Update.

2002-07-15  Ulrich Drepper  <drepper@redhat.com>

	* libio/wfileops.c (_IO_wfile_seekoff): Reposition wide pointers
	and adjust state for seek position.  [PR libc/4070]
	* libio/Makefile (tests): Add bug-rewind.
	* libio/bug-rewind.c: New file.

libio/Makefile

@@ -50,7 +50,7 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc   \
 	tst_wprintf2 tst-widetext test-fmemopen tst-ext tst-fopenloc	      \
 	tst-fgetws tst-ungetwc1 tst-ungetwc2 tst-swscanf tst-sscanf	      \
 	tst-mmap-setvbuf bug-ungetwc1 bug-ungetwc2 tst-atime tst-eof          \
-	tst-freopen
+	tst-freopen bug-rewind
 test-srcs = test-freopen
 
 all: # Make this the default target; it will be defined in Rules.

libio/bug-rewind.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <wchar.h>
+
+#define PASSED  0
+#define	FAILED  3
+
+
+int
+main (void)
+{
+  FILE *fptr;
+  char arg1;
+  char arg2;
+  int ret, ret1, ret2, result, num;
+
+  ret1 = 0;
+  ret2 = 0;
+
+  if ((fptr = fopen ("./wrewind.dat", "w+")) == NULL)
+    {
+      printf ("Unable to open file.\n");
+      return 1;
+    }
+
+  if ((ret = fwprintf (fptr, L"cderf")) <= 0)
+    {
+      printf ("Unable to write to file with fwprintf().\n");
+      fclose (fptr);
+      return 2;
+    }
+
+  rewind (fptr);
+  ret1 = fwscanf (fptr, L"%c%c", &arg1, &arg2);
+
+  rewind (fptr);
+  ret2 = fwscanf (fptr, L"%c%n%c", &arg1, &num, &arg2);
+
+  if (arg2 != 'd')
+    {
+      result = FAILED;
+      printf ("rewind after first fwscanf failed\n");
+    }
+  else
+    {
+      printf ("Passed\n");
+      result = PASSED;
+    }
+
+
+  fclose (fptr);
+  return result;
+}

libio/wfileops.c

@@ -635,6 +635,10 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
 #endif
 	  if (rel_offset <= fp->_IO_read_end - fp->_IO_read_base)
 	    {
+	      enum __codecvt_result status;
+	      struct _IO_codecvt *cd = fp->_codecvt;
+	      const char *read_ptr_copy;
+
 	      fp->_IO_read_ptr = fp->_IO_read_base + rel_offset;
 	      _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
 
@@ -643,11 +647,33 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
                  pointer is somewhere in the current external buffer
                  this does not mean we can convert this whole buffer
                  at once fitting in the internal buffer.  */
+	      fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
+	      read_ptr_copy = fp->_IO_read_base;
+	      fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_read_base;
 	      do
 		{
-
+		  wchar_t buffer[1024];
+		  wchar_t *ignore;
+		  status = (*cd->__codecvt_do_in) (cd,
+						   &fp->_wide_data->_IO_state,
+						   read_ptr_copy,
+						   fp->_IO_read_ptr,
+						   &read_ptr_copy,
+						   buffer,
+						   buffer
+						   + (sizeof (buffer)
+						      / sizeof (buffer[0])),
+						   &ignore);
+		  if (status !=  __codecvt_ok && status != __codecvt_partial)
+		    {
+		      fp->_flags |= _IO_ERR_SEEN;
+		      goto dumb;
+		    }
 		}
-	      while (0);
+	      while (read_ptr_copy != fp->_IO_read_ptr);
+
+	      fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_read_end
+		= fp->_wide_data->_IO_read_base;
 
 	      _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
 	      goto resync;