diff --git a/common/lib/advio.c b/common/lib/advio.c
index 16f3fbe2e..8cef11dec 100644
--- a/common/lib/advio.c
+++ b/common/lib/advio.c
@@ -249,7 +249,7 @@ AFILE * afopen(const char *uri, const char *mode)
 #if LIBCURL_VERSION_NUM >= 0x072000
 		curl_easy_setopt(af->curl, CURLOPT_XFERINFOFUNCTION, advio_xferinfo);
 		curl_easy_setopt(af->curl, CURLOPT_XFERINFODATA, af);
-#endif
+#endif /* LIBCURL_VERSION_NUM >= 0x072000 */
 
 	ret = adownload(af, 0);
 	if (ret)
diff --git a/common/lib/compat.c b/common/lib/compat.c
index 314fe9539..32ae8ea66 100644
--- a/common/lib/compat.c
+++ b/common/lib/compat.c
@@ -65,7 +65,7 @@ static int json_dumpfd_callback(const char *buffer, size_t size, void *data)
 
 	if (write(*dest, buffer, size) == (ssize_t)size)
 		return 0;
-#endif
+#endif /* HAVE_UNISTD_H */
 
 	return -1;
 }
@@ -74,4 +74,4 @@ int json_dumpfd(const json_t *json, int output, size_t flags)
 {
     return json_dump_callback(json, json_dumpfd_callback, (void *) &output, flags);
 }
-#endif
+#endif /* JANSSON_VERSION_HEX < 0x020A00 */
diff --git a/common/lib/kernel/rt.cpp b/common/lib/kernel/rt.cpp
index 8bf4a311a..90085c1ae 100644
--- a/common/lib/kernel/rt.cpp
+++ b/common/lib/kernel/rt.cpp
@@ -69,7 +69,7 @@ void init(int priority, int affinity)
 
 	(void) affinity;
 	(void) priority;
-#endif
+#endif /* __linux__ */
 }
 
 #ifdef __linux__
diff --git a/common/lib/task.c b/common/lib/task.c
index d3628f29a..a20d26f63 100644
--- a/common/lib/task.c
+++ b/common/lib/task.c
@@ -30,7 +30,7 @@
 
 #if PERIODIC_TASK_IMPL == TIMERFD
   #include <sys/timerfd.h>
-#endif
+#endif /* PERIODIC_TASK_IMPL */
 
 int task_init(struct task *t, double rate, int clock)
 {
@@ -46,7 +46,7 @@ int task_init(struct task *t, double rate, int clock)
 	ret = tsc_init(&t->tsc);
 	if (ret)
 		return ret;
-#endif
+#endif /* PERIODIC_TASK_IMPL */
 
 	ret = task_set_rate(t, rate);
 	if (ret)
@@ -70,8 +70,7 @@ int task_set_timeout(struct task *t, double to)
 int task_set_next(struct task *t, struct timespec *next)
 {
 
-#if PERIODIC_TASK_IMPL == RDTSC
-#else
+#if PERIODIC_TASK_IMPL != RDTSC
 	t->next = *next;
 
   #if PERIODIC_TASK_IMPL == TIMERFD
@@ -84,8 +83,8 @@ int task_set_next(struct task *t, struct timespec *next)
 	ret = timerfd_settime(t->fd, TFD_TIMER_ABSTIME, &its, NULL);
 	if (ret)
 		return ret;
-  #endif
-#endif
+  #endif /* PERIODIC_TASK_IMPL == TIMERFD */
+#endif /* PERIODIC_TASK_IMPL != RDTSC */
 
 	return 0;
 }
@@ -117,8 +116,8 @@ int task_set_rate(struct task *t, double rate)
 	ret = timerfd_settime(t->fd, 0, &its, NULL);
 	if (ret)
 		return ret;
-  #endif
-#endif
+  #endif /* PERIODIC_TASK_IMPL */
+#endif /* PERIODIC_TASK_IMPL == RDTSC */
 
 	return 0;
 }