sub MyFunc {
    my $arrRef= shift(@_);
    my $packedArr= pack("f*",@$arrRef);
    return MyFuncC( 0+@$arrRef, $packedArr );
}

##</code><code>##

int MyFuncC( count, packedArray )
        int    count;
        char * packedArray;
    CODE:
        RETVAL= CFunc( count, (float *)packedArray );