- C++ Middleware Writer - 4 Updates
- C++ is a complicated language? - 3 Updates
- Bug in the C++ 2011 specifications - 6 Updates
- Backporting std::move code - 1 Update
- Backporting std::move code - 2 Updates
| red floyd <no.spam@its.invalid>: Aug 18 09:39AM -0700 Let us also not forget the fact that the toxic waste lines run through the playground. |
| jacob navia <jacob@jacob.remcomp.fr>: Aug 18 07:26PM +0200 Le 18/08/2016 à 10:17, David Brown a écrit : > Sites like this have a great tendency to talk about what "everyone > knows" or what scientists "disagree" on. It is almost invariably nonsense. Maybe. Nonsense is to believe anybody knows how life started in this planet, what life is, and what we are. Science has NO explanation for this questions, our ignorance is a fact. Yes, we believe that we will find eventually an explanation how the genetic code arised, how *meaning* started in this part of the universe. Some people let's call them "religious" people, say that they know the answer (god did it) but actually they are worse off than the ones that realize that they do not know! I do not know who am I, nor do I know how life started. At least I know that, I realize my ignorance. Because once you realize that, you can start learning. Nobody can learn if he thinks he knows already everything. The religious people have brought death and destruction to mankind since ages. "My god is better than yours" yell the religions all across the world. Some 3 000 gods in active existence today, and countless wars and murders committed by the same gods. Figments of a primitive mind, religions are a plague. Abstracting from that and concentrating in the problems at hand, we see history, i.e. evolution. We have been able to retrive the history of the planet, the long story of life. But history is not an explanation. It is a description of what happened. We could be very well be the software constructs of some designer, since we are almost able now to do the same thing. In the near future, humans will start writing biological systems. Bacteria are useful as universal machines, that can be programmed to build stuff for us. Starting with the biological example, we will be able to write a new genetic code, as some scientists are already starting to do. Then the question of how the hell this all started will be with us again and again. Will be ultimately able to construct a circuit that can realize that it is living and start writing circuits of his own? Surely such a circuit would be interesting for finding out the general principles isn't it? And before we start critizing the eye, as you do David, let's start doing such a camera ok? With a sensitivity of just a single photon? With a ridiculously low amount of power? True, humans do not see as well as flies or birds, because we do not fly, as you can convince yourself, if you try, from a chair :-) But we have an incredible machine at our disposal. Not only the camera but the circuit, David, the circuit between your ears. Billions of processors running inn parallel, able not only to realize its ignorance, but from there able to start LEARNING! Science is learning David. Our circuit is able to do that. Why? We do not know. But we are learning. Religion is bad because it leads you into ignoring that you do not know, actually, who you are. Ignorance is the ally of religion. Learning is the only cure against religion. jacob |
| David Brown <david.brown@hesbynett.no>: Aug 18 10:53PM +0200 On 18/08/16 19:26, jacob navia wrote: > Nonsense is to believe anybody knows how life started in this planet, > what life is, and what we are. Science has NO explanation for this > questions, our ignorance is a fact. Science has a good number of partial explanations for plausible ways for life to start, but no complete hypotheses as yet. And of course we are unlikely to ever know how life /did/ start - the best we can hope for is ways that life /could/ have started. But there is no doubt that there are plenty of things here that scientists don't know. After all, if we knew all the answers, there would be no need for more science! For scientists, ignorance is something to be accepted, and embraced as a challenge - not something to be denied or hidden. > Yes, we believe that we will find eventually an explanation how the > genetic code arised, how *meaning* started in this part of the universe. Certainly we hope that we will find one (or more) plausible explanations about how genetic code arose. As for how "meaning" started, that is, I think, more philosophy than science. (Or do you mean "conciousness" or "thought" here?) > Some people let's call them "religious" people, say that they know the > answer (god did it) but actually they are worse off than the ones that > realize