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SQL: next iteration of sqlpp11
by Roland Bock 04 Feb '14

04 Feb '14

Dear boosters, after the lively discussion about sqlpp11 in November 2013 (http://lists.boost.org/Archives/boost/2013/11/208388.php) sqlpp11 has evolved quite a bit and I want to give you an update. https://github.com/rbock/sqlpp11 *) sqlpp11 now supports prepared statements. For instance auto ps = db.prepare(select(all_of(tab)) .from(tab) .where(tab.alpha != parameter(tab.alpha))); ps.params.alpha = 42; for (const auto& row: db.run(ps)) { std::cerr << "alpha: " << row.alpha << std::endl; std::cerr << "beta: " << row.beta << std::endl; std::cerr << "gamma: " << row.gamma << std::endl; } *) Binding of parameters and results for binary transport is now supported. Both, parameters of prepared statements and results can be bound to in-memory data of the database now. In the example above, using the provided mysql connector, neither parameters nor the non-text results are converted to/from string. *) Support for multi-row insert: //First, you create an insert: auto i = insert_into(tab).columns(tab.alpha, tab.beta); //Then you add values (one or more times): i.values(tab.alpha = 7, tab.beta = "seven"); // Then you run the insert db.run(i); There is no support for array binding in sqlpp11, since this is highly vendor specific afaict. But it would be fairly easy to add support for this in the vendor-specific connector library. I'd be happy to support you if you wanted to give it a try. *) New interpreter for SQL expression trees: This has changed and improved a lot. sqlpp11 has been stripped of all vendor specific code and will serialize standard SQL. The connector libraries can specialize an interpreter template to change the representation of certain aspects. For instance, mysql would represent the concatenation of strings as CONCAT(a,b) instead of a||b. But of course, the connector libraries are not required to turn the expression into a string. They can interpret it any way they like. I strongly believe that this is going to allow for writing connectors to XML, input streams, maps, etc. (think LINQ). *) I added a sample code generator (in python) that generates table representations from a DDL Todo-List: ---------- *) More thorough documentation *) More thorough and easier to comprehend tests *) Some of you mentioned that Boost.Fusion or Boost.Preprocessor might do be able to do the job of code generation very elegantly. I won't do that myself but I'd be interested to see such solutions. Since code generation is not integral part of the library it would make sense to have such solutions as support libraries. *) Look into cursors FYI, I am going to give a talk about sqlpp11 and some template patterns used inside of it on February 27 in Munich, see http://www.meetup.com/MUCplusplus/events/160688442/ Please let me know your questions/thoughts/suggestions/rants. Contributions welcome, of course :-) Regards, Roland PS: Given enough interest, I intend to officially propose the library to boost (after several more iterations, of course). This is why I hope it is OK to discuss sqlpp11 on this mailing list every now and then.

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Regarding GSoC 2014
by shubhv＠iitk.ac.in 04 Feb '14

04 Feb '14

Hey, I am a sophomore student of Computer Science Department, IIT Kanpur, India. I have been going through the boost libraries for quite some time now, and also have read through the proposed GSoC projects in 2014. I am especially interested in the Boost.Math Generalized Hyper geometric Functions. Though I have gone through the links provided under that project and am trying to become versed with Boost's Math library, I am finding it difficult to find a starting point to contributing. I would be really glad if someone could help me in the initial phase by directing me to the right starting point and guide me through. Thanks Shubhangee Verma

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Trying modular Boost
by Paul A. Bristow 04 Feb '14

