David Brown wrote: > On Mon, Jan 07, 2008 at 02:59:52AM -0800, Andrew Lentvorski wrote: > >> It is considered bad style in C++ because of the semantics of stack >> allocation. >> >> Declaring everything at the top of a function means that everything >> gets allocated on the stack immediately upon function entry and is >> held until function exit. > > I doubt you could find a compiler still around that would perform this > basic of an optimization. I'm not even sure you would ever find a > compiler > that accepted mixed-declarations and allocated by default on exit. The > only time you need to delay the allocation is when the size isn't known > until the declaration (such as an array dimension). In this case, it > wouldn't be possible to move the declaration to the top anyway. I think Andrew was probably referring to initialization (which can be insanely expensive) more than allocation, but even in the case of allocation it can end up making a not insignificant difference.
--Chris -- KPLUG-LPSG@kernel-panic.org http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-lpsg
