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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/freopen.c
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initial import
Diffstat (limited to 'stdio/freopen.c')
-rw-r--r--stdio/freopen.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/stdio/freopen.c b/stdio/freopen.c
new file mode 100644
index 0000000000..bedddb1a63
--- /dev/null
+++ b/stdio/freopen.c
@@ -0,0 +1,74 @@
+/* Copyright (C) 1991, 1994, 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 <errno.h>
+#include <stdio.h>
+
+
+/* Defined in fopen.c.  */
+extern int __getmode __P ((const char *, __io_mode *));
+
+/* Defined in sysd-stdio.c.  */
+extern int __stdio_reopen __P ((const char *filename, __io_mode mode,
+				PTR *cookieptr, __io_close_fn closefn));
+
+/* Replace STREAM, opening it on FILENAME.  */
+FILE *
+DEFUN(freopen, (filename, mode, stream),
+      CONST char *filename AND CONST char *mode AND register FILE *stream)
+{
+  __io_mode m;
+  PTR cookie;
+
+  if (!__getmode (mode, &m))
+    {
+      (void) fclose (stream);
+      errno = EINVAL;
+      return NULL;
+    }
+
+  if (stream->__mode.__write)
+    /* Flush the stream.  */
+    (void) fflush (stream);
+
+  /* Open the file, attempting to preserve the old cookie value.  */
+  cookie = stream->__cookie;
+  if (__stdio_reopen (filename, m, &cookie,
+		      stream->__seen ?
+		      stream->__io_funcs.__close :
+		      __stdio_close))
+    {
+      int save = errno;
+      (void) fclose (stream);
+      errno = save;
+      return NULL;
+    }
+
+  /* Close the stream, first disabling its cookie close function because
+     __stdio_reopen has already dealt with closing the old cookie.  */
+  stream->__seen = 1;		/* It might have no functions yet.  */
+  stream->__io_funcs.__close = NULL;
+  (void) fclose (stream);
+
+  stream->__magic = _IOMAGIC;
+  stream->__cookie = cookie;
+  stream->__mode = m;
+
+  return stream;
+}