February 2014 - Boost - lists.preview.boost.org

[testing] Strange Darwin test failures
by John Maddock 08 Feb '14

08 Feb '14

Does anyone know why this would happen: http://www.boost.org/development/tests/develop/developer/output/marshall-ma… program exits with: libc++abi.dylib: terminate called throwing an exception Googling around finds: http://apple.stackexchange.com/questions/103649/macports-dylib-failure-with… which suggests some sort of toolset misconfiguration? Thanks, John.

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Phoenix 3.0.4 on master. Fixes include silent bugs.
by Fletcher, John P 07 Feb '14

07 Feb '14

Phoenix 3.0.4 is now on master and will I hope be included in the next release of Boost. There are many fixes to bugs which are documented in libs/phoenix/ChangeLog In particular there are fixes for #5715 and #5824. These are important as they were silent bugs which meant that code did not work correctly. This means that it is possible that there is code using phoenix where the results could change when adopting this release. There are many fixes still to be done which are documented in the TODO section of the changelog. Please report any concerns or bugs either through trac or by responding to this message. John Fletcher

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[modular-boost] /boost//headers error
by Thomas Suckow 07 Feb '14

07 Feb '14

I am seeing a strange discrepancy between building the headers target from the command line vs including it as a dependency in another target. In our own projects we 'use-project /boost : $(PATH_TO_BOOST) ;' and use the headers target. But as a reproducible example, if I add /boost//headers to tools/quickbook/src/Jamfile.v2 I get: http://pastebin.com/KMcMSLZW I tried to debug it, but alas my skills at boost-build seem to be insufficient. It is interesting to note however that when looking at 'b2 -d5' output 'sequence.join library-name-headers .' seems to be invoked when it fails, yet that does not occur when it succeeds. If anyone has any ideas on how to get this working again, I would be happy to look into this more. -- Thomas I for one welcome our new git overlords.

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GSoC Hypergeometric functions (Pratyaksh Sharma)
by Pratyaksh Sharma 07 Feb '14

07 Feb '14

Hello I'm interested in the Boost.Math Generalized Hyper geometric Functions project. Can anyone give some pointers on where to begin? I have sufficient experience with hypergeometric functions, but don't know exactly how to contribute to Boost. Just to start the discussion: Does everyone agree that a variety of methods need to employed for calculating the functions for different ranges of parameters? I'm familiar with methods that utilize the Gauss-Jacobi quadrature to solve the differential equation of concern, and also the Taylor series methods for smaller values of |a| and |z|. Any other ideas? Cheers, Pratyaksh

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Regression tests for 'develop'
by Edward Diener 06 Feb '14

06 Feb '14

Are the regression tests for 'develop' for any particular library running the 'develop' branch of that library against the 'master' branch of all other libraries ? Or is the regression test for 'develop' for any particular library running against the 'develop' branch of all other libraries ?

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sqlpp11: SQL for C++
by Roland Bock 06 Feb '14

06 Feb '14

Hi, over the last four or five years I developed several SQL libraries for C++. With C++11 I was finally able to create an SQL library that meets my own expectations and requirements. It is being used in production, I recently put it on github, and I would really like to hear from you guys whether this is something that could be interesting for you personally or for boost? https://github.com/rbock/sqlpp11 https://github.com/rbock/sqlpp11/wiki sqlpp11 is a template library representing an embedded domain specific language (EDSL) that allows you to * define types representing tables and columns, * construct type safe queries checked at compile time for syntax errors, type errors, name errors and even some semantic errors, * interpret results by iterating over query-specific structs with appropriately named and typed members. This results in several benefits, e.g. * the library user operates comfortably on structs and functions, * the compiler reports many kinds of errors long before the code enters unit testing or production, * the library hides the gory details of string construction for queries and interpreting string based results returned by select calls. I.e. you don't need to use strings in query construction where you wouldn't use them in SQL and there is no need to use positional arguments or to parse strings when obtaining fields from a result row (the latter being true unless you do not know which columns to select at compile time). The library supports both static and dynamic queries. The former offers greater benefit in terms of type and consistency checking. The latter makes it easier to construct queries on the flight. Specific traits of databases (e.g. unsupported or non-standard features) are known at compile time as well. This way, the compiler can tell the developer at compile time if a query is not accepted by the database (e.g. if a feature is missing). And the library can form the query in the correct manner, for instance if the engine uses concat instead of operator|| to concatenate strings. Two Examples: ============= Static Select: -------------- // selecting zero or more results, iterating over the results for (const auto& row : db.run( select(foo.name, foo.hasFun) .from(foo) .where(foo.id > 17 and foo.name.like("%bar%")))) { if (row.name.is_null()) std::cerr << "name will convert to empty string" << std::endl; std::string name = row.name; // text fields are implicitly convertible to string bool hasFun = hasFun; // bool fields are implicitly convertible to bool } Dynamic Select: ---------------- auto s = dynamic_select(db, tab.foo).dynamic_columns().from(tab); if (userWantsBar) s.add_column(tab.bar); for(const auto& row : run(s)) { std::cerr << "row.foo: " << row.foo; if (userWantsBar) std::cerr << "row.bar" << row.at("bar"); std::cerr << std::endl; }; Please let me know your questions/thoughts/suggestions/rants. Contributions welcome, of course :-) Regards, Roland

