diff --git a/user/user.h b/user/user.h
index 04013ca..f16fe27 100644
--- a/user/user.h
+++ b/user/user.h
@@ -34,8 +34,10 @@ void printf(const char*, ...) __attribute__ ((format (printf, 1, 2)));
 char* gets(char*, int max);
 uint strlen(const char*);
 void* memset(void*, int, uint);
-void* malloc(uint);
-void free(void*);
 int atoi(const char*);
 int memcmp(const void *, const void *, uint);
 void *memcpy(void *, const void *, uint);
+
+// umalloc.c
+void* malloc(uint);
+void free(void*);