August 2009 - Boost - lists.preview.boost.org

Checking for return type -- BOOST_STATIC_ASSERT?
by Edward Grace 21 Aug '09

21 Aug '09

I'd like to be able to make certain that a function/functor returns a double precision floating point value. I was always under the impression that it's essentially impossible to check things based on return type. Is there a way to do this? Something like BOOST_STATIC_ASSERT, who knows perhaps that *can* do it.. Ideally I would like to have some sort of compile type warning so that in the following context, class myclass { public: ... template <class O> a_func(O functor) { ASSERT_IS_A_FUNCTOR(O); ASSERT_RETURN_TYPE_CONVERTABLE_TO_FLOAT(O); } }; if O is compatible with the concept of a functor and O returns a type that can be converted to a float, then we are good to go -- otherwise I'd like an intelligible error. If, for example, O is of the type 'void (*)()' I'd like it (the compiler) to spit out, "The function pointer of type O must of signature float (*)()" Any ideas? -ed ------------------------------------------------ "No more boom and bust." -- Dr. J. G. Brown, 1997

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Re: [boost] [interprocess] SHARING_VIOLATION due to antivirus
by raindog＠macrohmasheen.com 21 Aug '09

21 Aug '09

I can confirm that I received your message twice. ------Original Message------ From: Isidor Zeuner Sender: boost-bounces(a)lists.boost.org To: boost(a)lists.boost.org ReplyTo: boost(a)lists.boost.org Sent: Aug 20, 2009 9:21 PM Subject: Re: [boost] [interprocess] SHARING_VIOLATION due to antivirus > Quoting Lars Hagstrom <lars(a)update.uu.se>: > > > Yes, of course it is due to bad AV. But for me it would still be handy > > if boost.interprocess was a little bit more tolerant towards that. If my > > software crashes it will be perceived as buggy, however much I blame AV... > > One thing you can do is to, at startup, detect if nod32.dll is loaded in your > process, and throw up a warning dialog to tell the user that the AV software is > buggy. > This seems inappropriate since, if anything, the operating system kernel which forces user space programmers into busy waiting for obtaining locks could be considered buggy by design in that regard. However, this bug could even be warned about at compile time, so we could solve this in boost itself. It is probably inappropriate to do so by default, but for administrators of heterogenous systems it might become handy to have a preprocessor flag which can warn if someone is about to deploy software which uses features the operating system was not designed for, so it can be considered to move the application to a more appropriate platform. Best regards, Isidor PS: The moderation software of this list seems to be broken. I sent this message before, received a "...was successfully received by the Boost mailing list" acknowledgement after a while, but over 12 hours later the message is still neither "successfully received", nor have I got any new status information. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost Sent from my Verizon Wireless BlackBerry

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[interprocess] SHARING_VIOLATION due to antivirus
by Lars Hagstrom 21 Aug '09

21 Aug '09

Hi, I've discovered that there is some unfortunate interaction of boost::interprocess and at least one antivirus product (ESET Nod32). The problem manifests on some installations, and the symptom is that an interprocess_exception with a native error code of 32 (ERROR_SHARING_VIOLATION) occurs when a named_semaphore (or other named objects) are opened (well, I've only seen it when opening, but depending on the AV product I guess it may happen when creating as well). Googling a bit on this I found http://support.microsoft.com/kb/316609, which suggests that AV products take exclusive locks on files just as a file is being opened, which sometimes upsets calls to CreateFile. What they suggest is doing retries when a sharing violation occurs. I'm not really saying that this is a boost.interprocess bug, but at least for me it would be handy if it was a little bit more tolerant towards AV products. I've managed (after quite a lot of hard work) to get a test environment where I can reproduce this quite easily, so I'm more than willing to help out with testing. Cheers Lars

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ABI Compliance checker
by Neal Becker 20 Aug '09

20 Aug '09

I wonder if something like this could be added to boost release process to warn of incompatibilities? http://ispras.linux-foundation.org/index.php/ABI_compliance_checker

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[ptr_container] new_clone overload
by Frank Mori Hess 20 Aug '09

