diff --git a/include/maxscale/worker.h b/include/maxscale/worker.h
index 11070479f..102db5466 100644
--- a/include/maxscale/worker.h
+++ b/include/maxscale/worker.h
@@ -37,14 +37,6 @@ enum mxs_worker_msg_id
     MXS_WORKER_MSG_PING
 };
 
-/**
- * Initialize the worker mechanism.
- *
- * To be called once at process startup. This will cause as many workers
- * to be created as the number of threads defined.
- */
-void mxs_worker_init();
-
 /**
  * Return the worker associated with the provided worker id.
  *
diff --git a/server/core/gateway.cc b/server/core/gateway.cc
index 1b04f1dc0..220238093 100644
--- a/server/core/gateway.cc
+++ b/server/core/gateway.cc
@@ -68,7 +68,6 @@
 #include <maxscale/utils.h>
 #include <maxscale/version.h>
 #include <maxscale/random_jkiss.h>
-#include <maxscale/worker.h>
 
 #include "maxscale/config.h"
 #include "maxscale/dcb.h"
@@ -78,6 +77,7 @@
 #include "maxscale/poll.h"
 #include "maxscale/service.h"
 #include "maxscale/statistics.h"
+#include "maxscale/worker.h"
 
 #define STRING_BUFFER_SIZE 1024
 #define PIDFD_CLOSED -1
diff --git a/server/core/maxscale/worker.h b/server/core/maxscale/worker.h
new file mode 100644
index 000000000..9d4be34f3
--- /dev/null
+++ b/server/core/maxscale/worker.h
@@ -0,0 +1,27 @@
+#pragma once
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxscale/worker.h>
+
+MXS_BEGIN_DECLS
+
+/**
+ * Initialize the worker mechanism.
+ *
+ * To be called once at process startup. This will cause as many workers
+ * to be created as the number of threads defined.
+ */
+void mxs_worker_init();
+
+MXS_END_DECLS
diff --git a/server/core/worker.c b/server/core/worker.c
index 8e5668f7c..48fff9126 100644
--- a/server/core/worker.c
+++ b/server/core/worker.c
@@ -11,7 +11,7 @@
  * Public License.
  */
 
-#include <maxscale/worker.h>
+#include "maxscale/worker.h"
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
@@ -20,24 +20,32 @@
 #include <maxscale/config.h>
 #include <maxscale/log_manager.h>
 
+/**
+ * Unit variables.
+ */
 static struct worker_unit
 {
     int          n_workers;
     MXS_WORKER** workers;
 } this_unit;
 
+/**
+ * Structure used for sending cross-thread messages.
+ */
 typedef struct worker_message
 {
-    int     id;
-    int64_t arg1;
-    void*   arg2;
+    int     id;   /*< Message id. */
+    int64_t arg1; /*< Message specific first argument. */
+    void*   arg2; /*< Message specific second argument. */
 } WORKER_MESSAGE;
 
+
 static MXS_WORKER* worker_create(int worker_id);
 static void worker_free(MXS_WORKER* worker);
 static void worker_message_handler(MXS_WORKER* worker, int msg_id, int64_t arg1, void* arg2);
 static uint32_t worker_poll_handler(MXS_POLL_DATA *data, int worker_id, uint32_t events);
 
+
 void mxs_worker_init()
 {
     this_unit.n_workers = config_threadcount();