- Boost-users - lists.boost.org

Filesystem library and virtual
by Olivier Tristan 28 Jul '15

28 Jul '15

Hi Guys, I'm wondering if the possibility to handle custom filesystem is planned at some point in the Filesystem library ? My goal is to manage a virtual filesystem contained in a "big file" or in an archive in a transparent way with the other files on the system. Thanks, -- Olivier Tristan Research & Development www.uvi.net

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Betweenness Centrality Test
by Mayank Bakshi 28 Jul '15

28 Jul '15

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unsupported version problem of serialization of graph
by breadbread1984 28 Jul '15

28 Jul '15

I am using boost graph library. I can serialize the graph successfully. But when deserialized a graph from the file, an unsupported version exception was throwed out. The Graph structure is pasted [here] (http://codepad.org/m7F21t4j) what shall I do to solve the problem. Thx!

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Boost.Log
by Leon Mlakar 27 Jul '15

27 Jul '15

Hi, I've started looking into Boost.Log as one of the possible solutions for out multi-platform project with, alas, Microsoft Windows being one of the them platforms. While the solution is multi-threaded, we are trying to avoid any thread synchronization on common resources by using sequential task queues associated with these resources. The resulting internal architecture is thus fully asynchronous with no synchronization points between worker threads. So I'm trying to fit Boost.Log into this, and the documentations, while exhaustive, still leaves some questions unanswered. Or perhaps I missed them. For instance, as far as the sources go, the library offers two logger flavors ... thread safe (I'm assuming guarded by mutex) and single threaded variants. I'm inclined towards using the latter (obviously, don't want to sync on mutex) but that would mean creating thousands of logger instances and I don't have a feeling how heavy or lightweight the logger is. Hence the first questions: 1. How heavy the logger is and what would it mean to have thousands of them around? 2. Why is there a need for _mt variants? Solely to protect logger internal data or to synchronize operations towards the core? 3. Is there anything else the loggers do apart from storing source specific attributes and associating them with the record, and serving as an open/push frontend to the core? And since the alternative is to directly use the core rather than going through the loggers, this immediately raises the next question: 4. are the following core operations internally synchronized: core::get(), core::open_record(), core::push_record()? And the final question: 5. If we were to go with using the core directly, would it be better to store shared pointer obtained via core::get() or to call core::get() for each log (basically, whether is it okay to store shared pointers to core up until the start of the end of the destruction sequence of the process? I think the sinks are more thoroughly covered in the docs. I'm unsure at the moment whether to use one of those already available in the library with the asynchronous frontend, or go for the unlocked frontend with the own backend associated with the task queue. While I'm aware I did not provide enough information to directly ask the question, any thoughts on this would nevertheless be welcome. Thank you and best regards, Leon

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Boost release 1.59.0 beta 1 is now available from SourceForge
by Marshall Clow 25 Jul '15

25 Jul '15

Boost release 1.59.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/boost/1.59.0.beta.1/ For details of what's in the release, see http://www.boost.org/users/history/version_1_59_0.html. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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[filesystem] problem: is_regular_file and deduplified files (reparse+sparse)
by Paul Harris 24 Jul '15

24 Jul '15

Hi guys, I'm seeing a lot of failures all of a sudden, its a serious problem. I imagine some of you may start seeing the same failures too very soon. I'm seeing it with boost 1.58.0. There is a related bug already entered here: https://svn.boost.org/trac/boost/ticket/11057 I can't seem to log on and update this ticket. But the problem extends further than that ticket. Windows Server 2003 support has been dropped by Microsoft, and a lot of IT depts around the world are switching over to the latest Windows Server. With this server comes the new "dedup" feature, that can automatically deduplify files. This happens on a schedule, eg 2am saturday. So suddenly we are getting messages of failures of software from all over the place, due to fs::is_regular_file() Deduped files have the REPARSE and SPARSE flag set. On the command line, you can run FSUTIL REPARSEPOINT QUERY and the "Reparse Tag Value" is 0x80000013 Which is a relatively new flag known as IO_REPARSE_TAG_DEDUP https://msdn.microsoft.com/en-us/library/windows/desktop/aa365740%28v=vs.85… These files act as normal files, you can fopen and fread them, so I assume they should be treated almost like symlink by boost... perhaps not quite a symlink because I assume the "lstat" link properties are identical to the file's stat properties. Typically, I iterate over directories and only process files if fs::is_regular_file(filename) is true. I wrote some code to check what the properties were on these files, and its not any of the possible enums detected by file_status::type(). ideas? Best regards, Paul

