#include <stdio.h>
#include <errno.h>
#include <stdarg.h>
#include <sys/stat.h>
#include <fcntl.h>

void
pfatal (char const *format, ...)
{
  int errnum = errno;
  va_list args;
  fprintf (stderr, "%s: **** ", "tst");
  va_start (args, format);
  vfprintf (stderr, format, args);
  va_end (args);
  fflush (stderr); /* perror bypasses stdio on some hosts.  */
  errno = errnum;
  perror (" ");
  fflush (stderr);
  exit(1);
}

/* Create FILE with OPEN_FLAGS, and with MODE adjusted so that
   we can read and write the file and that the file is not executable.
   Return the file descriptor.  */
int
create_file (char const *file, int open_flags, mode_t mode)
{
  int fd;
  mode |= S_IRUSR | S_IWUSR;
  mode &= ~ (S_IXUSR | S_IXGRP | S_IXOTH);
  if (! (O_CREAT && O_TRUNC))
    close (creat (file, mode));
  fd = open (file, O_CREAT | O_TRUNC | open_flags, mode);
  if (fd < 0)
    pfatal ("Can't create file %s", file);
  return fd;
}


#define HAVE_FSEEKO 1
#ifdef HAVE_FSEEKO
# define file_seek fseeko
  typedef off_t file_offset;
#else
# define file_seek fseek
  typedef long file_offset;
#endif

int 
main (int argc, char **argv)
{
    FILE *pfp;

    pfp = fdopen(create_file ("tst.file",
                              O_RDWR | O_BINARY,
                              (mode_t) 0),
                 "w+b");
    if (!pfp) {
        pfatal("fopen");
    }

    char* buf = "this is a test file\npretty cool, huh?\n";
    size_t bufsize = sizeof(char) * strlen(buf);
    if (fwrite(buf, 1, bufsize, pfp) != bufsize) {
        pfatal("fwrite");
    }
    if (fflush(pfp) != 0) {
        pfatal("pfp");
    }
    if (file_seek(pfp, (file_offset) 0, SEEK_SET) != 0) {
        pfatal("file_seek");
    }

    buf = (char*) malloc(bufsize);
    while (fread(buf, 1, bufsize, pfp) != 0)
        ;

    printf("buf\n---------\n%s", buf);

    exit(0);
}