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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /stdio/setvbuf.c
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initial import
Diffstat (limited to 'stdio/setvbuf.c')
-rw-r--r--stdio/setvbuf.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/stdio/setvbuf.c b/stdio/setvbuf.c
new file mode 100644
index 0000000000..8c33386610
--- /dev/null
+++ b/stdio/setvbuf.c
@@ -0,0 +1,85 @@
+/* Copyright (C) 1991, 1993 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+
+/* Make STREAM use the buffering method given in MODE.
+   If MODE indicates full or line buffering, use BUF,
+   a buffer of SIZE bytes; if BUF is NULL, malloc a buffer.  */
+int
+DEFUN(setvbuf, (stream, buf, mode, size),
+      FILE *stream AND char *buf AND int mode AND size_t size)
+{
+  if (!__validfp(stream))
+    {
+      errno = EINVAL;
+      return EOF;
+    }
+
+  /* The ANSI standard says setvbuf can only be called before any I/O is done,
+     but we allow it to replace an old buffer, flushing it first.  */
+  if (stream->__buffer != NULL)
+    {
+      (void) fflush(stream);
+      /* Free the old buffer if it was malloc'd.  */
+      if (!stream->__userbuf)
+	free(stream->__buffer);
+    }
+
+  stream->__get_limit = stream->__put_limit = NULL;
+  stream->__bufp = stream->__buffer = NULL;
+  stream->__userbuf = stream->__linebuf = stream->__linebuf_active = 0;
+
+  switch (mode)
+    {
+    default:
+      errno = EINVAL;
+      return EOF;
+    case _IONBF:	/* Unbuffered.  */
+      stream->__buffer = NULL;
+      stream->__bufsize = 0;
+      stream->__userbuf = 1;
+      break;
+    case _IOLBF:	/* Line buffered.  */
+      stream->__linebuf = 1;
+    case _IOFBF:	/* Fully buffered.  */
+      if (size == 0)
+	{
+	  errno = EINVAL;
+	  return EOF;
+	}
+      stream->__bufsize = size;
+      if (buf != NULL)
+	stream->__userbuf = 1;
+      else if ((buf = (char *) malloc(size)) == NULL)
+	return EOF;
+      stream->__buffer = buf;
+      break;
+    }
+
+  stream->__bufp = stream->__buffer;
+  stream->__get_limit = stream->__buffer;
+  /* The next output operation will prime the stream for writing.  */
+  stream->__put_limit = stream->__buffer;
+
+  return 0;
+}