diff --git a/require-ess/src/asprintf.c b/require-ess/src/asprintf.c
index 009028d3f1c233aa4eb3b46dc45ae567c15f6d7b..feb942630913b1a56ccb69d43e4da04c923e286a 100644
--- a/require-ess/src/asprintf.c
+++ b/require-ess/src/asprintf.c
@@ -2,6 +2,7 @@
 /* Copyright (C) 2020-2022 European Spallation Source, ERIC */
 
 #include "asprintf.h"
+
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -20,7 +21,7 @@ int vasprintf(char **pbuffer, const char *format, va_list ap) {
 #else
 /* if we have no va_copy, we probably don't need one */
 #define ap2 ap
-#endif
+#endif // va_copy
 
 #if defined(_WIN32)
   len = _vscprintf(format, ap2);
@@ -30,7 +31,7 @@ int vasprintf(char **pbuffer, const char *format, va_list ap) {
 
 #ifdef va_copy
   va_end(ap2);
-#endif
+#endif // va_copy
 
   if (len <= 0) {
     fprintf(stderr, "vasprintf: error calculating needed size\n");
diff --git a/require-ess/src/expr.c b/require-ess/src/expr.c
index 9d10432fa0393ad5bd026b6ce1a345457c2f9284..37ade64a787133ba5eb60761485acd53d24c78b1 100644
--- a/require-ess/src/expr.c
+++ b/require-ess/src/expr.c
@@ -1,13 +1,13 @@
 /* Copyright (C) 2020 Dirk Zimoch */
 /* Copyright (C) 2020-2022 European Spallation Source, ERIC */
 
+#include "expr.h"
+
 #include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "expr.h"
-
 int exprDebug;
 
 static int parseSubExpr(const char **pp, long *v, int pr, int op);
diff --git a/require-ess/src/require.c b/require-ess/src/require.c
index 45f50aa39e96d3128dbdf1577e6b40c28658ed42..4d98b6c23786f9b84c284fa77b6e744366b28ae3 100644
--- a/require-ess/src/require.c
+++ b/require-ess/src/require.c
@@ -15,12 +15,14 @@
 /* for vasprintf and dl_iterate_phdr */
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
-#endif
-#endif
+#endif // _GNU_SOURCE
+#endif // __unix
 
 /* for 64 bit (NFS) file systems */
 #define _FILE_OFFSET_BITS 64
 
+#include "require.h"
+
 #include <ctype.h>
 #include <epicsVersion.h>
 #include <errno.h>
@@ -41,7 +43,6 @@ DBCORE_API int epicsStdCall iocshCmd(const char *cmd);
 #include <epicsStdio.h>
 #include <osiFileName.h>
 
-#include "require.h"
 #include "version.h"
 
 int requireDebug;
@@ -51,32 +52,32 @@ int requireDebug;
 #ifndef OS_CLASS
 #ifdef __linux
 #define OS_CLASS "Linux"
-#endif
+#endif // __linux
 
 #ifdef SOLARIS
 #define OS_CLASS "solaris"
-#endif
+#endif // SOLARIS
 
 #ifdef __rtems__
 #define OS_CLASS "RTEMS"
-#endif
+#endif // __rtems__
 
 #ifdef CYGWIN32
 #define OS_CLASS "cygwin32"
-#endif
+#endif // CYGWIN32
 
 #ifdef freebsd
 #define OS_CLASS "freebsd"
-#endif
+#endif // freebsd
 
 #ifdef darwin
 #define OS_CLASS "Darwin"
-#endif
+#endif // darwin
 
 #ifdef _AIX32
 #define OS_CLASS "AIX"
-#endif
-#endif
+#endif // _AIX32
+#endif // OS_CLASS
 
 #include <dlfcn.h>
 #define HMODULE void *
@@ -91,7 +92,7 @@ int requireDebug;
 #define PREFIX "lib"
 #define INFIX
 #define EXT ".so"
-#endif
+#endif // CYGWIN32
 
 #elif defined(_WIN32)
 
diff --git a/require-ess/src/strdup.c b/require-ess/src/strdup.c
index 5c19581ae55570be6419396108f24736a167ecb5..75c728fc304de7ab3db00c0581898015d79aff40 100644
--- a/require-ess/src/strdup.c
+++ b/require-ess/src/strdup.c
@@ -1,6 +1,8 @@
 /* Copyright (C) 2020 Dirk Zimoch */
 /* Copyright (C) 2020-2022 European Spallation Source, ERIC */
 
+#include "strdup.h"
+
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/require-ess/src/version.c b/require-ess/src/version.c
index 60257e7104fe3386d12467901aba09d71101f353..bd59fe80a56571ff0126a88543ca9b76cae46e75 100644
--- a/require-ess/src/version.c
+++ b/require-ess/src/version.c
@@ -1,6 +1,7 @@
 /* Copyright (C) 2020-2022 European Spallation Source, ERIC */
 
 #include "version.h"
+
 #include <regex.h>
 #include <stdio.h>
 #include <stdlib.h>