#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

static char *fname;

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 void

do_prepare (void)

{

  static const char pattern[] = "12345678901234567890";

  int fd = create_temp_file ("bug-fseek.", &fname);

  if (fd == -1)

    {

      printf ("cannot create temporary file: %m\n");

      exit (1);

    }

  if (write (fd, pattern, sizeof (pattern)) != sizeof (pattern))

    {

      perror ("short write");

      abort ();

    }

  close (fd);

}

static int

do_test (void)

{

  FILE *f;

  int result = 0;

  char buf[10];

  if ((f = fopen (fname, "r")) == (FILE *) NULL)

    {

      perror ("fopen(\"r\")");

    }

  fread (buf, 3, 1, f);

  errno = 0;

  if (fseek (f, -10, SEEK_CUR) == 0)

    {

      printf ("fseek() for r to before start of file worked!\n");

      result = 1;

    }

  else if (errno != EINVAL)

    {

      printf ("\

fseek() for r to before start of file did not set errno to EINVAL.  \

Got %d instead\n",

	 errno);

      result = 1;

    }

  fclose (f);

  if ((f = fopen (fname, "r+")) == (FILE *) NULL)

    {

      perror ("fopen(\"r+\")");

    }

  fread (buf, 3, 1, f);

  errno = 0;

  if (fseek (f, -10, SEEK_CUR) == 0)

    {

      printf ("fseek() for r+ to before start of file worked!\n");

      result = 1;

    }

  else if (errno != EINVAL)

    {

      printf ("\

fseek() for r+ to before start of file did not set errno to EINVAL.  \

Got %d instead\n",

	 errno);

      result = 1;

    }

  fclose (f);

  if ((f = fopen (fname, "r+")) == (FILE *) NULL)

    {

      perror ("fopen(\"r+\")");

    }

  fread (buf, 3, 1, f);

  if (ftell (f) != 3)

    {

      puts ("ftell failed");

      return 1;

    }

  errno = 0;

  if (fseek (f, -10, SEEK_CUR) == 0)

    {

      printf ("fseek() for r+ to before start of file worked!\n");

      result = 1;

    }

  else if (errno != EINVAL)

    {

      printf ("\

fseek() for r+ to before start of file did not set errno to EINVAL.  \

Got %d instead\n",

	 errno);

      result = 1;

    }

  fclose (f);

  return result;

}