
+++ b/libraries/AP_HAL/examples/Storage/Storage.cpp
@@ -4,6 +4,9 @@
 
 #include <AP_HAL/AP_HAL.h>
 
+void setup();
+void loop();
+
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 AP_HAL::Storage *st;
@@ -20,14 +23,13 @@ void setup(void)
       Calculate XOR of the full conent of memory
       Do it by block of 8 bytes
     */
-    unsigned int i, j;
     unsigned char buff[8], XOR_res = 0;
 
-    for(i = 0; i < HAL_STORAGE_SIZE; i += 8)
-    {
+    for (uint32_t i = 0; i < HAL_STORAGE_SIZE; i += 8) {
         st->read_block((void *) buff, i, 8);
-        for(j = 0; j < 8; j++)
+        for(uint32_t j = 0; j < 8; j++) {
             XOR_res ^= buff[j];
+        }
     }
 
     /*
diff --git a/libraries/AP_HAL/examples/UART_test/UART_test.cpp b/libraries/AP_HAL/examples/UART_test/UART_test.cpp
index 3afbc31016..f4586a2eb8 100644
--- a/libraries/AP_HAL/examples/UART_test/UART_test.cpp
+++ b/libraries/AP_HAL/examples/UART_test/UART_test.cpp
@@ -8,6 +8,9 @@
 #include <stdio.h>
 #endif
 
+void setup();
+void loop();
+
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 /*
@@ -23,16 +26,16 @@ static void setup_uart(AP_HAL::UARTDriver *uart, const char *name)
 }
 
 
-void setup(void) 
+void setup(void)
 {
     /*
       start all UARTs at 57600 with default buffer sizes
      */
-    setup_uart(hal.uartA, "uartA"); // console
-    setup_uart(hal.uartB, "uartB"); // 1st GPS
-    setup_uart(hal.uartC, "uartC"); // telemetry 1
-    setup_uart(hal.uartD, "uartD"); // telemetry 2
-    setup_uart(hal.uartE, "uartE"); // 2nd GPS
+    setup_uart(hal.uartA, "uartA");  // console
+    setup_uart(hal.uartB, "uartB");  // 1st GPS
+    setup_uart(hal.uartC, "uartC");  // telemetry 1
+    setup_uart(hal.uartD, "uartD");  // telemetry 2
+    setup_uart(hal.uartE, "uartE");  // 2nd GPS
 }
 
 static void test_uart(AP_HAL::UARTDriver *uart, const char *name)
@@ -42,11 +45,11 @@ static void test_uart(AP_HAL::UARTDriver *uart, const char *name)
         return;
     }
     uart->printf("Hello on UART %s at %.3f seconds\n",
-                 name, AP_HAL::millis()*0.001f);
+                 name, (double)(AP_HAL::millis() * 0.001f));
 }
 
-void loop(void) 
-{	
+void loop(void)
+{
     test_uart(hal.uartA, "uartA");
     test_uart(hal.uartB, "uartB");
     test_uart(hal.uartC, "uartC");
@@ -56,7 +59,7 @@ void loop(void)
     // also do a raw printf() on some platforms, which prints to the
     // debug console
 #if HAL_OS_POSIX_IO
-    ::printf("Hello on debug console at %.3f seconds\n", AP_HAL::millis()*0.001f);
+    ::printf("Hello on debug console at %.3f seconds\n", (double)(AP_HAL::millis() * 0.001f));
 #endif
 
     hal.scheduler->delay(1000);