#define PERLIO_MAX_REFCOUNTABLE_FD 2048

##</code><code>##

PerlIO *
PerlIOUnix_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
{
    PerlIOUnix *os = PerlIOSelf(o, PerlIOUnix);
    int fd = os->fd;
    if (flags & PERLIO_DUP_FD) {
        fd = PerlLIO_dup(fd);
    }
    if (fd >= 0 && fd < PERLIO_MAX_REFCOUNTABLE_FD) {
        f = PerlIOBase_dup(aTHX_ f, o, param, flags);
        if (f) {
            /* If all went well overwrite fd in dup'ed lay with the dup()'ed fd */
            PerlIOUnix_setfd(aTHX_ f, fd, os->oflags);
            return f;
        }
    }
    return NULL;
}