_IO_ssize_t count = _IO_write (f->_fileno, data, to_do);
_IO_ssize_t count = write (f->_fileno, data, to_do);
_IO_file_write (f, data, n)     _IO_FILE *f;     const void *data;     _IO_ssize_t n;{  _IO_ssize_t to_do = n;  while (to_do > 0)    {      _IO_ssize_t count = _IO_write (f->_fileno, data, to_do);      if (count == EOF)	{	  f->_flags |= _IO_ERR_SEEN;	  break;        }      to_do -= count;      data = (void *) ((char *) data + count);    }  n -= to_do;  if (f->_offset >= 0)    f->_offset += n;  return n;}