diff --git a/include/picrin/port.h b/include/picrin/port.h
index cb326bd1..8c78c707 100644
--- a/include/picrin/port.h
+++ b/include/picrin/port.h
@@ -66,15 +66,11 @@ int pic_setvbuf(pic_file *, char *, int, size_t);
 int pic_fflush(pic_file *);
 int pic_ffill(pic_file *);
 
-/* file access */
+/* resource aquisition */
 pic_file *pic_fopen(const char *, const char *);
+pic_file *pic_mopen(const char *, size_t, const char *);
 int pic_fclose(pic_file *);
 
-/* memory access */
-pic_file *pic_mropen(const char *, size_t, const char *);
-pic_file *pic_mwopen();
-const char *pic_getmbuf(pic_file *);
-
 /* direct IO with buffering */
 size_t pic_fread(void *, size_t, size_t, pic_file *);
 size_t pic_fwrite(const void *, size_t, size_t, pic_file *);