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boost::units - converting from one derived_dimension to another across systems (imperial to metric)
by Matt Vinson 21 Nov '18

21 Nov '18

Michael Powell: A) I hope to get Boost.Units to convert all these for me. I am replacing my own unit conversion classes with Boost.Units so there are no masking certain details, magic numbers, etc! Fingers Crossed. B) Boost.Units looks promising. Good to hear it has strong support. I'll keep at it. Thanks!// Steven Watanabe: Got it! You've been very patient and awesome. Thank you, yet again.I updated to this because I do need mass for density conversions:typedef boost::units::make_system< boost::units::us::inch_base_unit, boost::units::us::pound_base_unit, boost::units::us::pound_force_base_unit >::type ip_system; Any issues you see with boost::units::us::pound_base_unit for mass && boost::units::us::pound_force_base_unit for force? If I don't hear from you, I'll presume it's okay. My density unit testing* still passed after adding boost::units::us::pound_force_base_unit so I don't think there are issues. *each of these are converted to the other. enum class DENSITY : char { K_FT3 = 0, K_IN3 = 1, LB_FT3 = 2, LB_IN3 = 3, MT_M3 = 4, MT_CM3 = 5, MT_MM3 = 6, KG_M3 = 7, KG_CM3 = 8, KG_MM3 = 9, LAST = 10 }; On Tuesday, November 20, 2018, 9:09:45 PM CST, boost-users-request(a)lists.boost.org <boost-users-request(a)lists.boost.org> wrote: Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. Re: boost::units - converting from one derived_dimension to another across systems (imperial to metric) (Michael Powell) 2. Re: Program Options documentation is anaemic (Gavin Lambert) 3. Re: boost::units - converting from one derived_dimension to another across systems (imperial to metric) (Steven Watanabe) 4. Re: Enquiry on boost.geometry and intersection() (Adam Wulkiewicz) ---------------------------------------------------------------------- Message: 1 Date: Tue, 20 Nov 2018 20:55:19 -0500 From: Michael Powell <mwpowellhtx(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] boost::units - converting from one derived_dimension to another across systems (imperial to metric) Message-ID: <CAMEoF_GFTg_Fx4haDdb2i65fEaOB_hnG8QmrgshMSG5-0XT5mQ(a)mail.gmail.com> Content-Type: text/plain; charset="UTF-8" On Tue, Nov 20, 2018 at 8:47 PM Matt Vinson via Boost-users <boost-users(a)lists.boost.org> wrote: > > degski: I do not think am making the "nauseam" mistake. My issue is using Boost.Units correctly which I concede is difficult for me but I am reading the docs and trying to get it. > In our field of engineering, we use Kg as a force; not a mass. (We also use pound as a force; not a mass - for your "UK's Weights and Measures Act 1963" counterpart). That said, I should not have made the mistake of using Kg as a force in Boost.Units, it's true. Shame on me. > My task is to convert between lineal forces: k/ft, k/in, lb/ft, lb/in, kN/m, kN/cm, kN/m, N/m, N/cm, N/m, Metric ton/m, Metric ton/cm, Metric ton/mm, Kg/m, Kg/cm, Kg/mm. These are all force/length. Coming from an energy oil and gas background applying Boost.Units, that's a difficult conversation to have especially when "units" are used, but in fact are masking certain details, magic numbers, etc, confounding their dimensions. > Steven Watanabe: Thank you, again. > #1: I was not trying to say it's wrong; sorry. Just that I did not see 'length' and opted for the one that did. The unit's are correct, as you say. > #2: This is an error to start with Kg(force)/meter. I can start with N/meter. I've changed this variable name to newton_per_meter and the conversion factors. I can tell you this much; once you get reasonably proficient with Boost.Units, there is a strong compiler confidence in correctness once you have your dimensions, units, etc, meshing well together. By that I mean, in truth, compile time confidence. The compiler / Boost.Units will tell you when you have it wrong, and it will compile when you have it correct. That's a major plus in my book. Cheers, best of luck! > *.h----------------------------------------------------- > > namespace dimensional_analysis { > > typedef boost::units::length_base_dimension::dimension_type length_dimension; > > typedef boost::units::mass_base_dimension::dimension_type mass_dimension; > > typedef boost::units::make_system<boost::units::us::inch_base_unit,boost::units::us::pound_base_unit>::type ip_system; > > namespace lineal_force { > > typedef boost::mpl::divides<boost::units::force_dimension,boost::units::length_dimension>::type lineal_force_dimension; > > namespace imperial { > > //////////////// > > ////lb/in, right? > > ////boost::units::force_dimension = pound > > ////boost::units::length_dimension = in > > //////////////// > > typedef boost::units::unit<lineal_force_dimension,lengths::ip_system> lineal_force_unit; > > } > > namespace si { > > //////////////// > > ////N/m, right? > > ////boost::units::force_dimension = newton > > ////boost::units::length_dimension = meter > > //////////////// > > typedef boost::units::unit<lineal_force_dimension,boost::units::si::system> lineal_force_unit; > > } > > }//lineal_force > > }//dimensional_analysis > > *.cpp----------------------------------------------------- > > //Imperial lb/in to SI N/m > > BOOST_UNITS_DEFINE_CONVERSION_FACTOR( > > dimensional_analysis::lineal_force::imperial::lineal_force_unit, > > dimensional_analysis::lineal_force::si::lineal_force_unit, > > double, > > 175.1268369864); // exact conversion > > BOOST_UNITS_DEFAULT_CONVERSION( > > dimensional_analysis::lineal_force::imperial::lineal_force_unit, > > dimensional_analysis::lineal_force::si::lineal_force_unit); > > //SI N/m to Imperial lb/in > > BOOST_UNITS_DEFINE_CONVERSION_FACTOR( > > dimensional_analysis::lineal_force::si::lineal_force_unit, > > dimensional_analysis::lineal_force::imperial::lineal_force_unit, > > double, > > 0.1837185501); // exact conversion > > BOOST_UNITS_DEFAULT_CONVERSION( > > dimensional_analysis::lineal_force::si::lineal_force_unit, > > dimensional_analysis::lineal_force::imperial::lineal_force_unit); > > //Imperial to SI. This should convert lb/in to N/m and return 175.1268369864 (N/m) > > //But it does not. Its converting lb (mass) to Kg (mass), 0.454 > > const auto t2 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::si::lineal_force_unit>>( > > 1.0 * dimensional_analysis::lineal_force::imperial::lineal_force_unit::unit_type()); > > //Again, Imperial to SI. This should convert lb/in to N/m and return 175.1268369864 (N/m) > > //But it does not. It returns lb (mass) to Kg (mass) > > const auto t3 = boost::units::conversion_factor( > > dimensional_analysis::lineal_force::imperial::lineal_force_unit::unit_type(), > > dimensional_analysis::lineal_force::si::lineal_force_unit::unit_type()); > > //SI to Imperial. This should convert N/m to lb/in and return 0.1837185501 (lb/in) > > //But it does not. Its converting Kg (mass) to lb (mass), 2.205 > > const auto t1 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::imperial::lineal_force_unit>>( > > 1.0 * dimensional_analysis::lineal_force::si::lineal_force_unit::unit_type()); > > //So, I don?t know why the library is converting mass; I?ve tuned it to use boost::units::force_dimension/boost::units::length_dimension > > //I am doing something wrong where the library is not using force/length. > > //Below does work, mainly. > > //This is convert Si to SI and return value of 1.0 is correct. > > const auto t4 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::si::lineal_force_unit>>( > > 1.0 * boost::units::si::newton / boost::units::si::meter); > > //This convert lb/in to SI and return value is 175.1268369864 is correct. > > const auto t5 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::si::lineal_force_unit>>( > > 1.0 * boost::units::us::pound_force_base_unit::unit_type() / boost::units::us::inch_base_unit::unit_type()); > > //This converts lb/in to lb/in and return value is of 1.0 is correct. > > const auto t6 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::imperial::lineal_force_unit>>( > > 1.0 * boost::units::us::pound_force_base_unit::unit_type() / boost::units::us::inch_base_unit::unit_type()); > > //This is 2.205 and not correct. > > //It?s not converting SI-force/length to Imperial-force/length > > //Its converting Kg (mass) to lb (mass), 2.205 > > const auto t7 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::imperial::lineal_force_unit>>( > > 1.0 * boost::units::si::newton / boost::units::si::meter); > > //What have I done wrong? > > //Any help is appreciated. > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > https://lists.boost.org/mailman/listinfo.cgi/boost-users ------------------------------ Message: 2 Date: Wed, 21 Nov 2018 15:55:35 +1300 From: Gavin Lambert <boost(a)mirality.co.nz> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Program Options documentation is anaemic Message-ID: <3ab79a24-e6ff-e311-1d12-adbe5646a123(a)mirality.co.nz> Content-Type: text/plain; charset=utf-8; format=flowed On 20/11/2018 23:03, David Demelier wrote: > Reading the type_value documentation from Boost Program options feels like: > > ??? typed_value * composing(); > ??? Specifies that the value is composing. See the 'is_composing' > method for explanation. > > And the documentation of is_composing: > > ??? bool is_composing() const; > > Not sure if I know more what this function is supposed to do now. I agree that this seems somewhat unhelpful. FWIW a quick look elsewhere found https://www.boost.org/doc/libs/1_68_0/doc/html/program_options/tutorial.htm… which describes that option in more detail -- specifically that it's whether repeated parameters are merged or just replace the older value. > Also, I think this module/documentation should take a s/method/function/g. "Method" is the more common name for a method within a class. ------------------------------ Message: 3 Date: Tue, 20 Nov 2018 19:58:27 -0700 From: Steven Watanabe <watanabesj(a)gmail.com> To: Matt Vinson via Boost-users <boost-users(a)lists.boost.org> Cc: matt.vinson(a)sbcglobal.net Subject: Re: [Boost-users] boost::units - converting from one derived_dimension to another across systems (imperial to metric) Message-ID: <4f601999-f01c-0535-37a3-15e6e21d8331(a)gmail.com> Content-Type: text/plain; charset=utf-8 AMDG On 11/20/2018 06:46 PM, Matt Vinson via Boost-users wrote: > <snip> > <some reformatting to reduce line wrapping> > *.h----------------------------------------------------- > > namespace dimensional_analysis { > > ????typedef length_base_dimension::dimension_type length_dimension; > ????typedef mass_base_dimension::dimension_type mass_dimension; > > typedef make_system<inch_base_unit,pound_base_unit>::type ip_system; > This should be pound_force_base_unit. > ? namespace lineal_force { > ??? typedef mpl::divides<force_dimension,length_dimension>::type lineal_force_dimension;?????????? > > ??? namespace imperial { > > ????? //////////////// > ????? ////lb/in, right? > > ////boost::units::force_dimension =pound > ////boost::units::length_dimension = in > ????? //////////////// > ????? typedef unit<lineal_force_dimension,lengths::ip_system> lineal_force_unit; This unit is nonsensical because the ip_system as written is unable to represent the lineal_force_dimension. That this doesn't give a hard compiler error is a bug in the library. Once you fix ip_system, the conversions should be right. > ??? } > ??? namespace si { > ??? //////////////// > ??? ////N/m, right? > Yep. > ////boost::units::force_dimension = newton > ////boost::units::length_dimension = meter > ????? //////////////// > ????? typedef unit<lineal_force_dimension,si::system> lineal_force_unit; > ??? } > ? }//lineal_force > }//dimensional_analysis > > *.cpp----------------------------------------------------- > > //Imperiallb/in to SI N/m > The following conversion definitions are unnecessary and have no effect: > BOOST_UNITS_DEFINE_CONVERSION_FACTOR( > dimensional_analysis::lineal_force::imperial::lineal_force_unit, > dimensional_analysis::lineal_force::si::lineal_force_unit, > double, > 175.1268369864); // exact conversion > > BOOST_UNITS_DEFAULT_CONVERSION( > dimensional_analysis::lineal_force::imperial::lineal_force_unit, > dimensional_analysis::lineal_force::si::lineal_force_unit); > > //SI N/mto Imperial lb/in > > BOOST_UNITS_DEFINE_CONVERSION_FACTOR( > dimensional_analysis::lineal_force::si::lineal_force_unit, > dimensional_analysis::lineal_force::imperial::lineal_force_unit, > double, > 0.1837185501); // exact conversion > > BOOST_UNITS_DEFAULT_CONVERSION( > dimensional_analysis::lineal_force::si::lineal_force_unit, > dimensional_analysis::lineal_force::imperial::lineal_force_unit); > > <snip> > In Christ, Steven Watanabe ------------------------------ Message: 4 Date: Wed, 21 Nov 2018 04:09:11 +0100 From: Adam Wulkiewicz <adam.wulkiewicz(a)gmail.com> To: Zhang Qun <zhangq.rhy(a)gmail.com> Cc: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Enquiry on boost.geometry and intersection() Message-ID: <9d3e335d-df1a-7627-af4f-a9d3fd8c22ff(a)gmail.com> Content-Type: text/plain; charset="utf-8"; Format="flowed" Please do not top-post. Zhang Qun?wrote: > Hi Adam > I think I have figured it out. Because of the precision, the two > polygons are not the same. > > That also explains that why sometimes the intersection() gives me two > intersection points looking "exactly" the same but if you look at the > double precision, they are actually two different points. In reality, > these two points can be safely considered the same point. I can solve > this by comparing the two points distance. However, sometimes also > because of the precision, the intersection() does not even give me any > intersection points especially when the line is right across the > vertex of the polygon. How do I solve this kind of problem? Could you paste the WKTs of geometries (with sufficient precision) [1] and say what do you get and what do you expect? [1] e.g. std::cout << std::setprecision(20) << bg::wkt(polygon) << std::endl; Adam

