diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index ce60fd7..594d231 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -66,10 +66,17 @@
  */
 
 /* stdio buffers */
+#if defined(__LP64__)
+struct __sbuf {
+  unsigned char* _base;
+  size_t _size;
+};
+#else
 struct __sbuf {
 	unsigned char *_base;
 	int	_size;
 };
+#endif
 
 /*
  * stdio state variables.
@@ -102,8 +109,13 @@
 	unsigned char *_p;	/* current position in (some) buffer */
 	int	_r;		/* read space left for getc() */
 	int	_w;		/* write space left for putc() */
+#if defined(__LP64__)
+	int	_flags;		/* flags, below; this FILE is free if 0 */
+	int	_file;		/* fileno, if Unix descriptor, else -1 */
+#else
 	short	_flags;		/* flags, below; this FILE is free if 0 */
 	short	_file;		/* fileno, if Unix descriptor, else -1 */
+#endif
 	struct	__sbuf _bf;	/* the buffer (at least 1 byte, if !NULL) */
 	int	_lbfsize;	/* 0 or -_bf._size, for inline putc */