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Re: [Boost-users] problem of getting vertex_index_t property
by breadbread1984 24 Jul '15

24 Jul '15

Thx for your reply. But I use vecS to store vertices instead of setS. The setS is for storing edges. There should be something else going wrong. 在 2015年7月23日星期四 10:32:28，boost-users-request@lists.boost.org 写道： > Send Boost-users mailing list submissions to > boost-users(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://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: [interval] Errors using transc.hpp WAS: Power (Sensei) > 2. problem of getting vertex_index_t property with BGL > (breadbread1984) > 3. Re: problem of getting vertex_index_t property with BGL > (Jeremiah Willcock) > 4. Re: Boost.DateTime and leap year/leap seconds (Auer, Jens) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 23 Jul 2015 10:03:47 +0200 > From: Sensei <senseiwa(a)gmail.com> > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] [interval] Errors using transc.hpp WAS: > Power > Message-ID: <55B09FE3.20108(a)gmail.com> > Content-Type: text/plain; charset=utf-8; format=flowed > > Dear all, > > I've tried to move beyond simple exp/log functions, but this problem > > > /usr/local/include/boost/numeric/interval/transc.hpp:47:42: No member > > named 'log_down' in 'boost::numeric::interval_lib::rounded_math<double>' > > > > /usr/local/include/boost/numeric/interval/transc.hpp:34:16: No member > > named 'exp_down' in 'boost::numeric::interval_lib::rounded_math<double>' > > arises with *all* of the functions contained in transc.hpp, and I don't > know what I'm doing wrong here. > > Can anyone help me? > > > Thanks! > > > ------------------------------ > > Message: 2 > Date: Thu, 23 Jul 2015 18:25:39 +0800 > From: breadbread1984 <breadbread1984(a)163.com> > To: boost-users(a)lists.boost.org > Subject: [Boost-users] problem of getting vertex_index_t property with > BGL > Message-ID: <2807116.uu1eRmarTQ@xieyi-paf4> > Content-Type: text/plain; charset="utf-8" > > I am using boost graph library. I found there is a built in property > vertex_index_t corresponding to every vertex from the document > [here](http://www.boost.org/doc/libs/1_58_0/libs/graph/doc/adjacency_list.h > tml). But when I get the vertex_index_t property the compiler prompt the > following error: > > CooperativeGraph.h:59:36: required from here > /usr/include/boost/graph/detail/adjacency_list.hpp:2498:29: error: forming > reference to void typedef value_type& reference; > ^ > /usr/include/boost/graph/detail/adjacency_list.hpp:2499:35: error: forming > reference to void typedef const value_type& const_reference; > ^ > /usr/include/boost/graph/detail/adjacency_list.hpp:2502:47: error: forming > reference to void <Graph, value_type, reference, Tag> type; > ^ > /usr/include/boost/graph/detail/adjacency_list.hpp:2504:53: error: forming > reference to void <Graph, value_type, const_reference, Tag> const_type; > ^ > CooperativeGraph.cpp: In member function ?void > CooperativeGraph::getProperties()?: CooperativeGraph.cpp:384:35: error: no > matching function for call to ?get(boost::vertex_index_t, Graph&)? > vertex_index = get(vertex_index,g); > ^ > I defined the data structure as follows > > typedef property<vertex_BatteryLevel_t,int, > property<vertex_ObservationHistory_t,deque<Observation>, > property<vertex_name_t,uuid> > > > vertex_state; > > typedef property<edge_QFunction_t,QTable, > property<edge_Eligibility_t,Eligibility> > > > edge_qfunction; > > typedef adjacency_list< > vecS,setS,directedS, > vertex_state, > edge_qfunction > > > Graph; > > Does anyone know what I am doing wrong? Why can't I get the vertex_index_t > property. Thanks! > > > > ------------------------------ > > Message: 3 > Date: Thu, 23 Jul 2015 14:06:03 +0000 (UTC) > From: Jeremiah Willcock <jewillco(a)yahoo.com> > To: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> > Subject: Re: [Boost-users] problem of getting vertex_index_t property > with BGL > Message-ID: > <983493185.1183146.1437660363876.JavaMail.yahoo(a)mail.yahoo.com> > Content-Type: text/plain; charset=UTF-8 > > >________________________________ > > > > From: breadbread1984 <breadbread1984(a)163.com> > > > >To: boost-users(a)lists.boost.org > >Sent: Thursday, July 23, 2015 4:25 AM > >Subject: [Boost-users] problem of getting vertex_index_t