Initial import

libc/stdio/setvbuf.c

@@ -0,0 +1,38 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/bits.h"
+#include "libc/stdio/stdio.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Tunes buffering settings for an stdio stream.
+ *
+ * @param mode may be _IOFBF, _IOLBF, or _IONBF
+ * @param buf may optionally be non-NULL to set the stream's underlying
+ *     buffer, which the stream will own, but won't free
+ * @param size must be a two power if buf is provided
+ * @return 0 on success or -1 on error
+ */
+int setvbuf(FILE *f, char *buf, int mode, size_t size) {
+  if (size && popcount(size) != 1) return einval();
+  setbuffer(f, buf, size);
+  f->bufmode = mode;
+  return 0;
+}