2 1

Enquiry on boost.geometry and intersection()
by Zhang Qun 21 Nov '18

21 Nov '18

Hi guys, first-time post here. Hello to everyone. I'm using boost.geometry to implement a project. I need to calculate the intersection between a line and a polygon. I know there is no infinite line concept in boost.geometry. So I try to use the segment to intersect with a polygon, however, it seems not supported yet. Is there any other workaround that I can implement the intersection between a line and a polygon? The line is like y=mx+b or ax + by + c = 0. Thanks. Ethan

2 6

boost::units - converting from one derived_dimension to another across systems (imperial to metric)
by Matt Vinson 21 Nov '18

21 Nov '18

degski: I do not think am making the "nauseam" mistake. My issue is using Boost.Units correctly which I concede is difficult for me but I am reading the docs and trying to get it. In our field of engineering, we use Kg as a force; not a mass. (We also use pound as a force; not a mass - for your "UK's Weights and Measures Act 1963" counterpart). That said, I should not have made the mistake of using Kg as a force in Boost.Units, it's true. Shame on me. My task is to convert between lineal forces: k/ft, k/in, lb/ft, lb/in, kN/m, kN/cm, kN/m, N/m, N/cm, N/m, Metric ton/m, Metric ton/cm, Metric ton/mm, Kg/m, Kg/cm, Kg/mm. These are all force/length. Steven Watanabe: Thank you, again.#1: I was not trying to say it's wrong; sorry. Just that I did not see 'length' and opted for the one that did. The unit's are correct, as you say. #2: This is an error to start with Kg(force)/meter. I can start with N/meter. I've changed this variable name to newton_per_meter and the conversion factors. *.h----------------------------------------------------- namespace dimensional_analysis{ typedef boost::units::length_base_dimension::dimension_type length_dimension; typedef boost::units::mass_base_dimension::dimension_type mass_dimension; typedef boost::units::make_system<boost::units::us::inch_base_unit,boost::units::us::pound_base_unit>::type ip_system; namespace lineal_force { typedef boost::mpl::divides<boost::units::force_dimension,boost::units::length_dimension>::type lineal_force_dimension; namespace imperial { //////////////// ////lb/in, right? ////boost::units::force_dimension =pound ////boost::units::length_dimension = in //////////////// typedef boost::units::unit<lineal_force_dimension,lengths::ip_system> lineal_force_unit; } namespace si { //////////////// ////N/m, right? ////boost::units::force_dimension = newton ////boost::units::length_dimension = meter //////////////// typedef boost::units::unit<lineal_force_dimension,boost::units::si::system> lineal_force_unit; } }//lineal_force }//dimensional_analysis *.cpp----------------------------------------------------- //Imperiallb/in to SI N/m BOOST_UNITS_DEFINE_CONVERSION_FACTOR( dimensional_analysis::lineal_force::imperial::lineal_force_unit, dimensional_analysis::lineal_force::si::lineal_force_unit, double, 175.1268369864); // exact conversion BOOST_UNITS_DEFAULT_CONVERSION( dimensional_analysis::lineal_force::imperial::lineal_force_unit, dimensional_analysis::lineal_force::si::lineal_force_unit); //SI N/mto Imperial lb/in BOOST_UNITS_DEFINE_CONVERSION_FACTOR( dimensional_analysis::lineal_force::si::lineal_force_unit, dimensional_analysis::lineal_force::imperial::lineal_force_unit, double, 0.1837185501); // exact conversion BOOST_UNITS_DEFAULT_CONVERSION( dimensional_analysis::lineal_force::si::lineal_force_unit, dimensional_analysis::lineal_force::imperial::lineal_force_unit); //Imperialto SI. This should convert lb/in to N/m andreturn 175.1268369864(N/m) //But itdoes not. Its converting lb (mass) to Kg(mass), 0.454 const auto t2 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::si::lineal_force_unit>>( 1.0 *dimensional_analysis::lineal_force::imperial::lineal_force_unit::unit_type()); //Again, Imperial to SI. This should convert lb/in to N/m and return 175.1268369864 (N/m) //But itdoes not. It returns lb (mass) to Kg(mass) const auto t3 = boost::units::conversion_factor( dimensional_analysis::lineal_force::imperial::lineal_force_unit::unit_type(), dimensional_analysis::lineal_force::si::lineal_force_unit::unit_type()); //SI toImperial. This should convert N/m tolb/in and return 0.1837185501 (lb/in) //But itdoes not. Its converting Kg (mass) to lb(mass), 2.205 const auto t1 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::imperial::lineal_force_unit>>( 1.0 *dimensional_analysis::lineal_force::si::lineal_force_unit::unit_type()); //So, I don’t know whythe library is converting mass; I’ve tuned it to use boost::units::force_dimension/boost::units::length_dimension //I am doing something wrongwhere the library is not using force/length. //Below does work, mainly. //This isconvert Si to SI and return value of 1.0 is correct. const auto t4 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::si::lineal_force_unit>>( 1.0 *boost::units::si::newton / boost::units::si::meter); //This convert lb/in to SI and return value is 175.1268369864 is correct. const auto t5 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::si::lineal_force_unit>>( 1.0 * boost::units::us::pound_force_base_unit::unit_type() / boost::units::us::inch_base_unit::unit_type()); //This converts lb/in to lb/in and return value is of 1.0 is correct. const auto t6 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::imperial::lineal_force_unit>>( 1.0 * boost::units::us::pound_force_base_unit::unit_type() / boost::units::us::inch_base_unit::unit_type()); //This is2.205 and not correct. //It’s notconverting SI-force/length to Imperial-force/length //Itsconverting Kg (mass) to lb (mass), 2.205 const auto t7 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::imperial::lineal_force_unit>>( 1.0 * boost::units::si::newton /boost::units::si::meter); //What have I done wrong? //Any help is appreciated.