20 Aug '09

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I've noticed that ptr_container/clone_allocator.hpp contains an undocumented overload of new_clone that accepts a pointer-to-const: template< class T > inline T* new_clone( const T* r ); It is annoying because it doesn't support a pointer-to-non-const argument, resulting in a compile error if you try. Any chance one of the following could be done? 1) remove it 2) add a pointer-to-non-const overload 3) change it to template< class T > T* new_clone( T* r ); 4) or if you care about always returning a pointer-to-non-const change it to template< class T > typename remove_const<T>::type * new_clone( T* r ); -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkpxsyoACgkQ5vihyNWuA4WnCACgwzxlNxG8z8NAln6Ra8+fNHsn Yr8AoL5a8Bdvkoya1p99GcS1W8N2WSjk =rSZQ -----END PGP SIGNATURE-----

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Review Wizard Status Report for June 2009
by Ronald Garcia 20 Aug '09

20 Aug '09

============================================== Review Wizard Status Report for June 2009 ============================================== News ==== Futures: Williams variant Accepted; Gaskill variant Rejected Boost 1.38 Released New Libraries: Revised Libraries: Boost.Range Extension Accepted Polynomial Library Rejected Boost 1.39 Released Constrained Value Review - Review Result Pending Older Issues ============ The Time Series Library, accepted in August 2007, has not yet been submitted to SVN. Eric Niebler and John Phillips are working on making the changes suggested during the review. The Floating Point Utilities Library, has not yet been submitted to SVN. It is slated to be integrated with the Boost.Math library. The Switch Library, accepted provisionally in January 2008, has not yet been submitted for mini-review and full acceptance. The Phoenix Library, accepted provisionally in September 2008, has not yet been submitted for mini-review and full acceptance. A rewrite of Phoenix, basing it on the Proto metaprogramming library, has just begun. General Announcements ===================== As always, we need experienced review managers. The review queue has been growing substantially but we have had few volunteers, so manage reviews if possible and if not please make sure to watch the review schedule and participate. Please take a look at the list of libraries in need of managers and check out their descriptions. In general review managers are active boost participants or library contributors. If you can serve as review manager for any of them, email Ron Garcia or John Phillips, "garcia at osl dot iu dot edu" and "phillips at mps dot ohio-state dot edu" respectively. We are also suffering from a lack of reviewers. While we all understand time pressures and the need to complete paying work, the strength of Boost is based on the detailed and informed reviews submitted by you. A recent effort is trying to secure at least five people who promise to submit reviews as a precondition to starting the review period. Consider volunteering for this and even taking the time to create the review as early as possible. No rule says you can only work on a review during the review period. A link to this report will be posted to www.boost.org. If you would like us to make any modifications or additions to this report before we do that, please email Ron or John. If you're a library author and plan on submitting a library for review in the next 3-6 months, send Ron or John a short description of your library and we'll add it to the Libraries Under Construction below. We know that there are many libraries that are near completion, but we have hard time keeping track all of them. Please keep us informed about your progress. Review Queue ============ * Lexer * Shifted Pointer * Logging * Log * Join * Pimpl * Thread Pool * Endian * Meta State Machine * Conversion * Sorting * GIL.IO * AutoBuffer * String Convert -------------------- Lexer ----- :Author: Ben Hanson :Review Manager: Eric Neibler :Download: `Boost Vault <http://boost-consulting.com/vault/index.php?action=downloadfile&filename=bo… >`__ :Description: A programmable lexical analyser generator inspired by 'flex'. Like flex, it is programmed by the use of regular expressions and outputs a state machine as a number of DFAs utilising equivalence classes for compression. Shifted Pointer --------------- :Author: Phil Bouchard :Review Manager: Needed :Download: `Boost Vault <http://www.boost-consulting.com/vault/index.php?