property with BGL > > > > > >I am using boost graph library. I found there is a built in property > >vertex_index_t corresponding to every vertex from the document > >[here](http://www.boost.org/doc/libs/1_58_0/libs/graph/doc/adjacency_list. > >html). But when I get the vertex_index_t property the compiler prompt the > >following error: > > > >CooperativeGraph.h:59:36: required from here > >/usr/include/boost/graph/detail/adjacency_list.hpp:2498:29: error: forming > >reference to void> > > typedef value_type& reference; > > > > ^ > > > >/usr/include/boost/graph/detail/adjacency_list.hpp:2499:35: error: forming > >reference to void> > > typedef const value_type& const_reference; > > > > ^ > > > >/usr/include/boost/graph/detail/adjacency_list.hpp:2502:47: error: forming > >reference to void> > > <Graph, value_type, reference, Tag> type; > > > > ^ > > > >/usr/include/boost/graph/detail/adjacency_list.hpp:2504:53: error: forming > >reference to void> > > <Graph, value_type, const_reference, Tag> const_type; > > > > ^ > > > >CooperativeGraph.cpp: In member function ?void > >CooperativeGraph::getProperties()?: CooperativeGraph.cpp:384:35: error: no > >matching function for call to ?get(boost::vertex_index_t, Graph&)?> > > vertex_index = get(vertex_index,g); > > > > ^ > > > >I defined the data structure as follows > > > >typedef property<vertex_BatteryLevel_t,int, > > > > property<vertex_ObservationHistory_t,deque<Observation>, > > > > property<vertex_name_t,uuid> > >> > >> vertex_state; > > > >typedef property<edge_QFunction_t,QTable, > > > > property<edge_Eligibility_t,Eligibility> > >> > >> edge_qfunction; > > > >typedef adjacency_list< > > > > vecS,setS,directedS, > > vertex_state, > > edge_qfunction > >> > >> Graph; > > > >Does anyone know what I am doing wrong? Why can't I get the vertex_index_t > >property. Thanks! > Your graph type has setS as its vertex container. Try using vecS instead to > get the vertex_index property to be present. > > -- Jeremiah Willcock > > > ------------------------------ > > Message: 4 > Date: Thu, 23 Jul 2015 14:31:51 +0000 > From: "Auer, Jens" <jens.auer(a)cgi.com> > To: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> > Subject: Re: [Boost-users] Boost.DateTime and leap year/leap seconds > Message-ID: > <E47848702ADBE04EA7ECF45E05F60B6DF98E840C(a)SE-EX020.groupinfra.com> > Content-Type: text/plain; charset="utf-8" > > Hi Howard, > > Thank you very much. That basically made my day! > > We have no restrictions on the compiler, currently I'm using gcc 4.9 in > C++-14 mode. I think I can also justify using a time handling library, so > the chances are very good that we will use your library. > > Many thanks and best wishes, > Jens > > -- > Dr. Jens Auer | CGI | Software Engineer > CGI Deutschland Ltd. & Co. KG > Rheinstra?e 95 | 64295 Darmstadt | Germany > T: +49 6151 36860 154 > jens.auer(a)cgi.com > Unsere Pflichtangaben gem?? ? 35a GmbHG / ?? 161, 125a HGB finden Sie unter > de.cgi.com/pflichtangaben. > > CONFIDENTIALITY NOTICE: Proprietary/Confidential information belonging to > CGI Group Inc. and its affiliates may be contained in this message. If you > are not a recipient indicated or intended in this message (or responsible > for delivery of this message to such person), or you think for any reason > that this message may have been addressed to you in error, you may not use > or copy or deliver this message to anyone else. In such case, you should > destroy this message and are asked to notify the sender by reply e-mail. > > -----Original Message----- > From: Boost-users [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Howard Hinnant Sent: 22 July 2015 21:29 > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] Boost.DateTime and leap year/leap seconds > > I?ve been following this thread with interest. > > On Jul 22, 2015, at 8:59 AM, Auer, Jens <jens.auer(a)cgi.com> wrote: > > Reading the documentation I think that will not be correct when there were > > leap seconds. > Correct. As Jeff said earlier, leap second support is not in the current > library, but might be a feature in a future boost date-time 2.0. > > If you are using a C++11 or C++14 compiler, there is a library that will > handle this problem with leap seconds taken into account for you: > > http://howardhinnant.github.io/tz.html > > I doubt you can use this library as the space