_IO_fileno
if (!(fp->_flags & _IO_IS_FILEBUF) || _IO_fileno (fp) < 0)
return _IO_fileno (fp);
int fd = _IO_fileno (fp);
__dup3 (_IO_fileno (result), fd,
__dup2 (_IO_fileno (result), fd);
__close (_IO_fileno (result));
_IO_fileno (result) = fd;
int fd = _IO_fileno (fp);
int fd = _IO_fileno ((_IO_FILE *) p);
_IO_fileno (fp) = parent_end;
if (status < 0 || _IO_close (_IO_fileno(fp)) < 0)