&direction=0&order=&directo… >`__ :Description: Smart pointers are in general optimized for a specific resource (memory usage, CPU cycles, user friendliness, ...) depending on what the user need to make the most of. The purpose of this smart pointer is mainly to allocate the reference counter (or owner) and the object itself at the same time so that dynamic memory management is simplified thus accelerated and cheaper on the memory map. Logging ------- :Author: John Torjo :Review Manager: Gennadiy Rozental :Download: http://torjo.com/log2/ :Description: Used properly, logging is a very powerful tool. Besides aiding debugging/testing, it can also show you how your application is used. The Boost Logging Library allows just for that, supporting a lot of scenarios, ranging from very simple (dumping all to one destination), to very complex (multiple logs, some enabled/some not, levels, etc). It features a very simple and flexible interface, efficient filtering of messages, thread-safety, formatters and destinations, easy manipulation of logs, finding the best logger/filter classes based on your application's needs, you can define your own macros and much more! Log --- :Author: Andrey Semashev :Review Manager: Needed :Download: `Boost Vault <http://tinyurl.com/cm9lum>`__ :Description: The library is aimed to help adding logging features to applications. It provides out-of-box support for many widely used capabilities, such as formatting and filtering based on attributes, sending logs to a syslog server or to Windows Event Log, or simply storing logs into files. It also provides basic support for the library initialization from a settings file. The library can also be used for a wider range of tasks and implement gathering and processing statistical information or notifying user about application events. Join ---- :Author: Yigong Liu :Review Manager: Needed :Download: http://channel.sourceforge.net/ :Description: Join is an asynchronous, message based C++ concurrency library based on join calculus. It is applicable both to multi-threaded applications and to the orchestration of asynchronous, event-based applications. It follows Comega's design and implementation and builds with Boost facilities. It provides a high level concurrency API with asynchronous methods, synchronous methods, and chords which are "join-patterns" defining the synchronization, asynchrony, and concurrency. Pimpl ----- :Author: Vladimir Batov :Review Manager: Needed :Download: | `Boost Vault <http://www.boost-consulting.com/vault/index.php?action=downloadfile&filenam… >`__ | http://www.ddj.com/cpp/205918714 (documentation) :Description: The Pimpl idiom is a simple yet robust technique to minimize coupling via the separation of interface and implementation and then implementation hiding. This library provides a convenient yet flexible and generic deployment technique for the Pimpl idiom. It's seemingly complete and broadly applicable, yet minimal, simple and pleasant to use. Thread Pool ----------- :Author: Oliver Kowalke :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo… >`__ :Description: The library provides: - thread creation policies: determines the management of worker threads: - fixed set of threads in pool - create workerthreads on demand (depending on context) - let worker threads ime out after certain idle time - channel policies: manages access to queued tasks: - bounded channel with high and low watermark for queuing tasks - unbounded channel with unlimited number of queued tasks - rendezvous syncron hand-over between producer and consumer threads - queueing policy: determines how tasks will be removed from channel: - FIFO - LIFO - priority queue (attribute assigned to task) - smart insertions and extractions (for instance remove oldest task with certain attribute by newst one) - tasks can be chained and lazy submit of taks is also supported (thanks to Braddocks future library). - returns a task object from the submit function. The task it self can be interrupted if its is cooperative (means it has some interruption points in its code -> ``this_thread::interruption_point()`` ). Endian ------ :Author: Beman Dawes :Review Manager: Needed :Download: http://mysite.verizon.net/beman/endian-0.10.zip :Description: Header boost/integer/endian.hpp provides integer-like byte-holder binary types with explicit control over byte order, value type, size, and alignment. Typedefs provide easy-to-use names for common configurations. These types provide portable byte-holders for integer data, independent of particular computer architectures. Use cases almost always involve I/O, either via files or network connections. Although data portability is the primary motivation, these integer byte- holders may also be used to reduce memory use, file size, or network activity since they provide binary integer sizes not otherwise available. Meta State Machine ------------------ :Author: Christophe Henry :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?direction=0&order=&director… >`__ :Description: Msm is a framework which enables you to build a Finite State Machine in a straightforward, descriptive and easy-to-use manner . It requires minimal effort to generate a working program from an UML state machine diagram. This work was inspired by the state machine described in the book of David Abrahams and Aleksey Gurtovoy "C++ Template Metaprogramming" and adds most of what UML Designers are expecting from an UML State Machine framework: * Entry and Exit Methods * Guard Conditions * Sub state machines (also called composite states in UML) * History * Terminate Pseudo-State * Deferred Events * Orthogonal zones * Explicit entry into