diff --git a/libs/libc/include/fcntl.h b/libs/libc/include/fcntl.h
index dbe24b94..e60f6b55 100644
--- a/libs/libc/include/fcntl.h
+++ b/libs/libc/include/fcntl.h
@@ -1,8 +1,11 @@
 #ifndef _FCNTL_H
 #define _FCNTL_H
 
+/* Open for reading only. */
 #define O_RDONLY 1
+/* Open for writing only. */
 #define O_WRONLY 2
+/* Open for reading and writing. */
 #define O_RDWR 3
 
 #ifdef __cplusplus
@@ -10,7 +13,8 @@ extern "C"
 {
 #endif
 
-    int open(const char*, int);
+    /* Opens the file specified by pathname. Returns a file descriptor on success, or -1 on error. */
+    int open(const char* pathname, int flags);
 
 #ifdef __cplusplus
 }