dooglius

27 ms·

481.
by dooglius 5y ago
I am aware of these things, the rant by Ulrich Drepper on this breaking glibc guarantees [0] explicitly what I had in mind when writing that. [0] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25609
482.
by dooglius 5y ago
Why is it UB to use registers to store variables? This seems like an implementation detail. The ISO C spec doesn't even have the word "stack" as far as ctrl-f can show me.
483.
by dooglius 5y ago
That's fair, I'll concede that I make some implicit assumptions. But the magnitude of people who hit problems and accidentally hit UB should give a strong indication that a lot of things done now are not close to sane.
484.
by dooglius 5y ago
Okay, yes, you are technically right. What I mean is, making an assumption _other than_ that the code won't alter stack/heap/instruction memory that the implementation is using (e.g. aliasing, overflow, use of NULL)
485.
by dooglius 5y ago
I might be using the wrong terminology, what I'm talking about is removing e.g. `int x = *ptr` where x is then not used in scope (more realistically, `(*struct_inst).member` shouldn't bother to load the other members of the struct
486.
by dooglius 5y ago
For [1] I would say that when the compiler does not control the standard library (e.g. most linux systems) then the compiler should treat qsort like any normal non-libc function call, it shouldn't be able to detect that I might be rely
487.
by dooglius 5y ago
> You can cast literally any optimization into this shape Tell me how these use UB: integer constant folding, unused load removal, optimal use of GP registers to minimize stack spilling >sane assumptions "sane" here is doing
488.
by dooglius 5y ago
What "compiler"? We're talking about the x86 instruction specification. The microcode translator certainly isn't allowed make the sort of optimization you're describing, that would be a violation of the spec that GP
489.
by dooglius 5y ago
You are strawmanning the parent, he did not claim that compilers will go "oh, you wrote to this variable without synchronization! Now I'll show you, hehehe!". Your description of the compiler's behavior matches his descr
490.
by dooglius 5y ago
In ring zero there are some, but no instructions that userspace can use (or else security would be impossible)
491.
by dooglius 5y ago
No, this is not the same thing as "undefined behavior" in the sense the ISO C spec defines it. The content of the output being unspecified would not, for example, allow the processor to write to some part of memory if the source i
492.
by dooglius 5y ago
I didn't sign a contract though, the compilers just do dumb things and I am at their mercy. If I were negotiating a contract then I wouldn't allow all the cases of UB.
493.
by dooglius 5y ago
I recall reading recently that gcc moved to making overflow undefined at -O0
494.
by dooglius 5y ago
Do you have a cite for this for SHA256? It surprises me a bit as our galaxy is big and we are far from physically ideal computers.
495.
by dooglius 5y ago
What does "authentic" mean here? Isn't company swag just the company emailing a logo to 3rd parties who print it on shirts/whatever?
496.
by dooglius 5y ago
Is it actually more effective at that? Are people who employ humanities thinking any better at say social engineering than are people with equivalent verbal skills who don't employ humanities thinking?
497.
by dooglius 5y ago
Hardware synchronization has better properties than software locks: it can't deadlock, is reentrant, won't get screwed up by a process holding a lock dying, and is (supposedly) guaranteed to complete in bounded time. I don't
498.
by dooglius 5y ago
See https://xorshammer.com/2009/03/23/what-happens-when-you-iter... basically you have problems once you get past the finite ordinals.
499.
by dooglius 5y ago
> or require any workers who remain unvaccinated to produce a negative test result on at least a weekly basis before coming to work So is this a no-op for people who work from home exclusively? that seems like a pretty major thing to j
500.
by dooglius 5y ago
From what I've read, one of the things the helicopter project did was to see how well ignoring the usual heavy verification would go--it used consumer-grade off-the-shelf hardware as well, for instance.
501.
by dooglius 5y ago
The parent comment was literally suggesting that GP should have allowed the equipment to fail so that IT could be blamed. I didn't get the impression GP's situation was the result of not bothering to sit down and talk to a higher-
502.
by dooglius 5y ago
"What did you accomplish during your time with X research group?" "Nothing since all our equipment broke, but we documented how it was all IT's fault. You shoulda seen the looks on their faces when we called them out on
503.
by dooglius 5y ago
One of the major pillars of measure theory is countable subadditivity, which serves to allow one to work with countably infinite series in a nice way. This is pretty much unworkable in a countable space like the computables. That isn't
504.
by dooglius 5y ago
It's not individual numbers that matter, but the properties of sets of them and functions over them. You can define a Reimann integral over computable numbers without changing much, but not the more general Lebesgue integral. This mean
505.
by dooglius 5y ago
Braille and wheelchairs are the equivalent of a cure for autism, as I envision it. Why do these not count as "avoid[ing] our shared responsibility of accommodating for differences, by erasing the differences"? > They're no
506.
by dooglius 5y ago
> I managed to get logged in to the SDF MetaArray, open mutt and send an email Is there an easier way to set something up to contact 911 via command line in a pinch?
507.
by dooglius 5y ago
That may have been what he had in mind, but he made no indication as to there being a conditional probability. Furthermore, in the context of where he was going with it, I recall that there wasn't one either so he was getting the wrong
508.
by dooglius 5y ago
I had a professor in college--teaching a queueing theory class no less--claim it was 1/3 as long as you didn't care about the order, and I interrupted the class for a good amount to explain it was not.
509.
by dooglius 5y ago
Who is the "we" who wants to keep "in sync" with the Earth's rotation to such high precision? Obviously having 3:30 pm suddenly become the middle of the night would be bad, but we're talking a delta of 18 secon
510.
by dooglius 5y ago
I didn't get the impression the film used her name

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