sub state machine states * Fork * Entry / Exit pseudo states * Conflicting transitions Conversion ---------- :Author: Vicente Botet :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=co… >`__ :Description: Generic explicit conversion between unrelated types. Boost.Conversion provides: * a generic ``convert_to`` function which can be specialized by the user to make explicit conversion between unrelated types. * a generic ``assign_to`` function which can be specialized by the user to make explicit assignation between unrelated types. * conversion between ``std::complex`` of explicitly convertible types. * conversion between ``std::pair`` of explicitly convertible types. * conversion between ``boost::optional`` of explicitly convertible types. * conversion between ``boost::rational`` of explicitly convertible types. * conversion between ``boost::interval`` of explicitly convertible types. * conversion between ``boost::chrono::time_point`` and ``boost::ptime``. * conversion between ``boost::chrono::duration`` and ``boost::time_duration``. Sorting ------- :Author: Steven Ross :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=al… >`__ :Description: A grouping of 3 templated hybrid radix/comparison-based sorting algorithms that provide superior worst-case and average-case performance to std::sort: integer_sort, which sorts fixed-size data types that support a rightshift (default of >>) and a comparison (default of <) operator. float_sort, which sorts standard floating-point numbers by safely casting them to integers. string_sort, which sorts variable-length data types, and is optimized for 8-bit character strings. All 3 algorithms have O(n(k/s + s)) runtime where k is the number of bits in the data type and s is a constant, and limited memory overhead (in the kB for realistic inputs). In testing, integer_sort varies from 35% faster to 8X as fast as std::sort, depending on processor, compiler optimizations, and data distribution. float_sort is roughly 7X as fast as std::sort on x86 processors. string_sort is roughly 2X as fast as std::sort. GIL.IO ------ :Author: Christian Henning :Review Manager: Needed :Download: `GIL Google Code Vault <http://gil-contributions.googlecode.com/files/rc2.zip >`__ :Description: I/O extension for ``boost::gil`` which allows reading and writing of/in various image formats ( tiff, jpeg, png, etc ). This review will also include the Toolbox extension which adds some common functionality to gil, such as new color spaces, algorithms, etc. AutoBuffer ---------- :Author: Thorsten Ottosen :Review Manager: Needed :Download: `Here <http://www.cs.aau.dk/~nesotto/boost/ auto_buffer.zip>`__ :Description: Boost.AutoBuffer provides a container for efficient dynamic, local buffers. Furthermore, the container may be used as an alternative to std::vector, offering greater flexibility and sometimes better performance. String Convert -------------- :Author: Vladimir Batov :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo… >`__ :Description: The library takes the approach of boost::lexical_cast in the area of string-to-type and type-to-string conversions, builds on the past boost::lexical_cast experience and advances that conversion functionality further to additionally provide: * throwing and non-throwing conversion-failure behavior; * support for the default value to be returned when conversion fails; * two types of the conversion-failure check -- basic and better/safe; * formatting support based on the standard I/O Streams and the standard (or user-defined) I/O Stream-based manipulators (like std::hex, std::scientific, etc.); * locale support; * support for boost::range-compliant char and wchar_t-based string containers; * no DefaultConstructibility requirement for the Target type; * consistent framework to uniformly incorporate any type-to-type conversions. It is an essential tool with applications making extensive use of configuration files or having to process/prepare considerable amounts of data in, say, XML, etc. Libraries under development =========================== Please let us know of any libraries you are currently developing that you intend to submit for review. Mirror ------ :Author: Matus Chochlik :Download: | http://svn.boost.org/svn/boost/sandbox/mirror/doc/index.html | `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=mi… >`__ :Description: The aim of the Mirror library is to provide useful meta-data at both compile-time and run-time about common C++ constructs like namespaces, types, typedef-ined types, classes and their base classes and member attributes, instances, etc. and to provide generic interfaces for their introspection. Mirror is designed with the principle of stratification in mind and tries to be as less intrusive as possible. New or existing classes do not need to be designed to directly support Mirror and no Mirror related code is necessary in the class' definition, as far as some general guidelines are followed Most important features of the Mirror library that are currently implemented include: * Namespace-name inspection. * Inspection of the