diff --git a/include/ucore/utils.h b/include/ucore/utils.h
index 9811e1b..614b6bc 100644
--- a/include/ucore/utils.h
+++ b/include/ucore/utils.h
@@ -2,7 +2,6 @@
 #define UC_UTILS_H_
 
 #include <stddef.h>
-#include <stdio.h>
 
 //Gnerate a compiler error if the compile time
 //constant expression fails
@@ -74,6 +73,7 @@ const typeof( ((const type *)0)->member ) *__mptr = (ptr);    \
 
 
 #ifdef DEBUG
+    //include <stdio.h> if using the TRACEF() macro
     #define TRACEF(fmt, ...)\
     do { \
         fprintf(stdout, "%s (%s)\t" fmt, UC_SRC_LOCATION,  __FUNCTION__,  ##__VA_ARGS__);\
diff --git a/src/iomux_impl.c b/src/iomux_impl.c
index 6f60744..a577b5b 100644
--- a/src/iomux_impl.c
+++ b/src/iomux_impl.c
@@ -1,6 +1,6 @@
 #include <stdlib.h>
 #include <string.h>
-#include <string.h>
+#include <stdio.h>
 #include <assert.h>
 #include "ucore/clock.h"
 #include "ucore/backtrace.h"
diff --git a/test/test_heapsort.c b/test/test_heapsort.c
index 0f23e10..3668593 100644
--- a/test/test_heapsort.c
+++ b/test/test_heapsort.c
@@ -1,4 +1,5 @@
 #include <check.h>
+#include <stdio.h>
 #include "ucore/utils.h"
 #include "ucore/heapsort.h"