I don’t think that casting a range of bits as some other arbitrary type “is a bug nobody sees coming”.
C++ compilers also warn you that this is likely an issue and will fail to compile if configured to do so. But it will let you do it if you really want to.
That’s why I love C++
I want you to imagine that your comments in this thread were written by an engineer or a surgeon instead of a programmer.
Imagine an engineer saying “Sure, you can calculate the strength of a bridge design based on known material properties and prove that it can hold the design weight, it that doesn’t automatically mean that the design will be safer than one where you don’t do that”. Or “why should I have to prove that my design is safe when the materials could be defective and cause a collapse anyway?”
Or a surgeon saying “just because you can use a checklist to prove that all your tools are accounted for and you didn’t leave anything inside the patient’s body doesn’t mean that you’re going to automatically leave something in there if you don’t have a checklist”. Or “washing your hands isn’t a guarantee that the patient isn’t going to get an infection, they could get infected some other way too”.
A doctor or engineer acting like this would get them fired, sued, and maybe even criminally prosecuted, in that order. This is not the mentality of a professional, and it is something that programming as a profession needs to grow out of.
Every single doctor should know this yes.
It seems people are adding a sentence I didn’t say “rust can be unsafe and thus we shouldn’t try” on top of the one I did say “programmers should be aware that rust doesn’t automatically mean safe”.
You didn’t say “programmers should be aware that rust doesn’t automatically mean safe”. You said:
You then went on to mention
unsafe, conflating “security” and “safety”; Rust’s guarantees are around safety, not security, so it sounds like you really mean “more safe” here. But Rust does make software more safe than C++: it prohibits memory safety issues that are permitted by C++.You then acknowledged:
…which seems to be the opposite of your original statement that Rust doesn’t make software “more secure”. But in the same comment:
…well, no, there IS a guarantee that Rust is “automatically” (memory) safe, and to violate that safety, your program must either explicitly opt out of that “automatic” guarantee (using
unsafe) or exploit (intentionally or not) a compiler bug.This is also true! “Safety” is a property of proofs: it means that a specific undesirable thing cannot happen. The C++ compiler doesn’t provide safety properties[1]. The opposite of “safety” is “liveness”, meaning that some desirable thing does happen, and C++ does arguably provide certain liveness properties, in particular RAII, which guarantees that destructors will be called when leaving a call-stack frame.
[1] This is probably over-broad, but I can’t think of any safety properties C++ the language does provide. You can enfor your own safety properties in library code, and the standard library provides some; for instance, mutexes have safety guarantees.
Then you should probably be a little more explicit about that, because I have never, not once in my life, heard someone say “well you know wearing a seatbelt doesn’t guarantee you’ll survive a car crash” and not follow it up with “that’s why seatbelts are stupid and I’m not going to wear one”.
We need to stop attaching shit someone doesn’t say to something they did. It makes commutating hostile and makes you an asshole.
Edit: okay that was a bit rude. But it’s so frustrating to say something and then have other people go “that means <this other thing you didn’t say>!!!11!”
I understand your frustration and I apologize for reading into your comments something you didn’t mean. I, too, wish people would say what they mean and mean what they say, and that when you say something its taken to mean what you said.
Unfortunately very often people will make a very reasonable (even factually true) point as a preamble to support something very unreasonable. If you agree with the reasonable point the person will then act like you agree with the unreasonable one. This is not only more time consuming and tiring to argue against, it also lends a great deal more credibility to the unreasonable point than it is really owed. To the uninformed reader to looks like the two sides of the argument partially agree, when nothing could be further from the truth. Its immensely frustrating to have your words used against you like this, so many people try and preempt it by jumping straight to (what they assume to be) the unreasonable point and arguing against it directly.
This is toxic for actual discussion. It means that good faith actors have to add all sorts of qualifications and clarifications about where they stand before they say anything about anything, which is tiring in itself. But its the world that we live in. If someone makes an unqualified comment about the CO2 emissions of volcanoes in a thread about anthropogenic climate change people are going to assume that they don’t think climate change is real. And, operating that way, those people will be right more often than they’re wrong.