- Boost - lists.preview.boost.org

[preprocessor] Appveyor weirdness
by Edward Diener 14 Sep '20

14 Sep '20

In my appveyor.yml file for preprocessor one of the b2 command lines for a test run uses an explicit alias for the target. When run in appveyor.yml I get the messages: notice: could not find main target preprocessor_limits notice: assuming it is a name of file to create . and don't know how to make <e>preprocessor_limits Yet when I run the same test locally using the preprocessor_limits target, everything works fine. Is Appveyor somehow different when running Boost Build tests than when I run it locally ?

1 0

No doc for qvm in 1.74 distro
by Edward Diener 12 Sep '20

12 Sep '20

There is no doc for the qvm library in the 1.74 distro.

2 1

[JSON][review] Should there be an equality operator/function?
by Hadriel Kaplan 12 Sep '20

12 Sep '20

Howdy, I’ve been testing Boost.JSON in preparation for writing a review, and one thing that I found surprising might be better discussed in a separate thread, so here goes… There’s currently no comparison function or operator to compare one json::value with another. While I appreciate that a deep comparison isn’t cheap - it’s O(N) for the average case but O(N^2) in the worst case I believe - I still think it’ something a JSON-based container value type should have out-of-the-box. It’s something other popular JSON libraries offer; usually with equality operators, although a named function would be ok too if that was required instead. I hit the lack of it almost immediately, since test code/assertions frequently check equality. I’m not sure how frequently it’s used for run-time code in general, however. -hadriel

1 1

Looking for a review manager for Real
by Damian Vicino 10 Sep '20

10 Sep '20

Hi, GSOC finished and we are almost-ready for proposing to review a new library, Real. We are looking for a volunteer to be a review manager for it. Best regards, Damian

9 15

Do I need to use boost::mutex in deadline_timer?
by Jupiter 10 Sep '20

10 Sep '20

Hi, I used boost::asio::io_service for a single thread implementation but with multiple boost::asio::deadline_timer objects, because it is a single thread, I don't think I need to use boost::mutex to lock and unlock tasks running by deadline_timer, am I wrong about it? Thank you. Kind regards, jupiter

3 4

Re: [boost] boost.real
by Kostas Savvidis 09 Sep '20

09 Sep '20

Hi Damian, Laouen, I have been able to compile the test programs with your library after making some simple changes. The patch is below the message. However the example program from your documentation still does not compile, unless I comment out some lines - you can see the listing below. I ran a tricky calculation which is from the Aberth book, your program is able to give the answer and moreover the true value is indeed between the upper and lower bounds that your program gives. This is good! The conclusion is that your library can do useful work, but it is very limited in capability. No special functions, trig is there but not working well, and no simple way to interface with linear algebra. I may want to use it at some point, but I would need at least the ability to cast int and double to your boost::real::real type, because as it is now, the only way to import numbers into your software seems to be through std::string. Finally what seem to be some bugs: 1) unsigned int real::maximum_precision = 10; // error: specializing member 'boost::real::real<int>::maximum_precision' requires 'template<>' syntax 2) auto it = e.cbegin(); // error: 'using real = class boost::real::real<int>' {aka 'class boost::real::real<int>'} has no member named 'cbegin' 3) real::sin(f) // enters infinite loop 4) real c = (std::string)"0.999999"; prints: c: [0.99999899999999999999999999999999999999999999999999999999999999999999999999999999999999999933600778729, 0.99999899999999999999999999999999999999999999999999999999999999999999999999999999999999999982691714296] as far as i can see the interval is incorrect ! Best Regards, Kostas ============================================================================================= diff -r -u real.orig/integer_number.hpp real/integer_number.hpp --- real.orig/integer_number.hpp 2020-09-07 16:22:04.000000000 +0300 +++ real/integer_number.hpp 2020-09-08 14:11:22.000000000 +0300 @@ -103,7 +103,8 @@ } // this function always expects (*this) to bigger than other, so if borrow is not zero at the end // there should be error - if(borrow != 0); + if(borrow != 0) + ; //throw subtraction_number_required_lower_exception(); diff -r -u real.orig/real_rational.hpp real/real_rational.hpp --- real.orig/real_rational.hpp 2020-09-07 16:22:04.000000000 +0300 +++ real/real_rational.hpp 2020-09-08 11:59:51.000000000 +0300 @@ -262,7 +262,7 @@ // constructor to generate get number from string constexpr explicit real_rational(std::string_view num){ // searching for "/" in string - size_t pos; + size_t pos=0; bool found = false; std::string_view num1, num2; pos = num.size(); ============================================================================================= #include <iostream> #include <string> #include <real/real.hpp> using real = boost::real::real<int>; //unsigned int real::maximum_precision = 10; //unsigned int real_algorithm::maximum_precision = 10; int main() { real c = (std::string)"0.999999"; real d = (std::string)"0.999999"; real e = c + d; std::cout << "c: " << c << std::endl; std::cout << "d: " << d << std::endl; std::cout << "e=c+d: " << e << std::endl; // ANSWER IS WRONG ??!!! // for(auto it = e.cbegin(); it != e.cend(); ++it) { // std::cout << "e iteration " << it.approximation_interval << std::endl; // } real g = (std::string)"0.999998"; std::cout << "g: " << g << std::endl; if (g < d) { std::cout << "g < d --> true" << std::endl; } else { std::cout << "g < d --> false" << std::endl; } real h = d - g; std::cout << "h=d-g: " << h << std::endl; std::cout << "h++ is: " << h+real("1.0") << std::endl; { // Example from Aberth 1992, Precise Computation Using Range Arithmetic real a("77617.0"); real b("33096.0"); std::cout << "\n\n" << "a: " << a << std::endl; std::cout << "b: " << b << std::endl; real f = real("333.75")*b*b*b*b*b*b + a*a*(real("11.0")*a*a*b*b-b*b*b*b*b*b - real("121.0")*b*b*b*b-real("2.0")) + real("5.5")*b*b*b*b*b*b*b*b + a/(real("2.0")*b); // should be -0.827396 std::cout << "f: " << f << std::endl; //std::cout << "sin(f): " << real::sin(f) << std::endl; // doesn't come out of the loop } return 0; }