industry equates up-to-date > compilers with increased risk. However I mention it, as it is open source > and perhaps you can crib some of its ideas onto the current boost date-time > library. > > In a nutshell, this C++11/14 library handles leap seconds along the lines of > what Jeff suggested. Though in this case it creates a std::chrono - > compatible clock which is leap second aware: > > class utc_clock > { > public: > using duration = > std::chrono::system_clock::duration; using rep = > duration::rep; > using period = duration::period; > using time_point = > std::chrono::time_point<utc_clock>; static constexpr bool is_steady = true; > > static time_point now() noexcept; > > template <class Duration> > static > std::chrono::time_point<utc_clock, > typename std::common_type<Duration, > std::chrono::seconds>::type> > sys_to_utc(std::chrono::time_point<std::chrono::system_clock, Duration> t); > > template <class Duration> > static > std::chrono::time_point<std::chrono::system_clock, > typename std::common_type<Duration, > std::chrono::seconds>::type> utc_to_sys(std::chrono::time_point<utc_clock, > Duration> t); }; > > and includes conversions to and from std::chrono::system_clock::time_point > (which like boost date-time is based on Unix time). These conversions are > simply lookups into an ordered list of leap second transitions, resulting > in the addition or subtraction of the proper number of leap seconds. > > This could be used like so: > > struct CCSDS > { > std::uint16_t days; > std::uint32_t ms; > std::uint16_t us; > }; > > CCSDS > to_CCSDS(date::year y, std::chrono::microseconds us) > { > using namespace date; > using namespace std::chrono; > auto utc = utc_clock::sys_to_utc(day_point(y/jan/1)) + us; > auto sys = utc_clock::utc_to_sys(utc); > auto dp = floor<days>(sys); > auto d = dp - day_point(1958_y/jan/1); > us = utc - utc_clock::sys_to_utc(dp); > auto ms = duration_cast<milliseconds>(us); > us -= ms; > return {static_cast<std::uint16_t>(d.count()), > static_cast<std::uint32_t>(ms.count()), > static_cast<std::uint16_t>(us.count())}; > } > > The variable utc holds the ?year + us? as a time point with microseconds > precision. This time point counts microseconds, including leap seconds, > since 1970-01-01 00:00:00 UTC. > > The next step is find when the day started that is associated with utc. To > do this one must convert utc back to ?Unix time?, and then truncate that > time point to a precision of days, resulting in the variable dp. dp is a > count of days since 1970-01-01. Since your epoch is 1958-01-01, this is > taken into account in creating ?d?, the first value needed in your return > type. > > Now the number of microseconds since the start of the day needs to be > computed. The start of the day, dp, is converted back into the leap-second > aware system, and subtracted from the microsecond time point: utc. The > variable us is reused to hold ?microseconds since midnight?. Now it is a > simple computation to split this into milliseconds since midnight, and > microseconds since the last millisecond. > > This has all been tested with: > > void > test_to_CCSDS() > { > using namespace std::chrono; > using namespace date; > for (auto d = days{179}; d <= days{181}; ++d) > { > auto start = d + 86399s + 999999us + 0us; > for (auto us = start; us <= start + 3s; us += 1s) > { > auto t = to_CCSDS(2015_y, us); > std::cout << t.days << ' ' << t.ms << ' ' << t.us << '\n'; > } > std::cout << '\n'; > } > } > > which yields: > > 20998 86399999 999 > 20999 999 999 > 20999 1999 999 > 20999 2999 999 > > 20999 86399999 999 > 20999 86400999 999 > 21000 999 999 > 21000 1999 999 > > 21000 86398999 999 > 21000 86399999 999 > 21001 999 999 > 21001 1999 999 > > Interpretation: On 2015-06-29 23:59:59.999999 we are 1us away from the next > day. 1s later we are well into 2015-06-30. > > 24hrs later, we see a different pattern as the leap second is inserted. The > last microsecond of the day is 1s later at 2015-06030 23:59:60.999999. > > 24hrs later we are back to days with only 86400s. > > Assuming you have some conversion data to test against, this will hopefully > match up with those test cases. > > Howard > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > ------------------------------ > > End of Boost-users Digest, Vol 4202, Issue 3 > ********************************************