that they do not know! Absolutely. Religious people, or at least /some/ religious people, feel they already know the answer to everything. Life must be pretty boring for them. > I do not know who am I, nor do I know how life started. At least I know > that, I realize my ignorance. Because once you realize that, you can > start learning. Nobody can learn if he thinks he knows already everything. Agreed. I don't know who you are either :-) > ages. "My god is better than yours" yell the religions all across the > world. Some 3 000 gods in active existence today, and countless wars and > murders committed by the same gods. It is human nature to fight. If people didn't fight each other over religion, they would do so for other reasons. In fact, I think a good many conflicts that appear to be religious are more about money, power, land, or resources. So while many terrible things have been done, and continue to be done, in the name of religion and "my god is better than your god", they can't get /all/ the blame. > It is a description of what happened. > We could be very well be the software constructs of some designer, since > we are almost able now to do the same thing. It is certainly a possibility. The flaws and inefficiencies in biology argue against a "designer" of some sort, at least at the level of the life we see around us now. But the known facts and evidence don't rule out the possibility that the earliest cells were designed, and the rest of life is a science experiment left to run its course. As scientists, we can't rule out any particular explanations - but we can look for more "down to earth" explanations that fit with the rest of our scientific theories. > build stuff for us. Starting with the biological example, we will be > able to write a new genetic code, as some scientists are already > starting to do. It is already being done, though the scale will no doubt increase. > and again. > Will be ultimately able to construct a circuit that can realize that it > is living and start writing circuits of his own? Self-conciousness is (as far as we know) an emergent property. It will take a "circuit" of substantial complexity, but there is no reason for it to be impossible. > principles isn't it? > And before we start critizing the eye, as you do David, let's start > doing such a camera ok? I don't have to be able to design a better eye before I can criticise the existing human eye. And nature has already evolved significantly better eyes than ours (at least, better for the purposes we now use them for). However, if our distant ancestors' eyes had been as good as birds' eyes, then they would not have evolved such complex brains to compensate for the weaknesses of the eye - and perhaps then never have evolved brains complex enough to become concious. > :-) > But we have an incredible machine at our disposal. Not only the camera > but the circuit, David, the circuit between your ears. Indeed, a large part of our rather impressive brain is devoted to vision. So while birds vision centres are rather simple (in comparison) because their eyes really can see colour, our vision centres are complex so that - amongst other things - we have the illusion of seeing in colour despite the physical limitations of the eye. It really is a marvellous system - but it is not one that would come about through design. If you tried to build a high resolution electronic vision system, there are two ways to do it. You could use a decent camera and lens along with a small processor and simple software - or you could use a limited camera with a poor quality lens, and use massive processing power and complex software algorithms to interpolate over time and multiple images with digital filters to fill in the missing details. Which would be the more sensible design, given a free choice of parts? |
| jacobnavia <jacob@jacob.remcomp.fr>: Aug 18 11:49PM +0200 Le 18/08/2016 à 22:53, David Brown a écrit : > over time and multiple images with digital filters to fill in the > missing details. Which would be the more sensible design, given a free > choice of parts? Evolution tells us that some 60 million years ago we were a kind of rat. That after the disparition of dinosaurs those rats started climbing to the trees and stayed living there for millions of years. But around six million years ago, a monkey had a fever, and a virus entered its genome and a reorganization of many genes ensued. The brain of the monkey started to grow as no other species experienced before. New software was possible with that circuit. Cilindrical structures appeared in the surface of the circuit, that increased in size. In parallel, women evolved wider hips, to accomodate for a larger circuit at birth. I do not know how it happened, nor do I know