2 1

[LEAF] Review Results
by Michael Caisse 09 Sep '20

09 Sep '20

I want to thank Emil for his patience for the publishing of the review results as life got in my way. Thank you Emil for submitting LEAF to be reviewed for inclusion into Boost. As an already-Boost-author, you knew what you were getting into and continued into the process. I also want to thank you for once again pushing our thoughts on error handling. -------- Result -------- This is the part everybody scrolls to the bottom to read, so let’s just put it at the top. Boost.LEAF is ACCEPTED into Boost. After the following modifications are made to the library, the repository can be transitioned to Boost for inclusion into the next release (with the release cycle timing constraints): Specify the TLS requirement sooner in the documentation. Optional usage of Boost.Config to perform all of the Boost Configy things. (further discussion on this below) Macro naming and general Boostification clean-up. -------- Reviews -------- There was a good amount of discussion about the library on both the dev and user mail lists. I want to personally thank those who got involved in the review. You make the process work! Result summary: Accept: 7 Reject: 1 No-decision: 3 The no-decision reviews provided valuable input and discussion threads. While it would be my preference to have the review authors provide a final verdict, I was grateful for the time and energy they spent with the library and formulating thoughts into emails for discussion. Some comments from reviews: “I find function preload() really great and novel. … This really makes the error reporting code brief, clean and bug-free.” “I like LEAF very much and there's a lot offered here…” “I like it.” “...it allows bridging multiple error handling strategies and usage patterns in an efficient way.” About the docs: “They look good and manage to explain hard concepts in a very approachable fashion.” “The documentation is great -- in terms of styles it's probably the best I've seen for a C++ library.” “Clear, friendly and complete.” -------------- Some Thoughts -------------- While there was overwhelming consensus that LEAF should be included into Boost, the process is not democratic. I have spent considerable time understanding the concerns raised in each of the reviews and in particular the singular rejection. Emil took time responding to each of the reviews. The exchanges were fruitful and both “conditional accept” and “reject” reviewers changed their verdicts to accept along the way. Most of the concerns were amicably resolved. I am comfortable with the design choices and implementation made by the author for the remaining items. One reviewer brought up the re-implementation of Boost.Config type facilities. This of course is a complex issue for a library with zero dependencies. The ability to simply drop the Boost.LEAF directory into a project and run is a definite plus for a specific user segment. Being able to modify a single Boost.Config repository to support WackyCompiler14 targeting LEG Core and get a bunch of libraries for the ride is also a plus. Emil and I have discussed these concerns and the best choice seems to be defaulting to zero dependencies and the option to pull in Boost.Config to provide configuration type facilities if needed. Accepting a library into Boost is as much about the library as it is bringing the author into a group. While Emil is already part of the author crowd, it was clear to me through his careful, informative, and patient responses that the addition of Boost.LEAF brings professional maturity that strengthens the community. A user with more than a year of experience with the library voted acceptance based on the “qualities of the library itself and the responsiveness and openness for feedback of its author.” Throughout the review period, Emil integrated feedback to both the documentation and code in another branch. It was wonderful to see the community provide input and the author respond so quickly to produce a better final result. Thank you Emil for your vision of better error handling and striving to bring us along! -- Michael Caisse Ciere Consulting ciere.com