whole scope in which a namespace is defined * Type-name querying, with the support for typedef-ined typenames and typenames of derived types like pointers, references, cv-qualified types, arrays, functions and template names. Names with or without nested-name-specifiers can be queried. * Inspection of the scope in which a type has been defined * Uniform and generic inspection of class' base classes. One can inspect traits of the base classes for example their types, whether they are inherited virtually or not and the access specifier (private, protected, public). * Uniform and generic inspection of class' member attributes. At compile-time the count of class' attributes and their types, storage class specifiers (static, mutable) and some other traits can be queried. At run-time one can uniformly query the names and/or values (when given an instance of the reflected class) of the member attributes and sequentially execute a custom functor on every attribute of a class. * Traversals of a class' (or generally type's) structure with user defined visitors, which are optionally working on an provided instance of the type or just on it's structure without any run-time data. These visitors are guided by Mirror through the structure of the class and optionally provided with contextual information about the current position in the traversal. I'm hoping to have it review ready in the next few months. Interval Template Library ------------------------- :Author: Joachim Faulhaber :Description: The Interval Template Library (Itl) provides intervals and two kinds of interval containers: Interval_sets and interval_maps. Interval_sets and maps can be used just as sets or maps of elements. Yet they are much more space and time efficient when the elements occur in contiguous chunks: intervals. This is obviously the case in many problem domains, particularly in fields that deal with problems related to date and time. Interval containers allow for intersection with interval_sets to work with segmentation. For instance you might want to intersect an interval container with a grid of months and then iterate over those months. Finally interval_maps provide aggregation on associated values, if added intervals overlap with intervals that are stored in the interval_map. This feature is called aggregate on overlap. It is shown by example: :: typedef set<string> guests; interval_map<time, guests> party; guests mary; mary.insert("Mary"); guests harry; harry.insert("Harry"); party += make_pair(interval<time>::rightopen(20:00, 22:00),mary); party += make_pair(interval<time>::rightopen_(21:00, 23:00),harry); // party now contains [20:00, 21:00)->{"Mary"} [21:00, 22:00)->{"Harry","Mary"} //guest sets aggregated on overlap [22:00, 23:00)->{"Harry"} As can be seen from the example an interval_map has both a decompositional behavior (on the time dimension) as well as a accumulative one (on the associated values). StlConstantTimeSize ------------------- :Author: Vicente J. Botet Escriba :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=consta… >`__ :Description: Boost.StlConstantTimeSize Defines a wrapper to the stl container list giving the user the chioice for the complexity of the size function: linear time, constant time or quasi-constant. In future versions the library could include a similar wrapper to slist. InterThreads ------------------- :Author: Vicente J. Botet Escriba :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=in… >`__ :Description: Boost.InterThreads extends Boost.Threads adding some features: * thread decorator: thread_decorator allows to define setup/cleanup functions which will be called only once by thread: setup before the thread function and cleanup at thread exit. * thread specific shared pointer: this is an extension of the thread_specific_ptr providing access to this thread specific context from other threads. As it is shared the stored pointer is a shared_ptr instead of a raw one. * thread keep alive mechanism: this mechanism allows to detect threads that do not prove that they are alive by calling to the keep_alive_point regularly. When a thread is declared dead a user provided function is called, which by default will abort the program. * thread tuple: defines a thread groupe where the number of threads is know statically and the threads are created at construction time. * set_once: a synchonizer that allows to set a variable only once, notifying to the variable value to whatever is waiting for that. * thread_tuple_once: an extension of the boost::thread_tuple which allows to join the thread finishing the first, using for that the set_once synchronizer. * thread_group_once: an extension of the boost::thread_group which allows to join the thread finishing the first, using for that the set_once synchronizer. (thread_decorator and thread_specific_shared_ptr) are based on the original implementation of threadalert written by Roland Schwarz. Boost.InterThreads extends Boost.Threads adding thread setup/cleanup decorator, thread specific shared pointer, thread keep alive mechanism and thread tuples.

