#! perl -slw
use strict;
use Inline C => Config => BUILD_NOISY => 1;
use Inline C => <<'END_C',  NAME => 'test', CLEAN_AFTER_BUILD => 0;

char *newxz( unsigned __int64 bytes ) {
    char *p;
    warn( "Attempting allocate %I64u bytes\n", bytes );
    Newxz( p, bytes, char );
    if( !p ) croak( "Couldn't allocate %I64u bytes\n", bytes );
    return p;
}

SV* new( const char * classname, SV *bits ) {
    unsigned __int64 bytes = ( SvUV( bits )+7 ) / 8;
    unsigned char *vector = newxz( bytes );
    SV      * obj;
    SV      * obj_ref;

    obj = newSV( 0 );
    SvPOK_only( obj );
    SvPV_set( obj, vector );
    SvLEN_set( obj, bytes );
    obj_ref = newRV_noinc( obj );
    sv_bless( obj_ref, gv_stashpv( classname, GV_ADD) );

    return obj_ref;
}

END_C

use Devel::Peek;

my $v = new( 'fred', eval $ARGV[ 0 ] );
#print length $$v;
Dump( $$v );