Index: libcfa/src/concurrency/channel.hfa
===================================================================
--- libcfa/src/concurrency/channel.hfa	(revision 681d8f2b4c5a072b13aa1e839314057c84f4e832)
+++ libcfa/src/concurrency/channel.hfa	(revision 5e4a830bdb0aded77369af9666fff28f1e7d6db0)
@@ -1,2 +1,4 @@
+#pragma once
+
 #include <locks.hfa>
 
Index: libcfa/src/concurrency/clib/cfathread.h
===================================================================
--- libcfa/src/concurrency/clib/cfathread.h	(revision 681d8f2b4c5a072b13aa1e839314057c84f4e832)
+++ libcfa/src/concurrency/clib/cfathread.h	(revision 5e4a830bdb0aded77369af9666fff28f1e7d6db0)
@@ -10,7 +10,9 @@
 // Created On       : Tue Sep 22 15:31:20 2020
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Sat Feb 25 17:39:20 2023
-// Update Count     : 6
+// Last Modified On : Mon Mar 13 23:48:40 2023
+// Update Count     : 7
 //
+
+#pragma once
 
 #if defined(__cforall) || defined(__cplusplus)
Index: libcfa/src/concurrency/future.hfa
===================================================================
--- libcfa/src/concurrency/future.hfa	(revision 681d8f2b4c5a072b13aa1e839314057c84f4e832)
+++ libcfa/src/concurrency/future.hfa	(revision 5e4a830bdb0aded77369af9666fff28f1e7d6db0)
@@ -14,5 +14,5 @@
 //
 
-// #pragma once
+#pragma once
 
 #include "bits/locks.hfa"
Index: libcfa/src/concurrency/invoke.h
===================================================================
--- libcfa/src/concurrency/invoke.h	(revision 681d8f2b4c5a072b13aa1e839314057c84f4e832)
+++ libcfa/src/concurrency/invoke.h	(revision 5e4a830bdb0aded77369af9666fff28f1e7d6db0)
@@ -10,7 +10,9 @@
 // Created On       : Tue Jan 17 12:27:26 2016
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Tue Nov 29 20:42:21 2022
-// Update Count     : 56
-//
+// Last Modified On : Mon Mar 13 23:51:03 2023
+// Update Count     : 57
+//
+
+#pragma once
 
 #include "bits/containers.hfa"
Index: libcfa/src/concurrency/mutex_stmt.hfa
===================================================================
--- libcfa/src/concurrency/mutex_stmt.hfa	(revision 681d8f2b4c5a072b13aa1e839314057c84f4e832)
+++ libcfa/src/concurrency/mutex_stmt.hfa	(revision 5e4a830bdb0aded77369af9666fff28f1e7d6db0)
@@ -1,2 +1,4 @@
+#pragma once
+
 #include "bits/algorithm.hfa"
 #include "bits/defs.hfa"
Index: libcfa/src/concurrency/select.hfa
===================================================================
--- libcfa/src/concurrency/select.hfa	(revision 681d8f2b4c5a072b13aa1e839314057c84f4e832)
+++ libcfa/src/concurrency/select.hfa	(revision 5e4a830bdb0aded77369af9666fff28f1e7d6db0)
@@ -1,2 +1,4 @@
+#pragma once
+
 #include "containers/list.hfa"
 #include <stdint.h>