[boost] Re: Boost.Threads: Do we need all those mutexes?

From: Howard Hinnant (hinnant_at_[hidden])
Date: 2004-07-05 21:55:52

On Jul 5, 2004, at 10:35 PM, Howard Hinnant wrote:

> vs this:
>
> void do_sale(rw_mutex& m)
> {
>   read_lock rl(m);
>
>   long balance = get_balance();
>   long cost = get_total_cost();
>
>   if (balance > cost)
>   {
>     rl.unlock(m);
>     write_lock wl(m);
>     set_balance(balance - cost);
>     wl.transfer_to_read_lock(rl);
>     balance = get_balance();
>   }
>   // ...
> }

Oops, that should be:

vs this:

void do_sale(rw_mutex& m)
{
   read_lock rl(m);

   long balance = get_balance();
   long cost = get_total_cost();

   if (balance > cost)
   {
     rl.unlock(m);
     write_lock wl(m);
     cost = get_total_cost();
     set_balance(get_balance() - cost);
     wl.transfer_to_read_lock(rl);
     balance = get_balance();
   }
   // ...
}

but still looks much simpler, and smaller code size to me.

-Howard