/*
 *  call-seq:
 *     struct.length    => fixnum
 *     struct.size      => fixnum
 *  
 *  Returns the number of instance variables.
 *     
 *     Customer = Struct.new(:name, :address, :zip)
 *     joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
 *     joe.length   #=> 3
 */

static VALUE
rb_struct_size(VALUE s)
{
    return LONG2FIX(RSTRUCT_LEN(s));
}