eql?

static VALUE
proc_eq(VALUE self, VALUE other)
{
    if (self == other) {
        return Qtrue;
    }
    else {
        if (TYPE(other)          == T_DATA &&
            RDATA(other)->dmark  == proc_mark) {
            rb_proc_t *p1, *p2;
            GetProcPtr(self, p1);
            GetProcPtr(other, p2);
            if (p1->envval == p2->envval &&
                p1->block.iseq->iseq_size == p2->block.iseq->iseq_size &&
                p1->block.iseq->local_size == p2->block.iseq->local_size &&
                MEMCMP(p1->block.iseq->iseq, p2->block.iseq->iseq, VALUE,
                       p1->block.iseq->iseq_size) == 0) {
                return Qtrue;
            }
        }
    }
    return Qfalse;
}