diff --git a/src/pEp/native_pEp/basic_api.hh b/src/pEp/native_pEp/basic_api.hh
index a9c951a..f4714a8 100644
--- a/src/pEp/native_pEp/basic_api.hh
+++ b/src/pEp/native_pEp/basic_api.hh
@@ -1,7 +1,8 @@
 // This file is under GNU Affero General Public License 3.0
 // see LICENSE.txt
 
-#pragma once
+#ifndef BASIC_API_HH
+#define BASIC_API_HH
 
 #include "pEpmodule.hh"
 
@@ -23,5 +24,7 @@ string export_key(Identity ident);
 string export_secret_key(Identity ident);
 void set_own_key(Identity& ident, string fpr);
 
-} // namespace PythonAdapter
-} // namespace pEp {
+} /* namespace PythonAdapter */
+} /* namespace pEp */
+
+#endif /* BASIC_API_HH */
\ No newline at end of file
diff --git a/src/pEp/native_pEp/identity.hh b/src/pEp/native_pEp/identity.hh
index d01a00c..d70133f 100644
--- a/src/pEp/native_pEp/identity.hh
+++ b/src/pEp/native_pEp/identity.hh
@@ -1,7 +1,8 @@
 // This file is under GNU Affero General Public License 3.0
 // see LICENSE.txt
 
-#pragma once
+#ifndef IDENTITY_HH
+#define IDENTITY_HH
 
 // System
 #include <boost/python.hpp>
@@ -95,6 +96,7 @@ void identity_attr(pEp_identity *&ident, object value);
 boost::python::list identitylist_attr(identity_list *&il);
 void identitylist_attr(identity_list *&il, boost::python::list value);
 
-} // namespace PythonAdapter
-} // namespace pEp {
+} /* namespace PythonAdapter */
+} /* namespace pEp */
 
+#endif /* IDENTITY_HH */
\ No newline at end of file
diff --git a/src/pEp/native_pEp/message.hh b/src/pEp/native_pEp/message.hh
index 6ccc031..dac9a73 100644
--- a/src/pEp/native_pEp/message.hh
+++ b/src/pEp/native_pEp/message.hh
@@ -1,7 +1,8 @@
 // This file is under GNU Affero General Public License 3.0
 // see LICENSE.txt
 
-#pragma once
+#ifndef MESSAGE_HH
+#define MESSAGE_HH
 
 // System
 #include <string>
@@ -147,6 +148,7 @@ public:
 Message outgoing_message(Identity me);
 Message incoming_message(string mime_text);
 
-} // namespace PythonAdapter
-} // namespace pEp {
+} /* namespace PythonAdapter */
+} /* namespace pEp */
 
+#endif /* MESSAGE_HH */
\ No newline at end of file
diff --git a/src/pEp/native_pEp/message_api.cc b/src/pEp/native_pEp/message_api.cc
index 41a49e0..6a4b76d 100644
--- a/src/pEp/native_pEp/message_api.cc
+++ b/src/pEp/native_pEp/message_api.cc
@@ -1,7 +1,6 @@
 // This file is under GNU Affero General Public License 3.0
 // see LICENSE.txt
 
-
 // Engine
 #include <pEp/pEpEngine.h>
 #include <pEp/message_api.h>
diff --git a/src/pEp/native_pEp/message_api.hh b/src/pEp/native_pEp/message_api.hh
index 5147fe3..a793d32 100644
--- a/src/pEp/native_pEp/message_api.hh
+++ b/src/pEp/native_pEp/message_api.hh
@@ -1,7 +1,8 @@
 // This file is under GNU Affero General Public License 3.0
 // see LICENSE.txt
 
-#pragma once
+#ifndef MESSAGE_API_HH
+#define MESSAGE_API_HH
 
 #include "pEpmodule.hh"
 
@@ -20,5 +21,7 @@ PEP_color _color(int rating);
 object sync_search(string name);
 object distribution_search(string name);
 
