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-rw-r--r--sysdeps/posix/stdio_init.c70
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diff --git a/sysdeps/posix/stdio_init.c b/sysdeps/posix/stdio_init.c
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+/* Copyright (C) 1991, 1992, 1993, 1995 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 <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/* Initialize STREAM as necessary.
+   This may change I/O functions, give a buffer, etc.
+   If no buffer is allocated, but the bufsize is set,
+   the bufsize will be used to allocate the buffer.  */
+void
+DEFUN(__stdio_init_stream, (stream), FILE *stream)
+{
+  register CONST int fd = (int) stream->__cookie;
+  struct stat statb;
+
+  if (stream->__buffer != NULL || stream->__userbuf)
+    /* If's unbuffered by request, we can't do anything useful.  */
+    return;
+
+  /* Find out what sort of file this is.  */
+  if (__fstat (fd, &statb) < 0)
+      return;
+
+  if (S_ISCHR (statb.st_mode))
+    {
+      /* It's a character device.
+	 Make it line-buffered if it's a terminal.  */
+      if (__isatty (fd))
+	{
+	  stream->__linebuf = 1;
+
+	  /* Unix terminal devices have the bad habit of claiming to be
+	     seekable.  On systems I have tried, seeking on a terminal
+	     device seems to set its file position as specified, such that
+	     a later tell says the same thing.  This is in no way related
+	     to actual seekability--the ability to seek back and read old
+	     data.  Unix terminal devices will let you "seek back", and
+	     then read more new data from the terminal.  I can think of
+	     nothing to do about this lossage except to preemptively disable
+	     seeking on terminal devices.  */
+
+	  stream->__io_funcs.__seek = NULL; /* Seeks get ESPIPE.  */
+	}
+    }
+  
+#ifdef	_STATBUF_ST_BLKSIZE
+  /* Use the block-size field to determine
+     the system's optimal buffering size.  */
+  stream->__bufsize = statb.st_blksize;
+#endif
+}