04 Feb '14

FWIW here are some things I didn't understand or did wrong. (And, of course, playing Devil's Decidedly Dumb Advocate ;-) 1 How do I know if I have the right version of Git? Open GitHub icon and check Tools/About? 2 Windows hint: If you install TortoiseGIT, avoid incompatibilities by using the command line version of Git that TortoiseGIT installs. I.E. place C:\Program Files (x86)\Git\cmd in your path ahead of any other git binaries, such as cygwin. Huh? Am I Shelling, Bashing, Batting or Powershelling? How do I do that? How do I check that I have done this right? Open a Windows command window? Many Windowers will not know how to find/edit their path (and should not need to know?). A link would help. If you have dozens of items in the path, this is pretty awkward to edit? But (after a frustrating failure to get SSH access to work - in a separate post) I got to the main course using https: https://github.com/boostorg/boost.git Submodule 'io' (https://github.com/boostorg/io.git) registered for path 'libs/io' Submodule 'iostreams' (https://github.com/boostorg/iostreams.git) registered for path 'libs/iostreams' <big snip> Cloning into 'tools/quickbook'... Submodule path 'tools/quickbook': checked out '340c65150d175ffc20a9a877247928b3ed5eba1b' Success (4040769 ms @ 31-Dec-2013 17:00:21) Just over an hour (using my nominal 10 mbps living-in-the-boondocks but line-of-sight radio link) - something that should be noted in the docs (along with a strong recommendation to send to a log file)? Other you would miss/lose this very useful info? Building the Boost C++ Libraries. Performing configuration checks - symlinks supported : no - hardlinks supported : yes - 32-bit : yes . And I could test system library OK J Phew! Paul PS I had an existing (luckily current) b2.exe at c:\program files\Boost and this is implicitly in my PATH. Do we need to be more specific about how b2 is stored and accessed? Some check that b2.exe vcvars32.bat etc are all set up correctly would be good? --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 <mailto:pbristow@hetp.u-net.com> pbristow(a)hetp.u-net.com

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Process for the Community Maintenance Team
by Marshall Clow 04 Feb '14

04 Feb '14

I’ve put up a set of procedures for the Boost Community Maintenance Team (CMT) on the wiki at: https://svn.boost.org/trac/boost/wiki/CommunityMaintenance Comments welcomed. — Marshall

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Udp Socket
by •°o.O sαмι O.o°• 04 Feb '14

04 Feb '14

Asalam-o-Aliakum and Hi all, I am having a problem with boost udp socket. My program terminates after throwing exception "host unreachable". My questions: 1). why udp socket cares for host it should just send data out of its own port and its job is done? 2). And how it knows that host is not available if udp is connection less protocol? 3). And another simple question how to avoid program termination on this exception? Best Regards; Sami Ul Haq

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Building with clang for Windows/MingW
by Edward Diener 03 Feb '14

03 Feb '14

When trying to test clang under Windows which is built with MingW, Boost Build runs with the options: -c -x c++ -O0 -g -fno-inline -Wall -g -mthreads However clang does not recognize -mthreads and flags it as an error. Is there anything I can do to remove this option from the clang++.exe command line when invoking Boost Build ?

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named_condition_any not working.
by Marius Adrian DOBRESCU 02 Feb '14

02 Feb '14

Hello! I tried to use into my code an interprocess mechanism like producer/multiple consumers with named_sharable_mutexes. I found out that named_condition_any is not working with any kind of scoped locks. Neither with sharable_mutex or simple named_mutex. It takes the lock successful but cannot unblock another process when notify is called. I used linux, gcc 4.8, just basic build, linking with pthreads. Is this a known issue to you because I couldn't find any info related on the Internet? Maybe I can take a look next week what is in there... Adrian

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http://lists.boost.org/Archives/boost/2014/01/211169.php
by Gilbert Polo 02 Feb '14

02 Feb '14

Thank you for the simple explanation. Somehow I lost sight of the forest for the trees or its a lot easier to see when the obvious is pointed out.

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[C++11] Is conditional code allowed?
by Fletcher, John P 02 Feb '14

02 Feb '14

I am working on bugs in boost phoenix. I have found some problems eg. #7624 which run fine with C++11 with either Clang 3.4 or gcc 4.8.2. I also have a patch which has been suggested for bug #8704 which uses C++11. Is there a way to incorporate C++11 only code into tests or the actual headers. If so, is there an example of how to do it in Boost? Thank you John Fletcher

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RTG Graph Generator
by Khaled Ammar 02 Feb '14

02 Feb '14

Hi everyone, I noticed that boost has RMAT and Erdös-Renyi graph generator but it does not include a (more) recent and realistic graph generator like RTG. RTG is based on this paper from CMU: http://www.cs.cmu.edu/~lakoglu/pubs/RTG_GraphGenerator.pdf. -- Thanks, -Khaled

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