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[shifted_ptr] Status
by Phil Bouchard 20 Aug '09

20 Aug '09

Greetings: More than a year ago I have submitted a quite stable version of the shifted_ptr memory manager. I am not aware of the level of understanding of it but I am planning writing more documentation, helping introducing it quicker. For now there is a quick presentation which can be found at: http://svn.boost.org/svn/boost/sandbox/shifted_ptr/libs/smart_ptr/doc/Shift… As far as I am concerned, I stepped into astrophysics and I wrote a book called "Finite Relativism" reengineering the whole relativity theory with standard calculus. This is out of topic for this list but I need writing a complex simulator so I will post on "user". Thank you, -Phil

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building a run-time static version
by Lorenzo Bettini 20 Aug '09

20 Aug '09

Hi I was trying to build a static version of the regex library (boost 1.39), issuing this command: ./bjam --build-dir=build_static --layout=system threading=single runtime-link=static link=static but I always get this error: error: link=shared together with runtime-link=static is not allowed error: such property combination is either impossible error: or too dangerious to be of any use but why is it trying to use link=shared when I explicitly specified link=static? thanks in advance Lorenzo -- Lorenzo Bettini, PhD in Computer Science, DI, Univ. Torino ICQ# lbetto, 16080134 (GNU/Linux User # 158233) HOME: http://www.lorenzobettini.it MUSIC: http://www.purplesucker.com http://www.myspace.com/supertrouperabba BLOGS: http://tronprog.blogspot.com http://longlivemusic.blogspot.com http://www.gnu.org/software/src-highlite http://www.gnu.org/software/gengetopt http://www.gnu.org/software/gengen http://doublecpp.sourceforge.net

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[flat_set/flat_map] request for new constructor that accepts a sorted sequence
by Thorsten Ottosen 20 Aug '09

20 Aug '09

Hi Ion, It would be veyr nice to have the following constructor: template< class Iter > flat_container( Iter, Iter, bool /*tag*/ ); which allows one to give the container an already sorted sequence (this would be the precondition). -Thorsten

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[spirit][karma] In-place modification of previously parsed content?
by Carlos Rafael Giani 19 Aug '09

19 Aug '09

Hello, I wonder if it is possible to modify previously parsed content using Karma. An example is some text like: coordinate (1, 4.15, 1.49, 0.81) // some comment 1 coordinate (1, -19, 4, -1) // some comment 2 Now suppose the numbers are all parsed, and I change the 0.81 to 71.44. I want to update the text accordingly: coordinate (1, 4.15, 1.49, 71.44) // some comment 2 coordinate (1, -19, 4, -1) // some comment 2 Note how the overall formatting and comments are preserved. The text could contain lots of other strings etc. and they would be all left untouched. This part - the preservation - is the hard one, and I ask, is this possible using Karma?

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[1.40.0] Beta 1 available
by Beman Dawes 19 Aug '09

19 Aug '09

Boost release 1.40.0 beta 1 is available from SourceForge: http://sourceforge.net/projects/boost/files/ This release contains no new libraries, but contains numerous bug fixes for existing libraries. Boost source files with types .bz2 and .gz are created with POSIX-style (\n) line endings. Source files with types .7z and .zip are created with Windows-style (\r\n) line endings. The content is otherwise identical. Be sure to download a file with the appropriate line endings for your platform. If you are new to Boost, be sure to read the Getting Started Guide. See www.boost.org There are three known issues with beta 1: * boost/detail/scoped_enum_emulation.hpp, used by Boost.Filesystem, has a name conflict (enum_t) with Unix header rpc/types.h. Fixed in trunk, but not yet merged into the release. * Boost.Python has fixes in trunk not yet merged into to the release. * Boost.Signals has has fixes in trunk not yet merged into to the release. These issues will be resolved for the final 1.40.0 release. Other than these three known issues, please report any problems with the beta on the developers or users mailing lists. Unless unexpected problems arise, the plan is to ship the final 1.40.0 release in a week to ten days. Thanks, --The Boost release team