3 2

Program Options documentation is anaemic
by David Demelier 21 Nov '18

21 Nov '18

Hello, Reading the type_value documentation from Boost Program options feels like: typed_value * composing(); Specifies that the value is composing. See the 'is_composing' method for explanation. And the documentation of is_composing: bool is_composing() const; Not sure if I know more what this function is supposed to do now. Also, I think this module/documentation should take a s/method/function/g. What's your thoughts on this? Regards, -- David

2 1

[Spirit] uint_parser inconsistent results
by Michael Powell 20 Nov '18

20 Nov '18

Hello, I am trying to figure out why the uint_parser yields what looks like raw characters in one instance, yet in another instance yields the original given phrase. What do I mean by that? I have a string-literal rule, subset of the Google protobuf v2 grammar, and the octal-escaped rule yields a raw character, but the "same" hex-escaped rule yields the given input string. Both rules are of type qi::rule<It, char()>. And the str_lit rule is qi::rule<It, std::string()>, basically. oct_esc %= '\\' >> uint_parser<unsigned char, 8, 3, 3>{}; hex_esc %= no_case["\\x"] >> uint_parser<unsigned char, 16, 2, 2>{}; char_val %= hex_esc | oct_esc | char_esc | ~char_("\0\n\\"); str_lit %= ("'" >> *(char_val - "'") >> "'") | ('"' >> *(char_val - '"') >> '"') ; struct escapes_t : qi::symbols<char, char> { escapes_t() { this->add("\\a", '\a') ("\\b", '\b') ("\\f", '\f') ("\\n", '\n') ("\\r", '\r') ("\\t", '\t') ("\\v", '\v') ("\\\\", '\\') ("\\'", '\'') ("\\\"", '"') ; } } char_esc; The only thing I can figure is that perhaps it has something to do with no-case having a secondary effect on the rule? I do not care which way it lands, per se, in either raw or original string, although landing in the raw, that is, unescaped, has some advantages, I suppose. However, it is a mystery to me how there are two different outcomes. Any thoughts? Suggestions? Thanks! Michael Powell

1 1

questions about visibility/dlls under mingw
by Robert Ramey 20 Nov '18

20 Nov '18

MINGW is the platform which runs gcc compilers under winsoze. I include all the visibility attribute in the "right" places with serialization build and tests. This is looking like it's passing on all platforms EXCEPT MINGW. I think MINGW uses the windows attributes, but I'm wonder if our boost setup uses the gcc macros. This would explain the bahavior I'm getting now. But honestly I really have no idea. here's the link to the appveyor results: https://ci.appveyor.com/project/RobertRamey/serialization/builds/20309631 Perhaps this is a config issue? or I'm doing wrong? I'm loath to much with this just for this one platform. Robert Ramey

3 12

Fwd: Boost::Filesystem - How to iterate, through the whole drive
by Richard Závodný 20 Nov '18

20 Nov '18

---------- Forwarded message --------- From: Richard Závodný <zavodnyrichard(a)gmail.com> Date: Sat, Nov 17, 2018, 3:59 PM Subject: Boost::Filesystem - How to iterate, through the whole drive To: <boost-users(a)lists.boost.org> Hey guys, I need iterate over all directories from starting path. If I start iterating from C:\some-dir it works very well, however if I try to iterate from C:\, it doesn't work. How can iterate through the whole drive? Thank you. Code is here: https://pastebin.com/mpsKJxH2 <https://pastebin.com/3J6FEMG5>. The problem I experience is commented right in the code section (line 1, 13 and 25).

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boost::units - converting from one derived_dimension to another across systems (imperial to metric)
by Matt Vinson 20 Nov '18

