Test for ungetc bug.

libio/bug-ungetc4.c

@@ -0,0 +1,116 @@
+/* Test program for ungetc/fseekpos interaction.
+   Copyright (C) 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Jakub Jelinek <jakub@redhat.com>, 2004.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <stdio.h>
+
+static void do_prepare (void);
+#define PREPARE(argc, argv) do_prepare ()
+static int do_test (void);
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
+
+static const char pattern[] = "abcdefghijklmnopqrstuvwxyz";
+static char *temp_file;
+
+static void
+do_prepare (void)
+{
+  int fd = create_temp_file ("bug-ungetc.", &temp_file);
+  if (fd == -1)
+    {
+      printf ("cannot create temporary file: %m\n");
+      exit (1);
+    }
+  write (fd, pattern, sizeof (pattern) - 1);
+  close (fd);
+}
+
+#define TEST_POS 5
+
+static int
+do_one_test (int mode)
+{
+  FILE *f = fopen (temp_file, "r");
+  if (f == NULL)
+    {
+      printf ("%d: could not open temporary file: %m\n", mode);
+      return 1;
+    }
+
+  int i;
+  for (i = 0; i < TEST_POS; ++i)
+    getc (f);
+
+  fpos_t p;
+  if (fgetpos (f, &p) != 0)
+    {
+      printf ("%d: fgetpos failed: %m\n", mode);
+      return 1;
+    }
+
+  if (mode)
+    {
+      if (fseek (f, 0, SEEK_SET) != 0)
+        {
+          printf ("%d: fseek failed: %m\n", mode);
+          return 1;
+        }
+
+      for (i = 0; i < TEST_POS - (mode >= 2); ++i)
+        getc (f);
+    }
+
+  if (mode != 2 && ungetc ('X', f) != 'X')
+    {
+      printf ("%d: ungetc failed\n", mode);
+      return 1;
+    }
+
+  if (mode == 3 && getc (f) != 'X')
+    {
+      printf ("%d: getc after ungetc did not return X\n", mode);
+      return 1;
+    }
+
+  if (fsetpos (f, &p) != 0)
+    {
+      printf ("%d: fsetpos failed: %m\n", mode);
+      return 1;
+    }
+
+  if (getc (f) != pattern[TEST_POS])
+    {
+      printf ("%d: getc did not return %c\n", mode, pattern[TEST_POS]);
+      return 1;
+    }
+
+  fclose (f);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  int mode, ret = 0;
+  for (mode = 0; mode <= 4; mode++)
+    ret |= do_one_test (mode);
+  return ret;
+}