definitely if that story is lacking some essential pieces, but that is the primates story. Just animals, like so many others and yet one day, they decided to walk upright. So that they can see clearly the stars. They developed the first invisible tool: a symbolic language. SYMBOLS. The genetic code is about SYMBOLS as all software. A sequence of three DNA bases MEANS a specific amino-acid among the 20 that life uses to build everything. The sequence of proteins and enzyms is ENCODED in ADN with a code of 3 basepairs per amino-acid. There are START and STOP codons, and an interpreter, the ribosome. The interpreter reads the code and emits at the other side a growing chain that automatically folds in place. The genetic code is the burst of MEANING (software) in this planet. Consciousness is the evolution of that meaning to a conscious stage. We are nature's latest innovation and one that has never existed before, apparently. Around four thousand million years life did not need nor evolved consciousness. Until six million years ago and that monkey that started acting up and walking upright so that the stars could be more easily grasped. Why? I do not know. And when I think that it could be true that there is a creator, it is not a "god" but that being that we all can see and taste and smell and touch. Life. Life is a single being, and we are part of it. All life in earth uses the same code, the same basic biochemistry, the same processes from bacteria to man. Life is an impressive being, around 4 billion years old. It covers all the surface of this planet, and probably goes deep below, at least 4 Km deep you can still find bacteria and living things. This being has changed the composition of the atmosphere of the planet itself with his breathing, thriving on solar energy, chemical energy at the depths of the ocean, chemical reactions in inhospitalable environments. It can survive a meteor striking a global wound, survive global disasters like the floods of lava, hundreds of millions of years ago. Life is a VERY tough being. Does this being have a consciousness, could we communicate with the whole of life in this planet? I do not think so, such a being is so incredible different than me, a mere human, that I have no idea how I could tell him something, even if such a thing as ideas and concepts would mean anything to it. But one thing I am sure: it is not god. It is not invisible, and we eat parts of its body every day, we breathe the oxygen the plants produce every day, we are connected to it by zillions of bacteria that live in our skin and guts, by our total dependence on other kinds of life to just survive. Life doesn't exist anywhere else but in the context of this being. Is it possible to speak about a single being? Yes, it is. I repeat: o The same genetic code in all beings o The same biochemical processes like respiration, (mitochondria), digestion, and the same 20 amino-acids that build our flesh, the plants, the dogs, the amoeba, everything. Just the SAME 20 building blocks! Please do not confuse LIFE with the gods we create at our own image. Life is nothing like that, we do not have any information on its purpose, why some species appear, why they are discontinued and disappear. We, do not know either what really happened to those monkeys 6 million years ago, but the descendants of those monkeys today do wonder... Why? It was a "random mutation" somewhere? I am skeptic about random process. They surely have a place in living beings, as a source of diversity, but always in a very controlled manner. And I am more and more fascinated by the growing similarities between software environments and the maintenance of the genetic code/programs that organisms use. Did you know that some species encrypt their genome? A species of viruses has many times the size of our own genetic program. Thousands and thousands of genes are stored in the genome of those viruses in something that looks more and more like a living data-base! We have text editors, and we should be grateful because without them we would be dead in a few years. Text editors discover errors in transcription and correct them. Genes are stored in different kind of storage spaces: Packed, semi-opened and ready. They are ANNOTATED with COMMENTARIES (methyl groups added to the DNA code at specific places) that determine if they are to be used or not at all. This is a new discovery (the annoations) that has been done relatively recently and grasped in its full significance only since a few years. Since those annotations are transmitted from mother to child, it is a new kind of inheritance: the commentaries. A new being is started with most commentaries in the virgin state, but the mother and the father let pass some of those. There is a whole new world of software there, where life opens up her books for us. LITERALLY. She shows us the book of life base after base, gen after gen, organism after organism. We just have to learn to read. I do not believe in a god but I am sure that life exists. jacob |