20 Nov '18

Eisuke Kawashima: Thank You. I'll have a look. When I saw Boost.Units did not have imperial and we had to create it ourselves, I thought: the US is s 5 trillion dollar market, most of those markets need programming, all are on imperial. Boost.Units needs imperial and programmers would find and use it. Steven Watanabe: Thank You. This solution doesn't seem correct as it does not consider "length".... boost::units::derived_dimension< boost::units::mass_base_dimension, 1, boost::units::time_base_dimension, -2>::typeI thought I'd at it (L M T^-2 L-1) but this didn't do well.: typedef boost::units::derived_dimension< boost::units::length_base_dimension, 1, boost::units::mass_base_dimension, 1, boost::units::time_base_dimension, -2, boost::units::length_base_dimension, -1 >::type lineal_force_dimension; So, I tried the " typedef boost::mpl::divides<...>" solution as it has force and length. I am closer, I hope. *.h------------------------------------------------------------------------------------------------------------------------------------------ namespace dimensional_analysis { typedef boost::units::length_base_dimension::dimension_type length_dimension; typedef boost::units::mass_base_dimension::dimension_type mass_dimension; typedef boost::units::make_system< boost::units::us::inch_base_unit, boost::units::us::pound_base_unit >::type ip_system; namespace lineal_force { typedef boost::mpl::divides< boost::units::force_dimension, boost::units::length_dimension>::type lineal_force_dimension; namespace imperial { typedef boost::units::unit< lineal_force_dimension, dimensional_analysis ::ip_system > lineal_force_unit; typedef boost::units::quantity<lineal_force_unit, double> pound_per_in_quantity; BOOST_UNITS_STATIC_CONSTANT(pound_per_inch, pound_per_in_quantity); } namespace si { typedef boost::units::unit< lineal_force_dimension, boost::units::si::system > lineal_force_unit; typedef boost::units::quantity<lineal_force_dimension, double> kg_per_meter_quantity; BOOST_UNITS_STATIC_CONSTANT(kg_per_meter, kg_per_meter_quantity); } }//lineal_force }//dimensional_analysis *.cpp------------------------------------------------------------------------------------------------------------------------------------------ BOOST_UNITS_DEFINE_CONVERSION_FACTOR(dimensional_analysis::lineal_force::imperial::lineal_force_unit, dimensional_analysis::lineal_force::si::lineal_force_unit, double, 17.858); // exact conversion BOOST_UNITS_DEFAULT_CONVERSION(dimensional_analysis::lineal_force::imperial::lineal_force_unit, dimensional_analysis::lineal_force::si::lineal_force_unit); BOOST_UNITS_DEFINE_CONVERSION_FACTOR(dimensional_analysis::lineal_force::si::lineal_force_unit, dimensional_analysis::lineal_force::imperial::lineal_force_unit, double, 0.0559974); // exact conversion BOOST_UNITS_DEFAULT_CONVERSION(dimensional_analysis::lineal_force::si::lineal_force_unit, dimensional_analysis::lineal_force::imperial::lineal_force_unit); //This is not converting force/length and is converting si -> imperial mass (only) = 110.2. Needs to consider force/length, =50*0.0559974 auto t1 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::imperial::lineal_force_unit>>( 50.0 * dimensional_analysis::lineal_force::si::lineal_force_unit::unit_type()); / This is not converting force/length and i sconverting imperial -> si mass (only) = 22.7. Needs to consider force/length, =50*17.858 auto t2 = static_cast<boost::units::quantity<dimensional_analysis::lineal_force::si::lineal_force_unit>>( 50.0 * dimensional_analysis::lineal_force::imperial::lineal_force_unit::unit_type()); //This is again only converting mass and needs to convert force/length const auto t3 = boost::units::conversion_factor( dimensional_analysis::lineal_force::imperial::lineal_force_unit::unit_type(), dimensional_analysis::lineal_force::si::lineal_force_unit::unit_type()); On Monday, November 19, 2018, 12:46:57 PM CST, boost-users-request(a)lists.boost.org <boost-users-request(a)lists.boost.org> wrote: Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. Re: boost::units - converting from one derived_dimension to another across systems (imperial to metric) (Eisuke Kawashima) 2. Re: Fwd: Boost::Filesystem - How to iterate, through the whole drive (Richard Z?vodn?) 3. Re: boost::units - converting from one derived_dimension to another across systems (imperial to metric) (Steven Watanabe) 4. Re: [release] Boost 1.69.0 Beta 1 (Marshall Clow) ---------------------------------------------------------------------- Message: 1 Date: Tue, 20 Nov 2018 02:23:10 +0900 From: Eisuke Kawashima <e.kawaschima+boost(a)gmail.com> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] boost::units - converting from one derived_dimension to another across systems (imperial to metric) Message-ID: <CAHhxtD6A9Jwhv5amKnTa1bmNkD0U4_LGre8ySKFfQXK7w62oEQ(a)mail.gmail.com> Content-Type: text/plain; charset="UTF-8" Hi list, > I am having trouble converting from one derived_dimension to another across systems (imperial to metric). I'd like to convert, say, lb/in to, say, kg/m. I thought I would do the following but get a compiler error #: > > *.h-------------------------------------------------------------------------------- > namespace dimensional_analysis { > namespace lineal_force { > //lb/in > typedef boost::units::derived_dimension< > boost::units::us::pound_force_base_unit, 1, > boost::units::us::inch_base_unit, -1 > >::type lb_per_inch_dimension; > typedef boost::units::unit< > lb_per_inch_dimension, > dimensional_analysis::lengths::ip_system > > lb_per_inch_unit; > typedef boost::units::quantity<lb_per_inch_unit, double> lb_per_inch_quantity; > BOOST_UNITS_STATIC_CONSTANT(lbpin, lb_per_inch_quantity); > //kg/m > typedef boost::units::derived_dimension< > boost::units::si::kilogram_base_unit, 1, > boost::units::si::meter_base_unit, -1 > >::type kg_per_meter_dimension; > typedef boost::units::unit< > kg_per_meter_dimension, > boost::units::si::system > > kg_per_meter_unit; > typedef boost::units::quantity<kg_per_meter_unit, double> kg_per_meter_unit_quantity; > BOOST_UNITS_STATIC_CONSTANT(kgpm, kg_per_meter_unit_quantity); > }//lineal_force > }//dimensional_analysis > > *.cp ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- > //Do I need these? > BOOST_UNITS_DEFINE_CONVERSION_FACTOR(dimensional_analysis::lineal_force::kg_per_meter_unit, dimensional_analysis::lineal_force::lb_per_inch_unit, double, 0.0559974); // exact conversion > BOOST_UNITS_DEFAULT_CONVERSION(dimensional_analysis::lineal_force::kg_per_meter_unit, dimensional_analysis::lineal_force::lb_per_inch_unit); > > //This does not compile# > const auto conv_factor_try0 = conversion_factor(dimensional_analysis::lineal_force::kg_per_meter_unit::unit_type(), dimensional_analysis::lineal_force::lb_per_inch_unit::unit_type()); > > # *\boost_1_68_0\boost\units\detail\conversion_impl.hpp(340): error C2672: 'conversion_factor': no matching overloaded function found (compiling source file...*.cpp) > > Any help is appreciated I opened a PR (https://github.com/boostorg/units/pull/32) to address such a situation; the following code ```cpp #include <iostream> #include <boost/units/base_units/us/inch.hpp> #include <boost/units/base_units/us/pound_force.hpp> #include <boost/units/io.hpp> #include <boost/units/physical_dimensions.hpp> #include <boost/units/systems/si.hpp> int main() { auto force_us{1.0 * boost::units::us::pound_force}; auto length_us{1.0 * boost::units::us::inch}; boost::units::quantity<boost::units::si::force, double> force_si{force_us}; boost::units::quantity<boost::units::si::length, double> length_si{length_us}; std::cout << force_us << " = " << force_si << '\n'; std::cout << length_us << " = " << length_si << '\n'; std::cout << force_us / length_us << " = " << force_si / length_si << '\n'; return 0; } ``` will print ``` 1 lbf = 4.44822 m kg s^-2 1 in = 0.0254 m 1 lbf in^-1 = 175.127 kg s^-2 ``` Best -- Eisuke Kawashima ------------------------------ Message: 2 Date: Mon, 19 Nov 2018 19:24:58 +0100 From: Richard Z?vodn? <zavodnyrichard(a)gmail.com> To: degski <degski(a)gmail.com>, boost-users(a)lists.boost.org Subject: Re: [Boost-users] Fwd: Boost::Filesystem - How to iterate, through the whole drive Message-ID: <d13622b0-9a68-d109-c26e-b60e3a5c45c8(a)gmail.com> Content-Type: text/plain; charset="utf-8"; Format="flowed" I just wanna try it again here, maybe somebody will shop up who knows where is the problem as I unfortunately couldn't fix it with degski (but still, thank you for your time :)). His example (can be found below) doesn't work on my system. The problem is I can't start iteration from the drive root (for example E:\), because it will iterate only the directory above (E:\projects\boost\build) the directory that the executable is located in (the executable is located in E:\projects\boost\build\Debug). What is weird that if I move the executable to the different directory (let's say C:\Users\USER_NAME\Downloads) it will still iterate only the build directory. I tried to play with Visual Studio -> PROJECT_NAME -> Properties -> Debugging -> Working Directory, but without a success. According to degski he has the value of this entry set to $(ProjectDir) which is the same value as mine. Thank you. On 11/18/2018 9:04 AM, degski wrote: > On Sun, 18 Nov 2018 at 05:31, Richard Z?vodn? via Boost-users > <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org>> wrote: > > > > ---------- Forwarded message --------- > From: *Richard Z?vodn?* <zavodnyrichard(a)gmail.com > <mailto:zavodnyrichard@gmail.com>> > Date: Sat, Nov 17, 2018, 3:59 PM > Subject: Boost::Filesystem - How to iterate, through the whole drive > To: <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org>> > > > Hey guys, I need iterate over all directories from starting path. > If I start iterating from C:\some-dir it works very well, however > if I try to iterate from C:\, it doesn't work. How can iterate > through the whole drive? Thank you. > > > Code is here: https://pastebin.com/mpsKJxH2 > <https://pastebin.com/3J6FEMG5>. The problem I experience is > commented right in the code section (line 1, 13 and 25). > > > This works for me, either with boost-1.68 (not that I think that > matters) or the STL-VC-15.9.1 (/std:c++17): > > #include <iostream> > #include <boost/filesystem.hpp> > > namespace fs = boost::filesystem; > > int main ( ) { > ??? for ( auto & p : fs::recursive_directory_iterator ( "d:\\" ) ) { > ??????? std::cout << p.path ( ) << '\n'; > ??? } > } > > Note that: "The iteration order is unspecified, except that each > directory entry is visited only once." > > degski > -- > /*/*?*/If something cannot go on forever, it will stop" - Herbert Stein*/

4 6

Making an ASIO asynchronous operation from flock()
by Cristian Morales Vega 20 Nov '18

20 Nov '18

So I need to flock (http://man7.org/linux/man-pages/man2/flock.2.html) something (pre-existing flock in other piece of software to interoperate with) and I though: "I think I'm actually starting to understand ASIO, let's make a proper ASIO asynchronous operation with flock". Long story short, I now know better: I will never get ASIO. So my main issues are with the background thread. According to https://www.boost.org/doc/libs/develop/doc/html/boost_asio/overview/core/th… "the threads ... must block all signals". OK, it makes sense, but... - I can make pthread_sigmask() the first thing once the std::thread starts executing. But, I can't really guarantee the thread will never receive a signal, can I? There is a small amount of time between the thread starting to be able to receive signals and pthread_sigmask() doing its job. Modifying the signal mask before the background thread is created (so also from the "not-background" thread) doesn't seem a lot better. - How do I cancel the asynchronous operation? flock() is blocking, not a lot I can do to unblock it. I could send a signal to the background thread, but... they must be blocked, so no. I can't join the thread while it's blocked in flock(). So... should it be detached? I could then maybe just destroy the std::thread, but I still need to call the handler with boost::asio::error::operation_aborted... So, my question: I'm making it more difficult than it is? There is some pattern I should be following which makes all this simple? See what I have below (sorry for the camel case) ------------------------------------------------------------------------------- #include <boost/asio.hpp> #include <boost/beast/core/bind_handler.hpp> #include <boost/system/error_code.hpp> #include <boost/system/system_error.hpp> #include <fcntl.h> #include <iostream> #include <sys/file.h> #include <sys/stat.h> #include <sys/types.h> #include <thread> namespace asio = boost::asio; using error_code = boost::system::error_code; using system_error = boost::system::system_error; class FLockablePosixDescriptor : public asio::posix::descriptor { public: enum class FlockType : int { SHARED = LOCK_SH, EXCLUSIVE = LOCK_EX }; using asio::posix::descriptor::descriptor; FLockablePosixDescriptor(FLockablePosixDescriptor &&) = default; FLockablePosixDescriptor &operator=(FLockablePosixDescriptor &&) = default; ~FLockablePosixDescriptor(); template <typename FLockToken> BOOST_ASIO_INITFN_RESULT_TYPE(FLockToken, void(error_code)) asyncFLock(FlockType type, FLockToken &&token); void cancel(); void cancel(error_code &ec); private: template <typename FLockHandler> void doFLock(int fd, FlockType type, FLockHandler &handler); asio::io_context mBackgroundContext{1}; std::thread mThread; }; FLockablePosixDescriptor::~FLockablePosixDescriptor() { mBackgroundContext.stop(); mThread.join(); } template <typename FLockToken> BOOST_ASIO_INITFN_RESULT_TYPE(FLockToken, void(error_code)) FLockablePosixDescriptor::asyncFLock(FlockType type, FLockToken &&token) { asio::async_completion<FLockToken, void(error_code)> init(token); mBackgroundContext.post([this, fd = native_handle(), type, handler = std::move(init.completion_handler), work = asio::make_work_guard(get_executor())] { doFLock(fd, type, handler); }); mThread = std::thread([this] { mBackgroundContext.run(); }); return init.result.get(); } template <typename FLockHandler> void FLockablePosixDescriptor::doFLock(int fd, FlockType type, FLockHandler &handler) { error_code ec; if (flock(fd, static_cast<int>(type)) == -1) { ec = error_code(errno, boost::system::system_category()); } asio::post(get_executor(), boost::beast::bind_handler(handler, ec)); } void FLockablePosixDescriptor::cancel() { error_code ec; cancel(ec); if (ec) { throw system_error(ec, "cancel"); } } void FLockablePosixDescriptor::cancel(error_code &ec) { // TODO: Cancel flock asio::posix::descriptor::cancel(ec); } int main() { boost::asio::io_context ioc; int fd = open("l", O_RDONLY); FLockablePosixDescriptor desc(ioc, fd); desc.asyncFLock(FLockablePosixDescriptor::FlockType::SHARED, [](const error_code &ec) { std::clog << "Done " << ec << std::endl; }); ioc.run(); } -------------------------------------------------------------------------------

