REGEXP Functions

Convenience macro to get the REGEXP from a SV. This is approximately equivalent to the following snippet:

if (SvMAGICAL(sv))
    mg_get(sv);
if (SvROK(sv) &&
    (tmpsv = (SV*)SvRV(sv)) &&
    SvTYPE(tmpsv) == SVt_PVMG &&
    (tmpmg = mg_find(tmpsv, PERL_MAGIC_qr)))
{
    return (REGEXP *)tmpmg->mg_obj;
}

NULL will be returned if a REGEXP* is not found.

Returns a boolean indicating whether the SV contains qr magic (PERL_MAGIC_qr).

If you want to do something with the REGEXP* later use SvRX instead and check for NULL.