| jacob navia <jacob@jacob.remcomp.fr>: Aug 14 09:35PM +0200 Le 14/08/2016 à 17:32, Mr Flibble a écrit : > C++ is a complicated language? No shit. Have you only just realized this? No, since quite a long time actually. > C++ was complicated before C++98 so imagine how complicated it is now. I do not need to imagine it. Just look at it. > However, paradoxically, C++'s complexity can result in simpler C++ > PROGRAMS which is a GOOD THING (tm). Yes, but the problem is brittleness. Without continuous maintenance any small thing that changes and unrelated code to the point of failure could go wrong. Finding the point of failure becomes extremely complex for the unaware maintenance programmer. For instance (in another message) you say that <quote> My new GUI library "neoGFX" doesn't use signals and slots as signals and slots are an old solution to an old problem. Instead all we need to do is: button1.clicked([](){...}); <end quote> Are you sure? The new syntax does really replace neatly the code for slots/signals? An object (a button) that sends signals was an analogy quite easy to follow. What does the new syntax bring to the code actually? Because apart for being very small, it looks very unreadable to me. Of course I am not a C++ head but I would prefer the old slot/signal framework. It is a proven analogy, many libraries use it, and code written like that has a KNOWN structure, callbacks, etc. Yours is a new way of doing the same thing, what can be very clever but for the maintenance programmer is yet another pain in the ass really. Sorry but I couldn't resist :-) |
| Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Aug 14 04:32PM +0100 C++ is a complicated language? No shit. Have you only just realized this? C++ was complicated before C++98 so imagine how complicated it is now. However, paradoxically, C++'s complexity can result in simpler C++ PROGRAMS which is a GOOD THING (tm). /Flibble |
| Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Aug 14 10:01PM +0100 On 14/08/2016 21:39, jacob navia wrote: > WHAT IS THE ADANTAGE of the new syntax in terms of software engineering? > (Besides being more incomprehensible) > Thanks in advance for your explanations. My solution with lambdas is actually simpler than signals and slots. I can only repeat my earlier reply: if you find C++ lambdas too complicated then I suggest you use a different programming language. /Flibble |
| Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Aug 14 02:51PM +0100 On 14/08/2016 14:26, Alf P. Steinbach wrote: > compilers say about it: > struct S{ int x; }; > auto main() -> int Do you realize how demented that looks? Take your meds and write: int main() like any sane person would. >> _ > </compilation> > Oh my, they disagree! Intel's compiler also allows the assignment. > What do you think the standard says about it? According to the Standard it is an rvalue however it also has a *name*. /Flibble |
| Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Aug 14 02:57PM +0100 leigh@server:~$ cat test.cpp struct s { int n; }; int main() { constexpr int z1 = 0; const int z2 = 0; int z3 = 0; void* p0 = 0; void* p1 = z1; void* p2 = z2; void* p3 = z3; void* p4 = s().n; } leigh@server:~$ g++ -std=c++11 test.cpp test.cpp: In function 'int main()': test.cpp:12:13: error: invalid conversion from 'int' to 'void*' [-fpermissive] void* p1 = z1; ^ test.cpp:13:13: error: invalid conversion from 'int' to 'void*' [-fpermissive] void* p2 = z2; ^ test.cpp:14:13: error: invalid conversion from 'int' to 'void*' [-fpermissive] void* p3 = z3; ^ test.cpp:15:17: error: invalid conversion from 'int' to 'void*' [-fpermissive] void* p4 = s().n; ^ leigh@server:~$ clang -std=c++11 test.cpp test.cpp:12:8: error: cannot initialize a variable of type 'void *' with an lvalue of type 'const int' void* p1 = z1; ^ ~~ test.cpp:13:8: error: cannot initialize a variable of type 'void *' with an lvalue of type 'const int' void* p2 = z2; ^ ~~ test.cpp:14:8: error: cannot initialize a variable of type 'void *' with an lvalue of type 'int' void* p3 = z3; ^ ~~ test.cpp:15:8: error: cannot initialize a variable of type 'void *' with an rvalue of type 'int' void* p4 = s().n; ^ ~~~~~ 4 errors generated. leigh@server:~$ /Flibble |
| Ian Collins <ian-news@hotmail.com>: Aug 15 07:23AM +1200 On 08/15/16 03:23 AM, Manfred wrote: > appear not to be irrelevant (my gcc always outputs X! by the way), this > confirms the complexity of the language, IMHO. Meaning that the original > cleanliness of the language risks to get polluted by newer "improvements" Which compilers are they? -- Ian |