2 2

[release] Boost 1.69.0 Beta 1
by Marshall Clow 19 Nov '18

19 Nov '18

Boost release 1.69.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta1/source/> The SHA256 checksums are as follows: ee0ecd7d31f58474c1e0210089c9e66bd878d4d1e7436ac511e359aa4a9d3e86 ./boost_1_69_0_b1.7z 3e25c46f2171799caabbeb419ba7859fffb62208f3a1c80798713377ab07af0e ./boost_1_69_0_b1.tar.bz2 71f4b57175058af1b8c320971cf29226e5a652931a679f7e1c086655147ecafb ./boost_1_69_0_b1.tar.gz ec9ef7d2c9f0d41f560769e67bc7ff207cc999243a7dd6c3f6bcfbdbf0827a7b ./boost_1_69_0_b1.zip For details of what's in the release, see < https://www.boost.org/users/history/version_1_69_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

3 4

boost::units - converting from one derived_dimension to another across systems (imperial to metric)
by Matt Vinson 19 Nov '18

19 Nov '18

Thanks for input...Ok, I have errors creating a 'lineal force unit'. In our branch of engineering, we have kips****/ft, kips/in, lbs/foot, lbs/in, kN/meter, Kn/cm, KN/mm, N/meter, N/cm, N/mm, Metric Ton/meter, Metric Ton/cm, Metric Ton/mm, KiloGram/meter $, KiloGram/cm, KiloGram/mm, etc....All these units* are loosing force divided by length. After all the appreciated input in this thread, I thought I'd try this but it does not compile*** probably because force is "L M T^-2" and length is "L" which is not correct: //Lineal Force typedef boost::units::derived_dimension< boost::units::force_dimension, 1, boost::units::length_dimension, -1 >::type lineal_force_dimension; How can I use Boost.Units to convert one force/length to another force/length: say, lb/in to, say, kg/m? *not Boost.Units**, the units in the engineering math equation**A set of base units raised to rational exponents, e.g. m^1, kg^1, m^1/s^2. *** ...\boost_1_68_0\boost\mpl\aux_\preprocessed\plain\less.hpp(20): error C2039: 'value': is not a member of 'boost::units::detail::dimension_list_tag' ****1000 lbs force = kips***** Here is a table in Wiki about converting between lbs and kilogram. Kilogram in Boost.Units is a mass not a force so I need to create a kilogram force and I did that when I converted "Forces" $ in another task... $.h struct metric_ton_base_unit : boost::units::base_unit<metric_ton_base_unit, boost::units::force_dimension, 7> { }; typedef metric_ton_base_unit::unit_type metric_ton_unit; BOOST_UNITS_STATIC_CONSTANT(metric_ton, metric_ton_unit); typedef boost::units::quantity<metric_ton_unit> metric_ton_quantity; // typedef boost::units::make_scaled_unit<metric_ton_unit, boost::units::scale<10, boost::units::static_rational<-3>>>::type kg_force_unit; BOOST_UNITS_STATIC_CONSTANT(kg_force, kg_force_unit); typedef boost::units::quantity<kg_force_unit> kg_quantity;.cpp BOOST_UNITS_DEFINE_CONVERSION_FACTOR(dimensional_analysis::force::metric_ton_base_unit, dimensional_analysis::force::newton_base_unit, double, 9806.65); // exact conversion BOOST_UNITS_DEFAULT_CONVERSION(dimensional_analysis::force::metric_ton_base_unit, dimensional_analysis::force::newton_base_unit);% $ lb/in to kg/m: Google: convert lb/in to kg/m

2 1

boost::units - converting from one derived_dimension to another across systems (imperial to metric)
by Matt Vinson 19 Nov '18

19 Nov '18

I am having trouble converting from one derived_dimension to another across systems (imperial to metric). I'd like to convert, say, lb/in to, say, kg/m. I thought I would do the following but get a compiler error #: *.h-------------------------------------------------------------------------------- namespace dimensional_analysis { namespace lineal_force { //lb/in typedef boost::units::derived_dimension< boost::units::us::pound_force_base_unit, 1, boost::units::us::inch_base_unit, -1 >::type lb_per_inch_dimension; typedef boost::units::unit< lb_per_inch_dimension, dimensional_analysis::lengths::ip_system > lb_per_inch_unit; typedef boost::units::quantity<lb_per_inch_unit, double> lb_per_inch_quantity; BOOST_UNITS_STATIC_CONSTANT(lbpin, lb_per_inch_quantity); //kg/m typedef boost::units::derived_dimension< boost::units::si::kilogram_base_unit, 1, boost::units::si::meter_base_unit, -1 >::type kg_per_meter_dimension; typedef boost::units::unit< kg_per_meter_dimension, boost::units::si::system > kg_per_meter_unit; typedef boost::units::quantity<kg_per_meter_unit, double> kg_per_meter_unit_quantity; BOOST_UNITS_STATIC_CONSTANT(kgpm, kg_per_meter_unit_quantity); }//lineal_force }//dimensional_analysis *.cp ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- //Do I need these? BOOST_UNITS_DEFINE_CONVERSION_FACTOR(dimensional_analysis::lineal_force::kg_per_meter_unit, dimensional_analysis::lineal_force::lb_per_inch_unit, double, 0.0559974); // exact conversion BOOST_UNITS_DEFAULT_CONVERSION(dimensional_analysis::lineal_force::kg_per_meter_unit, dimensional_analysis::lineal_force::lb_per_inch_unit); //This does not compile# const auto conv_factor_try0 = conversion_factor(dimensional_analysis::lineal_force::kg_per_meter_unit::unit_type(), dimensional_analysis::lineal_force::lb_per_inch_unit::unit_type()); # *\boost_1_68_0\boost\units\detail\conversion_impl.hpp(340): error C2672: 'conversion_factor': no matching overloaded function found (compiling source file...*.cpp) Any help is appreciated

8 8

Bad link in https://www.boost.org/community/groups.html page
by Dan Field 19 Nov '18

19 Nov '18

The https://www.boost.org/community/groups.html page discusses various boost mailing lists. In the section discussing the Users mailing list, there's a link to browse Gmain's searchable archive. This link is dead.

1 0

Broken link in Getting Started Page
by David Demelier 19 Nov '18

19 Nov '18

Hello, The link: (an up-to-date list is always available in the Boost.Build documentation). In the getting started page is broken and ends in 404. https://www.boost.org/doc/libs/1_68_0/more/getting_started/windows.html Regards,

1 0

[Variant] Bug assigning similar, but different concrete types during assignment / ctor relay
by Michael Powell 18 Nov '18

18 Nov '18

Hello, I've got a Boost.Variant confusion going on during ctor relay. I have two types participating in the Variant, an Integer type and a Floating Point type. Both are Numeric as a base class. i.e. something like: template<typename T> struct numeric {}; struct integer : numeric<long> {}; struct floating_point : numeric<double> {}; Then: using constant_value = boost::variant<..., floating_point, integer, ...>; Somewhere during the handling, I have a test case in which I have a constant_value{} starting out in life as an integer{}. However, somewhere during handling, variant is misinterpreting integer (which=3) as a floating_point (which=2). This is incorrect, of course. I could force the issue, I suppose and re-set the value to the integer, but I'd like to understand the issue. I think it's a bug in variant, or perhaps a "feature" confusing integer with floating_point along base class numeric lines? Any ideas

2 5

[release] Boost 1.69.0 Beta 1 Release Candidate 3
by Marshall Clow 17 Nov '18

17 Nov '18

[ Ok, I've rebuilt the RC - and it contains only the changes to function and MPL ] The release candidates for the third 1.69.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta1.rc3/source/> The release notes are not yet final. The SHA256 checksums are as follows: ee0ecd7d31f58474c1e0210089c9e66bd878d4d1e7436ac511e359aa4a9d3e86 ./boost_1_69_0_b1_rc3.7z 3e25c46f2171799caabbeb419ba7859fffb62208f3a1c80798713377ab07af0e ./boost_1_69_0_b1_rc3.tar.bz2 71f4b57175058af1b8c320971cf29226e5a652931a679f7e1c086655147ecafb ./boost_1_69_0_b1_rc3.tar.gz ec9ef7d2c9f0d41f560769e67bc7ff207cc999243a7dd6c3f6bcfbdbf0827a7b ./boost_1_69_0_b1_rc3.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