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question about vertex_index_t property of graph
by breadbread1984 24 Jul '15

24 Jul '15

I am using boost graph library. I want to know whether the value of vertex_index_t property is assigned and updated automatically? If I serialize a graph to a file and deserialize it, will the value of vertex_index_t property remain?

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Boost.DateTime and leap year/leap seconds
by Auer, Jens 23 Jul '15

23 Jul '15

Hi, I am considering using Boost.DateTime in one of my projects, and there have been some concerns about handling leap seconds on the customers side. The documentation says that other libraries do not handle leap seconds correctly, but it does not state that Boost.DateTime does. I found only one mail from 2009 on the mailing list asking about leap seconds, but this does not give an answer. Does anybody have some information on this? The computations I intend to do are actually rather limited. I will be given a year and a number microseconds, and have to compute the day in the year that this describes from the start of the year, together with microseconds and milliseconds in the day. So what I want to implement is a function tuple<days, milliseconds, microsends> convertTime(year, microseconds). Best wishes, Jens -- Dr. Jens Auer | CGI | Software Engineer CGI Deutschland Ltd. & Co. KG Rheinstraße 95 | 64295 Darmstadt | Germany T: +49 6151 36860 154 jens.auer(a)cgi.com<mailto:jens.auer@cgi.com> Unsere Pflichtangaben gemäß § 35a GmbHG / §§ 161, 125a HGB finden Sie unter de.cgi.com/pflichtangaben<http://de.cgi.com/pflichtangaben>. CONFIDENTIALITY NOTICE: Proprietary/Confidential information belonging to CGI Group Inc. and its affiliates may be contained in this message. If you are not a recipient indicated or intended in this message (or responsible for delivery of this message to such person), or you think for any reason that this message may have been addressed to you in error, you may not use or copy or deliver this message to anyone else. In such case, you should destroy this message and are asked to notify the sender by reply e-mail.

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problem of getting vertex_index_t property with BGL
by breadbread1984 23 Jul '15

23 Jul '15

I am using boost graph library. I found there is a built in property vertex_index_t corresponding to every vertex from the document [here](http://www.boost.org/doc/libs/1_58_0/libs/graph/doc/adjacency_list.ht…. But when I get the vertex_index_t property the compiler prompt the following error: CooperativeGraph.h:59:36: required from here /usr/include/boost/graph/detail/adjacency_list.hpp:2498:29: error: forming reference to void typedef value_type& reference; ^ /usr/include/boost/graph/detail/adjacency_list.hpp:2499:35: error: forming reference to void typedef const value_type& const_reference; ^ /usr/include/boost/graph/detail/adjacency_list.hpp:2502:47: error: forming reference to void <Graph, value_type, reference, Tag> type; ^ /usr/include/boost/graph/detail/adjacency_list.hpp:2504:53: error: forming reference to void <Graph, value_type, const_reference, Tag> const_type; ^ CooperativeGraph.cpp: In member function ‘void CooperativeGraph::getProperties()’: CooperativeGraph.cpp:384:35: error: no matching function for call to ‘get(boost::vertex_index_t, Graph&)’ vertex_index = get(vertex_index,g); ^ I defined the data structure as follows typedef property<vertex_BatteryLevel_t,int, property<vertex_ObservationHistory_t,deque<Observation>, property<vertex_name_t,uuid> > > vertex_state; typedef property<edge_QFunction_t,QTable, property<edge_Eligibility_t,Eligibility> > edge_qfunction; typedef adjacency_list< vecS,setS,directedS, vertex_state, edge_qfunction > Graph; Does anyone know what I am doing wrong? Why can't I get the vertex_index_t property. Thanks!

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