The Importance Of Locality
Since I love the programming language he created and I’m a fan of his personal philosophy, I’m always on the lookout for interviews of Bjarne Stroustrup. As far as I can tell, the most recent one is captured here: “An Interview with Bjarne Stroustrup | | InformIT“. Of course, since the new C++11 version of his classic TC++PL book is now available, the interview focuses on the major benefits of the new set of C++11 language features.
For your viewing pleasure and retention in my archives, I’ve clipped some juicy tidbits from the interview and placed them here:
Adding move semantics is a game changer for resource (memory, locks, file handles, threads, and sockets) management. It completes what was started with constructor/destructor pairs. The importance of move semantics is that we can basically eliminate complicated and error-prone explicit use of pointers and new/delete in most code.
TC++PL4 is not simply a list of features. I try hard to show how to use the new features in combination. C++11 is a synthesis that supports more elegant and efficient programming styles.
I do not consider it the job of a programming language to be “secure.” Security is a systems property and a language that is – among other things – a systems programming language cannot provide that by itself.
The repeated failures of languages that did promise security (e.g. Java), demonstrates that C++’s more modest promises are reasonable. Trying to address security problems by having every programmer in every language insert the right run-times checks in the code is expensive and doomed to failure.
Basically, C is not the best subset of C++ to learn first. The “C first” approach forces students to focus on workarounds to compensate for weaknesses and a basic level of language that is too low for much programming.
Every powerful new feature will be overused until programmers settle on a set of effective techniques and find which uses impede maintenance and performance.
I consider Garbage Collection (GC) the last alternative after cleaner, more general, and better localized alternatives to resource management have been exhausted. GC is fundamentally a global memory management scheme. Clever implementations can compensate, but some of us remember too well when 63 processors of a top-end machine were idle when 1 processor cleaned up the garbage for them all. With clusters, multi-cores, NUMA memories, and multi-level caches, systems are getting more distributed and locality is more important than ever.