2 2

Re: [Boost-users] [boost] [release] Boost 1.69.0 Beta 1 Release Candidate 2
by Marshall Clow 16 Nov '18

16 Nov '18

On Thu, Nov 15, 2018 at 11:37 AM Robert Ramey via Boost < boost(a)lists.boost.org> wrote: > On 11/14/18 2:50 PM, Marshall Clow via Boost wrote: > > Marshall, > > I would like to merge development of the serialization library into the > master if there is an opportunity to do so. If not, I'll just wait > until after the release. > After the beta release, sure. > I know you've complained about merging w/o permission. I'm not a git > guru but can't you tag the current state and work with that > independently of what anyone subsequently merges. Also there's creating > a branch for the merge. Also the possibility of keeping the release > candidate on your own machine and only pulling what you want to > explictly merge. Just food for thought? > Or you can merge to release locally and not push those changes until later. -- Marshall

2 1

process group object creation fail with version-1.67, 1.68
by dinesh kumar 16 Nov '18

16 Nov '18

Hi Team, I would like to take this to your notice, as the boost process group object creation is failing, in windows with ${SUBJECT} versions. I've tried 1.66, 1.69-b1-canadiate2 both are working fine. #include <boost/process.hpp> #include <iostream> int main() { try { boost::process::group grp; } catch (std::exception &e) { std::cout << e.what(); } return 0; } *Output* SetInformationJobObject() failed: The handle is invalid. Visual studio version is: 15.8.5 -- Regards, Dinesh manojadinesh.blogspot.com

1 0

[release] Boost 1.69.0 Beta 1 Release Candidate 2
by Marshall Clow 16 Nov '18

16 Nov '18

The release candidates for the second 1.69.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta1.rc2/source/> The release notes are not yet final. The SHA256 checksums are as follows: 77827b25121159a4e65cfbdf19713e2d589fce267fd6f08615a453d24753c9d3 ./boost_1_69_0_b1_rc2.7z ea05c6e01c856369afdab1f6c075e06fb0f965ab1c247f753ed5c951a9db4e71 ./boost_1_69_0_b1_rc2.tar.bz2 b393a73cf084be716c40ef346cfacb1c95e7b14637e8385eeeb50774dd0b99ed ./boost_1_69_0_b1_rc2.tar.gz 74c0c0a19a700fee2b4f434bb7df50840642e3c35924e85864b278bd519af062 ./boost_1_69_0_b1_rc2.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

2 5

[Optional] Lazy initialized optional
by Michael Powell 14 Nov '18

14 Nov '18

Hello, I am looking into deriving from boost::optional and adding lazy initialization capability. I can arrange a constructor, or whatever, to inject an appropriate factory method, functional callback, etc, that's no problem. >From the boost::optional perspective, I'd like to override a key method (or methods, hopefully not too many) in order to inject that factory provided value. I'm thinking optional::get? Unless there's a better override for that? Cheers, Michael Powell

3 3

[release] Boost 1.69.0 Beta 1 Release Candidate 1
by Marshall Clow 14 Nov '18

14 Nov '18

The release candidates for the first 1.69.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta.1.rc1/source/> The release notes are not yet available. The updated documentation is not yet available. [ They will be available in a day or two. ] The SHA256 checksums are as follows: db6b346389714647490d6503db881e4178dd8cd498f850999bebf72cacd4c4ed boost_1_69_0_b1_rc1.7z d128c82351becbd37a02b9b4818994d3f66ff8bdbc0a18838206f4c070db97af boost_1_69_0_b1_rc1.tar.bz2 4df6262db53cfd0d0f934cb126f7e48e94872fe4441cbac6bf72a43bfb136a45 boost_1_69_0_b1_rc1.tar.gz e2908e33cc15f92cda06ddde6a3da43b18967a83105355571fc3cf6e75820c7f boost_1_69_0_b1_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Boost Release Managers

7 16

Trouble building boost
by Vipin Verma 13 Nov '18

13 Nov '18

Hello I have tried building boost on my Windows as well as Ubuntu system, but I am not able to make it work. Could you please help me? Here is a post with details about Windows - https://stackoverflow.com/questions/53273860/opennero-windows-could-not-fin… Here is a post about Ubuntu - https://stackoverflow.com/questions/53151130/opennero-ubuntu-process-finish… -- Regards Vipin Verma <https://www.linkedin.com/in/vipin8169> BlueSapling Technologies Pvt Ltd. <https://bluesapling.com/> +1-480-410-1673

1 0

[Variant] Minimum implementation to be variant friendly
by Michael Powell 13 Nov '18

13 Nov '18

Hello, What's the minimum implementation a struct needs to fulfill in order to be boost::variant friendly? Things like, does it need to support perfect forwarding? An assignment operator? And so on. Thanks! Michael Powell

3 4

[Spirit] Qi int_parser rejecting a negative signed std::intmax_t
by Michael Powell 12 Nov '18

12 Nov '18

Hello, qi::int_parser works fine for a positive signed hex radix integer, but is failing for a negative signed hex radix integer. My integer type is std::intmax_t, which on this platform I think is long long. Is there an integer width constraint? And/or a signage problem? Do I need to enable BOOST_HAS_LONG_LONG? Or is that enabled by default? Cheers, thanks! Michael Powell

2 7

Boost 1.68.0 contains only python 3.7 library, no python 2.7 library?
by Heng Zhou 10 Nov '18

10 Nov '18

Hi, I installed Boost 1.68.0 recently from Windows x64 pre-compiled binary "boost_1_68_0-msvc-14.0-64.exe" downloaded from https://urldefense.proofpoint.com/v2/url?u=https-3A__sourceforge.net_projec…. Then, I noticed that this version of Boost contains only python 3.7 library because the filenames under C:\local\boost_1_68_0\lib64-msvc-14.0 are only boost_python37-vc140-mt-.... This caused errors from building a third-party library which tries to link Boost python 2.7 library (i.e., tries to find file boost_python27-vc140-mt-...) . So what is matter? Does Boost decide to stop supporting python 2.7 since version 1.68.0, or is Boost python 2.7 library located somewhere else using some hard-to-recognize filename? I'm using Windows 10, VS2015 and have only python 2.7 installed. Thank you for your help with this issue.

2 1

[Format] Possible to format numeric values using radix?
by Michael Powell 09 Nov '18

09 Nov '18

Hello, For instance, given a numerical value, I'd like to specify the Radix, whether to format octal or hex. Thanks in advance! Best regards, Michael Powell

1 1

[DLL] BOOST_DLL_ALIAS not working on MinGW-w64
by David Demelier 09 Nov '18

09 Nov '18

Hello, I'm using boost 1.68 on MinGW-w64 (Windows 10). I'm trying a simple plugin that works fine under Linux and FreeBSD However, on Windows boost::dll::import_alias triggers an exception: terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::system::system_error> >' what(): boost::dll::shared_library::get() failed: The specified procedure could not be found This is the plugin (plugin.cpp) #include <iostream> #include <boost/dll.hpp> namespace custom { void my_function() { puts("CALLED"); } } // !custom BOOST_DLL_ALIAS(custom::my_function, my_function) I compile using: g++ -std=c++17 -shared -o plugin.dll plugin.cpp -lboost_system-mt And the simple main.cpp file: #include <boost/dll.hpp> int main() { using my_function = void (); auto f = boost::dll::import_alias<my_function>("./plugin.dll", "my_function"); } What's strange, nm does not report any kind of unmangled symbols related to "my_function": $ nm plugin.dll | grep my_function 0000000067e81422 t _GLOBAL__sub_I__ZN6custom11my_functionEv 0000000067e813b0 T _ZN6custom11my_functionEv It should contains something starting with boostdll_ isn't it? What's happening there? Do I miss something? -- David

1 0

[Spirit] Qi lexeme only taking the first word
by Michael Powell 08 Nov '18

08 Nov '18

Hello, I've got a couple of rules that are perplexing to me. First, rule<It, std::string(), St> id %= lexeme[qi::alpha >> *char_("A-Za-z0-9_")]; In and of itself, id is working fine. Then I've got a "full id": rule<It, full_id_t(), St> full_id %= id >> *(char_('.') >> id); Where: struct full_id_t { std::string val; }; full_id_t::val is quite intentional for reasons elsewhere in the grammar. The perplexity comes in, it seems lexeme is only shaving off the first word as the val. For instance, parsing "two.oranges.red.test", I receive back "two" in the AST. Perhaps I should defer specifying the lexeme part of id until later? Thoughts? Suggestions? Thank you! Best regards, Michael Powell

4 12

Build/use Boost without ICU
by braden 08 Nov '18

08 Nov '18

How does one build (and use) Boost without ICU when ICU is installed (i.e., visible to b2)? I am am bootstrapping with: ...which shows: Seems reasonable so far. Building happens with: ...which shows: In spite of passing "--disable-icu -sboost.locale.icu=off" to b2, I still see Boost.Locale getting built with -DBOOST_LOCALE_WITH_ICU=1; e.g.: What's the correct way to do this? ----- Braden McDaniel braden(a)endoframe.com -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