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[config] BOOST_NO_CXX11_ALLOCATOR and template aliases
by Peter Dimov 06 Feb '14

06 Feb '14

VC11 appears to not define BOOST_NO_CXX11_ALLOCATOR. However, as std::allocator_traits contains two template aliases, rebind_alloc and rebind_traits, and VC11 doesn't support template aliases, it has nonstandard definitions of these two. This is obviously a problem for code that wants to use std::allocator_traits. One way to fix that is for the user code to check BOOST_NO_CXX11_TEMPLATE_ALIASES and if so, refrain from using std::allocator_traits. Another is to just not define BOOST_NO_CXX11_ALLOCATOR for VC11. (VC12 is conforming.) I tend to be in favor of the second option, as the effect would essentially be the same.

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What is trac doing and how do I stop it doing it??
by Fletcher, John P 06 Feb '14

06 Feb '14

I am attempting to update a ticket and I am getting this: ------------------ Captcha Error Submission rejected as potential spam (Content contained 1 blacklisted patterns) Trac thinks your submission might be Spam. To prove otherwise please provide a response to the following. ------------------- I would not mind but there is nothing to respond to and what I have typed seems to be lost. Where is there guidance on how to avoid this problem, please? John

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Re: [boost] SQL: next iteration of sqlpp11
by Sebastian Theophil 06 Feb '14

06 Feb '14

> On 2014-02-03 16:03, Roland Bock wrote: > In most usecases I encountered so far, it is totally OK to interpret NULL > values like default values, e.g. NULL strings and empty strings, or NULL > foreign keys or 0LL. For those usecases it would be quite annoying to have to > check if there really is a value, or always use get_optional_value_or... Hi Roland, while I can very well imagine that these "use-cases" exist, I would not like the library to make this the default. I think using boost::optional is the canonical solution that is also impossible to misinterpret. Treating non-existent values the same as default-initialized values seems error-prone if not wrong in general. The library should not prevent me from treating string "" differently from NULL, which currently it does. On the other hand, if the library did return optionals, implementing the behaviour you describe on top of it is trivial: boost::optional<T> t; t.get_value_or( T() ); If it helps my argument, both Scala Anorm and Scala Slick represent nullable columns as optional types: http://www.playframework.com/documentation/2.0/ScalaAnorm http://slick.typesafe.com/doc/2.0.0/schemas.html Regards Sebastian PS: I hope to look at your library in more detail in the coming weeks and I am really looking forward to that. Great work so far. -- Dr. Sebastian Theophil | stheophil(a)think-cell.com Senior Software Engineer think-cell Sales GmbH & Co. KG | Chausseestr. 8/E | 10115 Berlin | Germany http://www.think-cell.com | phone +49 30 666473-10 | US phone +1 800 891 8091 Amtsgericht Berlin-Charlottenburg, HRA 44531 | European Union VAT Id DE815233792 General partner: think-cell Operations GmbH | Amtsgericht Berlin-Charlottenburg HRB 129917 Directors: Dr. Markus Hannebauer, Dr. Arno Sch?dl

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Large Bitset to download?
by Aleksey Yakovlev 05 Feb '14

05 Feb '14

Dear List, This is my first post to the list. I’ve subscribed to get some info about Zachary Turner project “Large Bitset” (based on Joachim Faulhaber ICL). What’s the status of this project? It looks promising for us, so I’d like to download sources and take a dig into them – to test, to estimate limits, performance etc. Please help, Thanks, Aleksey This message contains confidential information. If you are not the intended recipient you are hereby notified that disclosing,copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Please notify the sender immediately and delete this e-mail from your system.

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