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FW: [boost.thread] how to delete this thread from within the thread and thread hangs
by Tan, Tom (Shanghai) 19 Aug '09

19 Aug '09

I debugged through VS2010, it seems that the main thread gets stuck in thread_group::join_all(), while some remaining thread gets stuck in remove_this_thread(). The state of the threads are wait:UserRequest. Does it suggest that a thread cannot be deleted(by operator delete) or removed from the thread_group(by remove_thread()) before the join_all() ? Thanks. -----Original Message----- From: Tan, Tom (Shanghai) Sent: 2009-08-19 10:35 To: 'boost(a)lists.boost.org' Subject: [boost.thread] how to delete this thread from within the thread and thread hangs I am using boost::thread_group to create(using thread_group::create_thread()) and dispatch threads. In order to limit the max thread numbers, at the end of each thread, I remove the thread from the thread_group and delete the thread itself(so that I could decide whether new threads need to be created). However it hangs somewhere between the creation and deletion of the last thread (say the 999th one of 999 in total). My questions are: -1) is it OK to delete the thread from within itself like what I do? if not, what the best way to achieve this -2) why does my code hangs? Below are the related code: //1- code to create and dispatch thread { //mutex for map<thread_id, thread*> operations boost::mutex::scoped_lock lk(m_mutex_for_ptr); // create a thread for this->f(duplicate_hashes) boost::thread* p = m_thread_group.create_thread(boost::bind( &detectiveT<equal_predicate>::f, this, duplicate_hashes )); // save the thread_id -> thread pointer map for later lookup and deletion m_thread_ptrs.insert(make_pair(p->get_id(), p)); // log to console for debug cout << "thread created: " << p->get_id() << ", " << m_thread_group.size() << ", " m_thread_ptrs.size() << "\n"; } //2- code of the thread execution void f(list<map_iterator_type>& l) { Do_something(l); boost::this_thread::at_thread_exit(boost::bind( &detectiveT<equal_predicate>::remove_this_thread, this )); } //3- code to delete the thread itself void remove_this_thread() { { //mutex for map<thread_id, thread*> operations boost::mutex::scoped_lock lk(m_mutex_for_ptr); boost::thread::id this_id(boost::this_thread::get_id()); map<boost::thread::id, boost::thread*>::iterator itr; itr = (m_thread_ptrs.find(this_id)); if(m_thread_ptrs.end() != itr) { // remove it from the control of thread_group m_thread_group.remove_thread(itr->second); // delete it delete itr->second; // remove from the map m_thread_ptrs.erase(this_id); // log to console for debug cout << "thread erased: " << this_id << ", " << m_thread_group.size() << ", " << m_thread_ptrs.size() << "\n"; } } } Thanks.

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[boost.thread] how to delete this thread from within the thread and thread hangs
by Tan, Tom (Shanghai) 19 Aug '09