3 3

Newby help with Boost::Log
by Davies, John 08 Nov '18

08 Nov '18

I'm using Boost Log to capture all keypresses in my embedded device. I want to be able to store at most 3 files of a certain size and rotate them. That's working. My problem is a scenario like this: The device is inserting data into Log_009.log which is in the base folder. In the log folder are Log_006.log, Log_007.log, and Log_008.log. The program stops and restarts. This may be due to some keypress that was logged in Log_009.log. When it restarts, it clears out Log_009.log and starts it over - losing the last logged keypresses Ideally, I'd like Boost Log to just keep appending to Log_009.log, but my reading online says that this isn't possible. My second favorite solution would be that Log_009 gets rotated and Log_010.log is started. Anything so I don't lose data. Here is my configuration: logging::add_common_attributes(); logging::add_file_log ( keywords::file_name = "KeyLog_%3N.log", keywords::target = "./Logs", keywords::rotation_size = 500, // 10 * 1024 * 1024, keywords::format = "[%TimeStamp%]: %Message%", keywords::auto_flush = true, keywords::min_free_space = 30 * 1024 * 1024, boost::log::keywords::max_size = 20 * 1024, keywords::enable_final_rotation = true, keywords::scan_method = sinks::file::scan_matching, keywords::max_files = 3 ); Can you see what I'm missing? If a program exits via a crash, does final rotation occur? Maybe I need something like enable_initial_rotation. Thanks for the help, John ________________________________ The information contained in this message may be confidential and legally protected under applicable law. The message is intended solely for the addressee(s). If you are not the intended recipient, you are hereby notified that any use, forwarding, dissemination, or reproduction of this message is strictly prohibited and may be unlawful. If you are not the intended recipient, please contact the sender by return e-mail and destroy all copies of the original message.

1 0

Deadline for 1.69.0 beta extended
by Marshall Clow 07 Nov '18

07 Nov '18

The deadline for closing the master branch for the 1.69.0 beta has been extended until Friday, November 9th. The final release date has not been changed. -- Marshall (who is at a WG21 meeting all week)

1 0

Boost Dinner at ISO meeting in San Diego
by Jon Kalb 07 Nov '18

07 Nov '18

If you are in, or close to, the San Diego area, please join us tomorrow (Wednesday) evening at 18:00 at Gordon Biersch (5010 Mission Center Rd, San Diego, CA 92108) for a Boost Interest Dinner. https://gordonbiersch.com/locations/san-diego/ We’ll be in the patio area. Thanks. Jon

1 0

[Boost.Asio] Allow/DisAllow client connection to Serveur.
by Gadamatik 06 Nov '18

06 Nov '18

Hello to all, I'm trying to develop a serveur that will allow/disallow a client to access internet according a ticket provided to him, just a kind of Raduis. Because Boost.Asio deal with OS, so I just want the client get access to internet if, only if he has a ticket that my server will provide him. I'm looking the way to do this but i'm really stick at this point. I'll really appreciate your strong help to find a way, just a way. I'm working on Windows. Thanks in advance. ----- La patience guide mes raisons -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

1 0

Regarding certificate verification using Asio
by David Demelier 05 Nov '18

05 Nov '18

Hello, This is more a general question about certificates verification in SSL contexts. I hope this is not too much offtopic. I know how asymmetric encryption works, but I never dig a lot into the process of certificates verification. I know how certificate checks are made with browsers, the server must have a certificate signed by a trusted CA. But then, I must admit that I don't know many more. For example, A lot of Linux package managers use package signing to be sure that packages downloaded are correctly built from the vendor. But this is another topic I guess. Now, for example, I would like to create my own server process and my own client. They are not open to the internet, so no need to buy trusted authority certificates. So by generating self-signed certificate and private key file. The server can run. The question is: how the client be sure that it is connecting to the right server? Do this client needs to have the same certificate on its local machine and use it? If yes, should I use ssl::context::load_verify_file and ssl::verify_peer and I'm done? If you have some resources to advice me on the certificate check mechanisms, please give me. Regards -- David

2 1

Compile Boost 1.64 on ARM64
by Lior Koskas 04 Nov '18

04 Nov '18

Hello, I'm trying to compile boost on my 64 ARM machine. In order to compile I ran this command ./bootstrap.sh && ./b2. When I'm looking at the output of the b2 program, I noticed that it does not recognize my machine as ARM architecture: Performing configuration checks - 32-bit : no (cached) - 64-bit : yes (cached) - arm : no (cached) - mips1 : no (cached) - power : no (cached) - sparc : no (cached) - x86 : yes (cached) How can I enforce boost to compile as ARM64 architecture? Thank you, -- Lior

1 0

Missing boost/test/utils/trivial_singleton.hpp header
by Martin Beseda 04 Nov '18

04 Nov '18

Hello everybody, I'm beginning with the Boost.Test library and I wanted to use it together with Turtle Mock library <http://turtle.sourceforge.net/>, as it claims to be developed specifically for usage with Boost. The problem is, I'm getting the error, that boost/test/utils/trivial_singleton.hpp is missing. I'm using other Boost headers with no problem, so I had a look at the codes and it seems, that trivial_singleton.hpp header is not there. Also, I couldn't find him in the online repository. Was the header relocated or removed? Thank you very much for the information, Martin

2 1

[release] 1.69.0 closed for major changes
by Marshall Clow 01 Nov '18

01 Nov '18

The master branch is now closed for new libraries and breaking changes, and will be closing for the beta in one week. Also, if you're ready, you can also add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_69_0.q… > After editing the release notes, you should get a form to create a pull request, remember to submit it, otherwise I won't see your change. Thanks, -- The Boost Release Team

1 0

Web based C++ compiler with Boost support
by Michael Powell 01 Nov '18

01 Nov '18

Hello, Does anyone happen to know of a decent web based C++ compiler with Boost support? Specifics, if possibly, include support for MSVC, especially VS2017 C++, Spirit, probably C++17 as well, etc. I know that's probably asking for a lot, but my searches aren't turning up very much, or it is getting confused with literally "building Boost", which is a bit OT. :-) Thanks! Best regards, Michael Powell

5 10

Roughed in Proto2 Spirit parser
by Michael Powell 31 Oct '18

31 Oct '18

Hello, I'm working on a Proto2 Spirit parser. Right now it's really roughed in. There is no AST at the moment. That's TBD; right now I am focused on just getting the build to work. https://gcc.godbolt.org/z/_nBsKi The code is there, but the compiler driving the web site is choking on Spirit. I put the rules in up front; probably ambitious on my part, and am finding an error on: _range %= _int_lit >> -(lit("to") >> (_int_lit | lit("max")); Severity Code Description Project File Line Suppression State Error C1075 '{': no matching token found Kingdom.OrTools.Sat.Params.Generator g:\source\kingdom software\kingdom.ortools\standard\src\kingdom.ortools.sat.params.generator\proto_parser.cpp 205 The Proto2 grammar states: range = intLit [ "to" ( intLit | "max" ) ] I'm considering pairing it back significantly and building the grammar up gradually to make sure it all builds. That's probably a sounder approach anyway. Eventually I want to build up the AST in such a way as to facilitate generating some boilerplate adapter code in my target language (C#). Thoughts? Best regards, Michael Powell https://developers.google.com/protocol-buffers/docs/reference/proto2-spec

2 2

Error building Spirit parser in VS2017
by Michael Powell 31 Oct '18

31 Oct '18

Hello, I am receiving the following error building against the latest VS2017 ... 1>Version_Parser.cpp 1>d:\dev\boost.org\boost_1_68_0\boost\iostreams\positioning.hpp(96): error C4996: 'std::fpos<_Mbstatet>::seekpos': warning STL4019: The member std::fpos::seekpos() is non-Standard, and is preserved only for compatibility with workarounds for old versions of Visual C++. It will be removed in a future release, and in this release always returns 0. Please use standards-conforming mechanisms to manipulate fpos, such as conversions to and from streamoff, or an integral type, instead. If you are receiving this message while compiling Boost.IOStreams, a fix has been submitted upstream to make Boost use standards-conforming mechanisms, as it does for other compilers. You can define _SILENCE_FPOS_SEEKPOS_DEPRECATION_WARNING to acknowledge that you have received this warning, or define _REMOVE_FPOS_SEEKPOS to remove std::fpos::seekpos entirely. 1>c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.15.26726\include\iosfwd(59): note: see declaration of 'std::fpos<_Mbstatet>::seekpos' With my grammar: BOOST_FUSION_ADAPT_STRUCT(NS_VERSION_H::version, _major, _minor, _patch, _build); template <typename It> struct version_parser : qi::grammar<It, NS_VERSION_H::version()> { version_parser() : dot_('.'), version_parser::base_type(_start) { using qi::lit; using qi::hold; using qi::short_; _major_part = short_; _minor_part = lit(dot_) >> short_; _patch_part = lit(dot_) >> short_; _build_part = lit(dot_) >> short_; _start = hold[_major_part >> _minor_part >> -(_patch_part >> -_build_part)]; } private: qi::rule<It, NS_VERSION_H::version()> _start; const char dot_; qi::rule<It, short()> _major_part; qi::rule<It, short()> _minor_part; qi::rule<It, short()> _patch_part; qi::rule<It, short()> _build_part; }; bool try_parse_version(const std::string& s, NS_VERSION_H::version& v) { using It = std::string::const_iterator; using qi::parse; It first = s.begin(), last = s.end(); if (!parse(first, last, version_parser<It>{}, v)) { std::cout << "Failed to parse: '" << s << "'" << std::endl; return false; } const auto dot_ = "."; std::cout << "version: " << v._major << dot_ << v._minor << dot_ << v._patch << dot_ << v._build << std::endl; return true; } At present I have not furnished any Spirit flags or anything of that sort; pretty much taking the includes, grammar, building as-is. Secondary to the error, I want the parser to reject spaces, should just be numeric (short) and the dot delimiter. Best regards, Michael Powell

