diff --git a/common/driver_interface.h b/common/driver_interface.h
index f4a6281f..0c282cf8 100644
--- a/common/driver_interface.h
+++ b/common/driver_interface.h
@@ -21,17 +21,16 @@
 #ifndef __jack_driver_interface_h__
 #define __jack_driver_interface_h__
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 #include <limits.h>
 #include "jslist.h"
 
 #include "JackCompilerDeps.h"
 #include "JackSystemDeps.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define JACK_DRIVER_NAME_MAX          15
 #define JACK_DRIVER_PARAM_NAME_MAX    15
 #define JACK_DRIVER_PARAM_STRING_MAX  127
diff --git a/common/jack/intclient.h b/common/jack/intclient.h
index d4503aee..6f256976 100644
--- a/common/jack/intclient.h
+++ b/common/jack/intclient.h
@@ -20,13 +20,13 @@
 #ifndef __jack_intclient_h__
 #define __jack_intclient_h__
 
+#include <jack/types.h>
+
 #ifdef __cplusplus
 extern "C"
 {
 #endif
 
-#include <jack/types.h>
-
 /**
  * Get an internal client's name.  This is useful when @ref
  * JackUseExactName was not specified on jack_internal_client_load()
diff --git a/common/jack/jack.h b/common/jack/jack.h
index 23850bbc..558e3a07 100644
--- a/common/jack/jack.h
+++ b/common/jack/jack.h
@@ -21,15 +21,16 @@
 #ifndef __jack_h__
 #define __jack_h__
 
+#include <jack/systemdeps.h>
+#include <jack/types.h>
+#include <jack/transport.h>
+#include <jack/weakmacros.h>
+
 #ifdef __cplusplus
 extern "C"
 {
 #endif
 
-#include <jack/systemdeps.h>
-#include <jack/types.h>
-#include <jack/transport.h>
-
 /**
  * Note: More documentation can be found in jack/types.h.
  */
@@ -46,8 +47,6 @@ extern "C"
      * <jack/weakjack.h> before jack.h.
      *************************************************************/
 
-#include <jack/weakmacros.h>
-
 /**
  * Call this function to get version of the JACK, in form of several numbers
  *
diff --git a/common/jack/midiport.h b/common/jack/midiport.h
index a6dad98c..04b60695 100644
--- a/common/jack/midiport.h
+++ b/common/jack/midiport.h
@@ -21,14 +21,13 @@
 #ifndef __JACK_MIDIPORT_H
 #define __JACK_MIDIPORT_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #include <jack/weakmacros.h>
 #include <jack/types.h>
 #include <stdlib.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 /** Type for raw event data contained in @ref jack_midi_event_t. */
 typedef unsigned char jack_midi_data_t;
diff --git a/common/jack/net.h b/common/jack/net.h
index 86db823f..44a9837e 100644
--- a/common/jack/net.h
+++ b/common/jack/net.h
@@ -20,15 +20,14 @@
 #ifndef __net_h__
 #define __net_h__
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 #include <jack/systemdeps.h>
 #include <jack/types.h>
 #include <jack/weakmacros.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define DEFAULT_MULTICAST_IP    "225.3.19.154"
 #define DEFAULT_PORT            19000
 #define DEFAULT_MTU             1500
diff --git a/common/jack/ringbuffer.h b/common/jack/ringbuffer.h
index 70985720..17ad5fc7 100644
--- a/common/jack/ringbuffer.h
+++ b/common/jack/ringbuffer.h
@@ -21,13 +21,12 @@
 #ifndef _RINGBUFFER_H
 #define _RINGBUFFER_H
 
+#include <sys/types.h>
+
 #ifdef __cplusplus
-extern "C"
-{
+extern "C" {
 #endif
 
-#include <sys/types.h>
-
 /** @file ringbuffer.h
  *
  * A set of library functions to make lock-free ringbuffers available
diff --git a/common/jack/session.h b/common/jack/session.h
index 608e622d..28049b09 100644
--- a/common/jack/session.h
+++ b/common/jack/session.h
@@ -21,13 +21,13 @@
 #ifndef __jack_session_h__
 #define __jack_session_h__
 
+#include <jack/types.h>
+#include <jack/weakmacros.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#include <jack/types.h>
-#include <jack/weakmacros.h>
-
 /**
  * @defgroup SessionClientFunctions Session API for clients.
  *
diff --git a/common/jack/statistics.h b/common/jack/statistics.h
index 28c270d0..6ddfd24e 100644
--- a/common/jack/statistics.h
+++ b/common/jack/statistics.h
@@ -21,13 +21,12 @@
 #ifndef __statistics_h__
 #define __statistics_h__
 
+#include <jack/types.h>
+
 #ifdef __cplusplus
-extern "C"
-{
+extern "C" {
 #endif
 
-#include <jack/types.h>
-
 /**
  * @return the maximum delay reported by the backend since
  * startup or reset.  When compared to the period size in usecs, this
diff --git a/common/jack/thread.h b/common/jack/thread.h
index 6537afdc..ccf5d85c 100644
--- a/common/jack/thread.h
+++ b/common/jack/thread.h
@@ -20,14 +20,14 @@
 #ifndef __jack_thread_h__
 #define __jack_thread_h__
 
+#include <jack/systemdeps.h>
+#include <jack/weakmacros.h>
+
 #ifdef __cplusplus
 extern "C"
 {
 #endif
 
-#include <jack/systemdeps.h>
-#include <jack/weakmacros.h>
-
 /* use 512KB stack per thread - the default is way too high to be feasible
  * with mlockall() on many systems */
 #define THREAD_STACK 524288
diff --git a/common/jack/transport.h b/common/jack/transport.h
index 4a39e66c..e07a0f15 100644
--- a/common/jack/transport.h
+++ b/common/jack/transport.h
@@ -21,13 +21,13 @@
 #ifndef __jack_transport_h__
 #define __jack_transport_h__
 
+#include <jack/types.h>
+#include <jack/weakmacros.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#include <jack/types.h>
-#include <jack/weakmacros.h>
-
 /**
  * @defgroup TransportControl Transport and Timebase control
  * @{
diff --git a/common/netjack_packet.h b/common/netjack_packet.h
index 63fa7729..aaa04f22 100644
--- a/common/netjack_packet.h
+++ b/common/netjack_packet.h
@@ -27,16 +27,15 @@
 #ifndef __JACK_NET_PACKET_H__
 #define __JACK_NET_PACKET_H__
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 #include <jack/jack.h>
 #include <jack/types.h>
 #include <jack/jslist.h>
 #include <jack/midiport.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // The Packet Header.
 
 #define CELT_MODE 1000   // Magic bitdepth value that indicates CELT compression
diff --git a/tests/external_metro.h b/tests/external_metro.h
index 8c618410..8d39f251 100644
--- a/tests/external_metro.h
+++ b/tests/external_metro.h
@@ -21,11 +21,6 @@
 #ifndef __external_metro__
 #define __external_metro__
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 #include <stdlib.h>
 #include <stdio.h>
 #include <errno.h>
@@ -36,6 +31,10 @@ extern "C"
 #include <jack/jack.h>
 #include <jack/transport.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
     typedef jack_default_audio_sample_t sample_t;
 
     /*!