| jacob navia <jacob@jacob.remcomp.fr>: Aug 14 07:06PM +0200 Le 14/08/2016 à 17:23, Manfred a écrit : > this confirms the complexity of the language, IMHO. Meaning that the > original cleanliness of the language risks to get polluted by newer > "improvements" Exactly the point I am trying to make. Interactions between each new "feature" with old features, added to things that were already wrong (the ambiguity between 0 as an integer and 0 as a null pointer) that weren't fixed but now reachy new places where they can bite the unaware. What I want to say is this: C++ is reaching the point where only a machine can follow the extremely complex rule's interaction. Programmers can't follow and when they use the language they CAN'T foresee exactly what will happen. The example I gave is just 12 lines of C++! It is not the sheer size of the example, it is just that humans can't follow the rules! jacob |
| Chris Vine <chris@cvine--nospam--.freeserve.co.uk>: Aug 14 09:55PM +0100 On Sun, 14 Aug 2016 22:52:02 +0200 > [drivel snipped] You are still missing the point. Your example is highly artificial. No one in their right minds would write code of that kind for a meaningful purpose, and I am certainly not going to spend the time reaching a view about which of the views expressed is correct. |
| jacob navia <jacob@jacob.remcomp.fr>: Aug 14 11:08PM +0200 Le 14/08/2016 à 22:55, Chris Vine a écrit : > jacob navia <jacob@jacob.remcomp.fr> wrote: >> [drivel snipped] > You are still missing the point. Your example is highly artificial. Of course not!!!!!!! That is a condensate of a problem that will appear in a huge program where conceptually those 12 lines are dispersed in several different files across several classes and templates and what have you!!!!! > No one in their right minds would write code of that kind for a > meaningful purpose, THAT IS A MINIMAL EXAMPLE OF THE PROBLEM MAN! Please turn on the brain before posting! A "minimal example" in compiler parlance, is a very small code snippet that highlights a problem that could be dispersed in several different locations! > and I am certainly not going to spend the time > reaching a view about which of the views expressed is correct. Of course not. If you do not feel like not doing it do not do it! But then just keep silent since you have nothing to say and the only thing that you can say is that I am just speaking "drivel" that can be ignored, without engaging a single argument or technical point |
| ram@zedat.fu-berlin.de (Stefan Ram): Aug 14 03:26PM > lhs += x; > return std::move(lhs); >} You have an object as a return value and then move into this object. lhs is an lvalue, not an xvalue, so RVO might not move from it without the move as far as I understand it. I have no experience in this field. But the class Signalsource could get methode to return its resources and bring the object into a valid but resourceless state and an implicit constructor to build a SignalSource from this. return lhs.resources(); Then the returned object would be built from those resources. |
| bitrex <bitrex@de.lete.earthlink.net>: Aug 14 06:33PM -0400 On 08/14/2016 05:27 PM, Öö Tiib wrote: > efficiency where needed. There were no rvalue-references (from what it > is safe to move or to swap) so if someone wanted to move from reference > to temporary then he had to cast constness away. Nice, thank you for your insight. I've started using C++11 a bit on the desktop and the unique_ptr smart pointer syntax does make life a lot easier. Unfortunately this particular thing is for an embedded platform, so all that cool automatic memory management stuff that assumes a system MMU is out the door. |
| "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com>: Aug 14 11:58PM +0200 On 14.08.2016 17:11, bitrex wrote: > rhs += x; > return std::move(rhs); > } I think this is probably not your actual code. Your actual code is probably templated on SignalSource, in which case the && is a universal reference. In the non-templated code given above, && is an rvalue reference, which would only permit rvalue expression as actual argument. Anyway, you can either • remove the move optimization (just copy things) or • implement /explicit/ move operations. > of objects on the stack when the source/destination is going to be > destroyed anyway, so I didn't know if there was some "canonical" way to > backport this. Nope, but if, after measuring the simple copy solution, you find that moving is really required, then instead of implementing your own explicit C++03 move operations you could look up Andrei Alexandrescu's Mojo article in DDJ. Cheers & hth., - Alf |
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