Is it possible to get pointer to hash value?

[Oleg Yu. Tokarev]

An xs-function has a reference to a hash as its input, like this:
my $h = {KEY => 123, VAL => 0};
bla::bla( $h );
The xs-function updates $h->{VAL} during its execution.
Inside itself the xs-function call a C-library function.
Its prototype is: int cbla (int key, int *val);
The question:
Can i get a pointer to int-value saved in the hash?
Or in other words: I can get SV saved in the hash. Can i get a pointer 
to a memory slot in the SV where 'int' saved?

'&(SvIV(something))' does not work!

May be there is another way to resolve a such problem, is there?

Oleg T

PS:

Sample code:

#
# Function: cx_getvalue(conn, rec)
# Description:
# 'conn' is an output from cx_connect;
# 'rec' is a hash like this:
# $rec = {CHAN => $chan, VALUE => $value, TAG => $tag};
#
# after execution of the function, $rec{CHAN} will remain unchanged,
# $rec{VALUE} will contain value from channel $chan, $rec{TAG} will
# contain a 'freshness' tag;
#
int
cx_dummy (conn, rec)
        int conn
        SV * rec
INIT:
        SV * rec_tag_name;
        SV * rec_value_name;
        SV * rec_chan_name;
        
        SV *  rec_value_val;
        SV *  rec_tag_val;
        SV *  rec_chan_val;
        HE * he;
        RETVAL = 0;
# Create SV* for the rec hash keys for a comfortable use in hv_*_ent.   
        rec_tag_name = sv_2mortal(newSVpv(CX_REC_TAG_NAME, 0));
        rec_value_name = sv_2mortal(newSVpv(CX_REC_VALUE_NAME, 0));
        rec_chan_name = sv_2mortal(newSVpv(CX_REC_CHAN_NAME, 0));
    
# Check if 'rec' has keys 'CHAN', 'TAG'. If it hasn't, we must create them.
# If there is not 'CHAN' key, we must give up with error.
        
        if ((!SvROK(rec))
        || (SvTYPE(SvRV(rec)) != SVt_PVHV)
        || (NULL == (he =
                                hv_fetch_ent((HV *)SvRV(rec), rec_chan_name, 0, 0)))
        ){
                croak("Check if a second parameter is defined properly!!!");
        } else {
                rec_chan_val = HeVAL(he);
                printf("%p\n", );
        }
# allocate memory for others keys if it hasn't allocated yet.
        if (!hv_exists_ent((HV *)SvRV(rec), rec_value_name, 0)){
                rec_value_val = newSViv(2);
                if (NULL == hv_store_ent((HV *)SvRV(rec), rec_value_name,
                                                                 rec_value_val, 0)){
                        SvREFCNT_dec(rec_value_val);
                        warn("hv_store_ent: failed!!!");
                        RETVAL = -1;
                }
        }
        if (!hv_exists_ent((HV *)SvRV(rec), rec_tag_name, 0)){
                rec_tag_val = newSViv(3);
                if (NULL == hv_store_ent((HV *)SvRV(rec),
                                                                 rec_tag_name,
                                                                 rec_tag_val,
                                                                 0)){
                        SvREFCNT_dec(rec_tag_val);
                        warn("hv_store_ent: failed!!!");
                        RETVAL = -1;
                }
        }
        printf("%d %d %d\n",
                   SvIV(rec_chan_val),
                   SvIV(rec_value_val),
                   SvIV(rec_tag_val));
CODE:
        if (RETVAL == 0){
        }
OUTPUT:
        RETVAL