On 11/11/10 8:55 AM, "me22" <me22.ca@xxxxxxxxx> wrote: > On Thu, Nov 11, 2010 at 03:03, Jan M <jan_m@xxxxxxxxxxxxxxxx> wrote: >> >> I cannot make operator new fail to check this (even allocating a terabyte >> succeeds) . >> > > Do you have overcommit memory on? It's possible that the kernel is > letting it succeed. > > <http://opsmonkey.blogspot.com/2007/01/linux-memory-overcommit.html> I'm more of a sysadmin than a software engineer (hey, nobody's perfect) but have lost count of the number of times a software engineer would get tunnel vision and not check the amount of system memory or free memory before allocating, then try to use and crash. Most of the newer Linux kernels have overcommit turned on because of the ability to swap and all that, will cheerfully allow you to new[] as much memory as you want and I've even seen instance wheres malloc and memset have succeeded even when there's not enough physical memory to go around. It's pretty easy to check the total memory, free memory and swap before new'ing anything :-) -b
