auto import from //depot/cupcake/@135843
diff --git a/libc/stdio/fflush.c b/libc/stdio/fflush.c
new file mode 100644
index 0000000..3f72ad8
--- /dev/null
+++ b/libc/stdio/fflush.c
@@ -0,0 +1,82 @@
+/* $OpenBSD: fflush.c,v 1.5 2005/08/08 08:05:36 espie Exp $ */
+/*-
+ * Copyright (c) 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include "local.h"
+
+/* Flush a single file, or (if fp is NULL) all files. */
+int
+fflush(FILE *fp)
+{
+
+ if (fp == NULL)
+ return (_fwalk(__sflush));
+ if ((fp->_flags & (__SWR | __SRW)) == 0) {
+ errno = EBADF;
+ return (EOF);
+ }
+ return (__sflush(fp));
+}
+
+int
+__sflush(FILE *fp)
+{
+ unsigned char *p;
+ int n, t;
+
+ t = fp->_flags;
+ if ((t & __SWR) == 0)
+ return (0);
+
+ if ((p = fp->_bf._base) == NULL)
+ return (0);
+
+ n = fp->_p - p; /* write this much */
+
+ /*
+ * Set these immediately to avoid problems with longjmp and to allow
+ * exchange buffering (via setvbuf) in user write function.
+ */
+ fp->_p = p;
+ fp->_w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
+
+ for (; n > 0; n -= t, p += t) {
+ t = (*fp->_write)(fp->_cookie, (char *)p, n);
+ if (t <= 0) {
+ fp->_flags |= __SERR;
+ return (EOF);
+ }
+ }
+ return (0);
+}