3 2

[log] logfile not created where expected
by Barend Gehrels 08 Sep '20

08 Sep '20

hi, I encountered a bug, most probably, in Boost.Log It is reproduceable in the tutorial_logging.cpp : https://www.boost.org/doc/libs/1_74_0/libs/log/example/doc/tutorial_logging… The short code should create a file named "sample.log". But it does not, instead it creates a file called "00000.log", with the expected lines logged in that file. If I compile and run exactly the same tutorial in Boost 1.70, the file sample.log is indeed created with the same content. The problem is already there in Boost 1.73 What is the problem? Is there a workaround for it? Thanks, regards, Barend

3 2

Re: [boost] Review Manager needed for Boost.Lambda2
by Mateusz Loskot 08 Sep '20

08 Sep '20

Bjorn, thank you for reminding me about it. I've been offline for several weeks and I might have missed it happened already (lots of communication moved to Slack too). Mateusz Loskot, mateusz(a)loskot.net (Sent from mobile, may suffer from top-posting) On Tue, 8 Sep 2020, 20:39 Bjorn Reese, <breese(a)stofanet.dk> wrote: > On 2020-09-08 19:39, Mateusz Loskot via Boost wrote: > > On Tue, 8 Sep 2020 at 17:02, Peter Dimov via Boost > > <boost(a)lists.boost.org> wrote: > >> > >> I turned this into a mini-library, https://github.com/pdimov/lambda2, > and > >> I'd like to submit that to Boost. > >> > >> I'm looking for a review manager. > > > > FYI, added to the schedule. > > Strictly speaking, he needs an endorsement first. >

2 1

buffer_size behavior in boost::iostreams::filtering_istream
by Justin McManus 07 Sep '20

07 Sep '20

I have some code that works as intended, but it requires setting a buffer_size parameter to zero on a std::ifstream pushed onto a filtering chain, and I'd like to understand why, to ensure I'm not introducing a bug or a hack. I have essentially the following code: -------------------------------------------------------------------------------------------------------- std::ifstream m_jf("json_filename", std::ios_base::in | std::ios_base::binary); std::locale utf8_locale("en_US.UTF-8"); m_jf.imbue(utf8_locale); boost::iostreams::filtering_istream m_inbuf; m_inbuf.push(boost::iostreams::bzip2_decompressor()); m_inbuf.push(m_jf); std::string m_line; while (std::getline(m_inbuf, m_line)) { // Process the current line from the JSON file } -------------------------------------------------------------------------------------------------------- What I find is that the std::getline call will fail before the code has reached the EOF. It will always fail at the same line in a given JSON file, but it will fail on different lines in different JSON files. It's perfectly reproducible. However, if I change lines 4 and 5 to m_inbuf.push(boost::iostreams::bzip2_decompressor(), *0*); m_inbuf.push(m_jf, *0*); then the problem goes away. My question is, Why does setting the buffer_size parameter to zero solve the issue? What does this do, exactly? I saw the suggestion to set the buffer size this way from an old post in 2009, and it appears to work, but I'd like a deeper understanding of what's happening under the hood. If the buffer size is set to zero, what does the underlying implementation do, and how might this influence whether std::getline fails before the EOF? Thanks very much, Justin -- Justin McManus, Ph.D. Principal Scientist Lead Computational Biologist and Statistical Geneticist Kallyope, Inc. 430 East 29th Street, Suite 1050 New York, NY 10016

3 4