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0 pointsesrauch7y ago0 comments

When I worked on a mobile C++ project at Google, we went exceptionally out of our way to avoid memory issues.

We ran under valgrind and multiple sanitizers (and continuously ran those with high coverage unit and integration tests). We ran fuzzers. We had strictly enforced style guides.

We still shipped multiple use after frees and ub-tripping behavior. I also saw multiple issues in other major libraries that we were building from source so it can't be pointed at as just incompetency on my team.

Basically, it might be possible but I think it's exceptionally more difficult to write memory safe C++ than this thread is making it sound.

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gmueckl7y ago

Writing memory safe programs in C++ is possible. Most coding styles and some problem domains don't lend themselves to it naturally, though. In my experience, restricted subsets used for embedded software vastly reduce the risk of introducing errors and make actual errors easier to spot and fix.

sgift7y ago

> Writing memory safe programs in C++ is possible.

Everything "is possible" in the sense that in theory you can do it. But if time and time again people fail to do it. Even people who invest almost heroic levels of effort (see above: valgrind, multiple sanitizers, and so on) you get to the point where you have to accept that what is possible in theory doesn't work in practice.

gmueckl7y ago

I have seen it done in practice, on rather large systems. But it requires actual, slow software engineering instead of the freestyle coding processes that are used in most places.

paulmooreparks7y ago

My main rule is "no naked new," meaning that the only place the new operator is allowed is in a constructor, and the only place delete is allowed is in a destructor (unless there's some very special circumstance). This style lends itself to RAII. The other rule is to use the standard library containers unless there's a very good reason not to do so. That seems to cover most of the really basic errors.

ncmncm7y ago

Yes, I know how you code are obliged to code at Google. It is astonishing that anything works.

The "strictly enforced style guides" strictly enforce '90s coding habits.

j / k navigate · click thread line to collapse

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gmueckl7y ago

sgift7y ago

> Writing memory safe programs in C++ is possible.

gmueckl7y ago

I have seen it done in practice, on rather large systems. But it requires actual, slow software engineering instead of the freestyle coding processes that are used in most places.

paulmooreparks7y ago

ncmncm7y ago

Yes, I know how you code are obliged to code at Google. It is astonishing that anything works.

The "strictly enforced style guides" strictly enforce '90s coding habits.

j / k navigate · click thread line to collapse