2 8

Boost "Application" concept?
by Michael Powell 30 Oct '18

30 Oct '18

Hello, I know Boost has within its repo the elements of bits that comprise a typical application; i.e. program options, for starters, etc. However, I was curious, is there a library in the Boost repo that wraps it all up in a prescribed format? Or a handle of recipes? Things I would expect to find include the program options, ability to run, with some arguments, etc. Not an exhaustive set of expectations, to be sure. Thanks for the feedback! Cheers, Michael W Powell

2 1

Boost 1.68.0 - boost hashing changed ?
by Shailja Prasad 28 Oct '18

28 Oct '18

Hello there, I was trying to upgrade boost 1.53.0 to boost 1.68.0. But, it looks like hashing code generation has changed, since the following line gives two different hashcode for same string input. boost::hash<string> namehash; size_t hashCode = namehash( name); Where name is string, an e.g “abcdefg” With boost 1.53.0 the hashCode is 168904 And with boost 1.68.0 the hashCode is 69530. I am giving just sample random number here, those two numbers are never equal, with everything remain the same, only change boost version on EL6 Linux machine with GCC 4.9 compiler. This is blocking me to upgrade to newer version of boost. I appreciate if anyone has some info on this. Thanks

6 10

Mailman upgrade
by Brad Johnson 27 Oct '18

27 Oct '18

Happy Late October all. Just a quick notification that mailman upgraded from 2.1.26 -> 2.1.29 at 27-Oct-2018 02:50 UTC. Release notes for 2.1.27, 2.1.28, and 2.1.29: https://launchpad.net/mailman/2.1/2.1.27 https://launchpad.net/mailman/2.1/2.1.28 https://launchpad.net/mailman/2.1/2.1.29 Sanity checks on test mailing list shows mail is still flowing and archiving. Any questions or concerns, please let me know at this address or sysadmin(a)boost.org. Thanks, -- Brad Johnson Ciere Consulting 916.877.6030 brad.johnson(a)ciere.com ciere.com

1 0

Boost Multiprecision list.
by A Z 26 Oct '18

26 Oct '18

I am aware the the boost multiprecision library is a headers library. -Is Boost multiprecision accurately arbitrary precision, ie. can have its number precisions and scales always made to a larger number, contingent only to the amount of available OS memory? -If I want to use boost Boost multiprecision on its own, what is the name of the Boost .dll or .lib files that have all the headers in it? I need a minimal set of files in order to run multiprecision on its own. ?

3 2

Boost iterator facade implementation
by rmawatson rmawatson 26 Oct '18

26 Oct '18

https://github.com/boostorg/iterator/blob/boost-1.63.0/include/boost/iterat… I was wondering about is_non_proxy_reference<Reference,Value> in this metafunction. It appears to select between postfix_increment_proxy<Iterator> and writable_postfix_increment_proxy<Iterator> based on whether Reference is the same type as Value ignoring cv& what is the case that writable_postfix_increment_proxy<Iterator> is selected. So when is Reference going to be a different 'base type' to Value? is this to support user returning their own proxy or something?

1 0

[asio] Advice on implementing rate-limiting for async_write
by Kyle Ketterer 25 Oct '18

25 Oct '18

Hello fellow Boost friends, I am looking into some advice on implementing rate-limiting using using Boost ASIO with async_write. I am working on a Enterprise File Backup solution named Vessel @ https://github.com/VesselEnterprise/vessel-backup. My project uses Boost through and through. The use case is as follows: - Many users on the same network/subnet may be transferring files at once - I want to add the feature of being able to limit upload speed to the storage provider (AWS, Azure, etc) The request starts as follows: (pseudo code) Let's say we have a string of 1000 bytes we want to send to a server: const std::string& request //Passed to member function and make_shared<>() > to member var on stack to ensure lifetime of async operation Let's also say we want to limit the transfer speed to 100 bytes/second size_t transfer_max = 100; Should we start the request with async_write() on the socket? //Ensure that no more than transfer_max bytes are sent during the first write > boost::asio::async_write(*m_socket, boost::asio::buffer(http_request, > transfer_max), boost::bind(&HttpClient::handle_write, this, > boost::asio::placeholders::error, > boost::asio::placeholders::bytes_transferred )) ; > Here is where I have questions. In the completion handler handle_write(...), we need to continue to call async_write() until all bytes have been written and determine the current transfer rate, and sleep the thread if necessary. When sending the next set of bytes, is it best to explicitly declare a buffer and consume or use a pointer to the char array? void HttpClient::handle_write( const boost::system::error_code& e, size_t > bytes_transferred ) > { > /** > ** Do some stuff here to determine transfer rate, and sleep if > necessary... > */ > > //Pseudocode > if ( transfer_rate > transfer_max ) > { > //Possibility 1? > auto buffer = boost::asio::buffer(request, transfer_max); > buffer.consume(total_bytes_transferred_so_far); > boost::asio::async_write(*m_socket, buffer, > boost::bind(&HttpClient::handle_write, this, > boost::asio::placeholders::error, > boost::asio::placeholders::bytes_transferred )) ; > //Possibility 2? > boost::asio::async_write(*m_socket, > boost::asio::buffer(&request[total_bytes_transferred_so_far], > transfer_max), boost::bind(&HttpClient::handle_write, this, > boost::asio::placeholders::error, > boost::asio::placeholders::bytes_transferred )) ; > return; > > } > //...eof > } Advice on the topic is greatly appreciated. If I am way off, just let me know :) Thanks! -- Kyle Ketterer <reminisc3(a)gmail.com>

2 1

[gil] Who uses Boost.GIL?
by Mateusz Loskot 24 Oct '18

24 Oct '18

Dear Boost Users, I'm interested in collecting a list of software projects using or depending on, directly or indirectly, Boost.GIL. If you stick boost::gil anywhere in your code, please tell me about it, drop link to your project. I'd like to list users of GIL at https://github.com/boostorg/gil/wiki/Who-Uses-GIL If you ask me to not to, I'll respect your request. Thank you! Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

3 4

[release] 1.69.0 deadline for new libraries approaching
by Marshall Clow 22 Oct '18

22 Oct '18

It's that time again! On Wednesday, the master branch will be closed for adding new libraries. Upcoming dates: * 24-Oct: Boost 1.69.0 closed for new libraries and breaking changes * 31-Oct: Boost 1.69.0 closed for major code changes * 7-Nov: Boost 1.69.0 closed for beta * 14-Nov: Boost 1.69.0 beta 1 * 5-Dec: Boost 1.69.0 closed for release * 12-Dec: Boost 1.69.0 release -- The Boost Release Team

1 0

[Range] Help with syntax
by Robert Jones 19 Oct '18

19 Oct '18

Given struct S { int i( ) const; }; vector<S> v; set<int> s; I want to write (approximately) for_each( v | transform( []( const S & s ){ return s.i( ); } ), s.emplace ); With the intention putting all the i's extracted from v into the set s. My syntax is all over the place, and I'm not sure how to express the s.emplace bit. Also is there a better way to say the whole thing? If I were doing push_back instead of emplace there's a facility especially for that, but I guess Boost::Range hasn't embraced emplace because range-v3 is around now. I'm sure some of you are fluent in this stuff! Kind Regards Rob.

3 2

[Boost-serialization] undefined reference error
by phillip mobley 19 Oct '18

19 Oct '18

Hello all, I ma having a major issue with the boost library. I have been having this issue for a few days now and I can't seem to figure out what the problem is. Basically, I get this error message after my linker: "undefined reference to `boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::save(std::string const&)'" My complete linker command is as follows: " -L. -L/usr/lib/x86_64-linux-gnu -L/usr/local/lib -L/usr/lib/lapack -lfreetype -lGLEW -llapack -lboost_serialization -lglut -lGL -lGLU -L/usr/local/lib -pthread -lwx_gtk2u_xrc-3.1 -lwx_gtk2u_stc-3.1 -lwx_gtk2u_richtext-3.1 -lwx_gtk2u_ribbon-3.1 -lwx_gtk2u_propgrid-3.1 -lwx_gtk2u_aui-3.1 -lwx_gtk2u_gl-3.1 -lwx_gtk2u_html-3.1 -lwx_gtk2u_qa-3.1 -lwx_gtk2u_adv-3.1 -lwx_gtk2u_core-3.1 -lwx_baseu_xml-3.1 -lwx_baseu_net-3.1 -lwx_baseu-3.1" I built Boost 1.64 from the source and kept the default values. I also built the whole library. My Boost library is built into the /usr/local folder. I am pretty sure that I am referencing the linker libraries correctly but I can't seem to figure out why I would be getting this error message. Has anyone had an issue similar to this before?

1 0