-} // namespace PythonAdapter
-} // namespace pEp {
+} /* namespace PythonAdapter */
+} /* namespace pEp */
+
+#endif /* MESSAGE_API_HH */
\ No newline at end of file
diff --git a/src/pEp/native_pEp/pEpmodule.hh b/src/pEp/native_pEp/pEpmodule.hh
index 4bfc6fa..0b72c96 100644
--- a/src/pEp/native_pEp/pEpmodule.hh
+++ b/src/pEp/native_pEp/pEpmodule.hh
@@ -1,4 +1,8 @@
-#pragma once
+// This file is under GNU Affero General Public License 3.0
+// see LICENSE.txt
+
+#ifndef PEPMODULE_HH
+#define PEPMODULE_HH
 
 // Engine
 #include <pEp/pEpEngine.h>
@@ -18,6 +22,7 @@ void _throw_status(PEP_STATUS status);
 PEP_STATUS _messageToSend(::message *msg);
 PEP_STATUS notifyHandshake(pEp_identity *me, pEp_identity *partner, sync_handshake_signal signal);
 
-} // namespace PythonAdapter
-} // namespace pEp {
+} /* namespace PythonAdapter */
+} /* namespace pEp */
 
+#endif /* PEPMODULE_HH */
\ No newline at end of file
diff --git a/src/pEp/native_pEp/str_attr.hh b/src/pEp/native_pEp/str_attr.hh
index 2a6dbf9..978d22b 100644
--- a/src/pEp/native_pEp/str_attr.hh
+++ b/src/pEp/native_pEp/str_attr.hh
@@ -1,7 +1,8 @@
 // This file is under GNU Affero General Public License 3.0
 // see LICENSE.txt
 
-#pragma once
+#ifndef STR_ATTR_HH
+#define STR_ATTR_HH
 
 // System
 #include <string>
@@ -36,6 +37,7 @@ void strdict_attr(stringpair_list_t *&spl, dict value);
 stringlist_t *to_stringlist(boost::python::list l);
 boost::python::list from_stringlist(const stringlist_t *sl);
 
-} // namespace PythonAdapter
-} // namespace pEp {
+} /* namespace PythonAdapter */
+} /* namespace pEp */
 
+#endif /* STR_ATTR_HH */
\ No newline at end of file
diff --git a/src/pEp/native_pEp/user_interface.cc b/src/pEp/native_pEp/user_interface.cc
index a21234d..22be5db 100644
--- a/src/pEp/native_pEp/user_interface.cc
+++ b/src/pEp/native_pEp/user_interface.cc
@@ -59,8 +59,7 @@ PEP_STATUS UserInterface::_notifyHandshake(
 void UserInterface::deliverHandshakeResult(int result, object identities)
 {
     identity_list *shared_identities = nullptr;
-    if (identities != boost::python::api::object() &&
-            boost::python::len(identities)) {
+    if (identities != boost::python::api::object() && boost::python::len(identities)) {
         shared_identities = new_identity_list(nullptr);
         if (!shared_identities)
             throw bad_alloc();
diff --git a/src/pEp/native_pEp/user_interface.hh b/src/pEp/native_pEp/user_interface.hh
index e222b3c..f609a41 100644
--- a/src/pEp/native_pEp/user_interface.hh
+++ b/src/pEp/native_pEp/user_interface.hh
@@ -1,7 +1,8 @@
 // This file is under GNU Affero General Public License 3.0
 // see LICENSE.txt
 
-#pragma once
+#ifndef USER_INTERFACE_HH
+#define USER_INTERFACE_HH
 
 // System
 #include <csetjmp>
@@ -52,6 +53,8 @@ public:
     );
 };
 
-} // namespace PythonAdapter
-} // namespace pEp {
+} /* namespace PythonAdapter */
+} /* namespace pEp */
+
+#endif /* USER_INTERFACE_HH */