On Jan 9, 2006, at 10:13 AM, Peter Dimov wrote:
Douglas Gregor wrote:
On Jan 9, 2006, at 7:18 AM, Peter Dimov wrote:
Even if I did, bind(&X::f, &x, _1, true) would still overflow the 12 byte buffer. ;-)
Why? Does it need more than the 8-byte member pointer and 4-byte pointer?
The 'true' needs to be stored somewhere.
*Smacks forehead* I didn't see the true, because I was assuming that you had written bind(&X::f, &x, _1) :) Anyway, we're going to have a cutoff somewhere, The curse of the SBO is that at some point your objects don't fit into the small buffer any more, so you have a jump in your performance curve. If we go to 16 bytes, then bind(&X::f, &x, _1, true) will fit but bind(&X::f, &x, _1, true, true) won't. The member pointer + "this" pointer case seems like the one that users would most expect to work well. It goes head- to-head with delegates, closures, and other similar extensions, with the added benefit of keeping boost::function down to 16 bytes. It just feels like the right cutoff for the buffer size. Doug