19 Aug '09

I am using boost::thread_group to create(using thread_group::create_thread()) and dispatch threads. In order to limit the max thread numbers, at the end of each thread, I remove the thread from the thread_group and delete the thread itself(so that I could decide whether new threads need to be created). However it hangs somewhere between the creation and deletion of the last thread (say the 999th one of 999 in total). My questions are: -1) is it OK to delete the thread from within itself like what I do? if not, what the best way to achieve this -2) why does my code hangs? Below are the related code: //1- code to create and dispatch thread { //mutex for map<thread_id, thread*> operations boost::mutex::scoped_lock lk(m_mutex_for_ptr); // create a thread for this->f(duplicate_hashes) boost::thread* p = m_thread_group.create_thread(boost::bind( &detectiveT<equal_predicate>::f, this, duplicate_hashes )); // save the thread_id -> thread pointer map for later lookup and deletion m_thread_ptrs.insert(make_pair(p->get_id(), p)); // log to console for debug cout << "thread created: " << p->get_id() << ", " << m_thread_group.size() << ", " m_thread_ptrs.size() << "\n"; } //2- code of the thread execution void f(list<map_iterator_type>& l) { Do_something(l); boost::this_thread::at_thread_exit(boost::bind( &detectiveT<equal_predicate>::remove_this_thread, this )); } //3- code to delete the thread itself void remove_this_thread() { { //mutex for map<thread_id, thread*> operations boost::mutex::scoped_lock lk(m_mutex_for_ptr); boost::thread::id this_id(boost::this_thread::get_id()); map<boost::thread::id, boost::thread*>::iterator itr; itr = (m_thread_ptrs.find(this_id)); if(m_thread_ptrs.end() != itr) { // remove it from the control of thread_group m_thread_group.remove_thread(me); // delete it delete itr->second; // remove from the map m_thread_ptrs.erase(this_id); // log to console for debug cout << "thread erased: " << this_id << ", " << m_thread_group.size() << ", " << m_thread_ptrs.size() << "\n"; } } } Thanks.

1 0

Introduction
by Jeff 18 Aug '09

18 Aug '09

Hey everyone. I'm Jeff Gosling and been deving in C++ for 8+ years now and I'm looking to get involved in an open source community I am very interested in getting involved in Boost development. I've subscribed to the developer mailing list and have browsed through the community webpage. I've also read up on all the existing boost modules/projects. Obviously I have a bit more reading to do to get to grips with Boost. What I was wondering is how specifically can I help? Where is a good place for someone new to Boost to start? Is there a task list that I can look to for something new to do? Thanks, Jeff

2 1

[1.40.0] Beta 1 release candidate available
by Beman Dawes 18 Aug '09

18 Aug '09

1.40.0 beta 1 release candidates are available at http://boost.cowic.de/rc/ Before pushing the beta out to SourceForge, I'd appreciate it if several people would try the release candidate and report success or problems. Thanks, --Beman

12 29

boost build output locations
by Zachary Turner 18 Aug '09

18 Aug '09

I notice there's some strange asymmetries in the locations that the standard boost build process outputs binaries to. Is there a reason for this? For example, running bjam variant=debug,release address-model=32 I get the following directory structure: bin.v2 --libs ----date_time\build\msvc-9.0 ------debug --------address-model-32 ---------- boost_date_time-vc90-gd-1_39.dll ---------- boost_date_time-vc90-gd-1_39.lib ----------link-static ------------threading-multi -------------- libboost_date_time-vc90-mt-gd-1_39 Alright there is one asymmetry evident. The dll version of the binaries are in address-model-32, and the static library version of the binaries are in address-model-32/link-static/threading-multi. Should there be like a link-dynamic and a link-static? It makes it much easier to automate linking and building if everything is symmetric, because in some compilers (e.g. visual studio) you don't have as much control as you do with a makefile. So then we take a look at boost::thread bin.v2 --libs ----date_time\build\msvc-9.0 ------debug --------address-model-32 ----------link-static ------------threading-multi -------------- libboost_thread-vc90-mt-gd-1_39.lib ----------threading-multi ------------ boost_thread-vc90-mt-gd-1_39.lib ------------ boost_thread-vc90-mt-gd-1_39.dll This time, the dll versions appeared under address-model-32/threading-multi instead of just address-model-32 like in date_time. Am I going crazy and I have a messed up system, or is this just the way it is? Is it easy to change, or would it be undesirable to change for some reason? Zach

2 1

[move][container] Fast-track reviews for Move and Container?
by Ion Gaztañaga 17 Aug '09

17 Aug '09

Hi, As some others have mentioned, I'd like to ask if Boost.Move and Boost.Container could meet the requirements for a Fast Track review (the Review Wizard has the last word according to the Boost Formal Process, but I'll like to see if there is consensus). Arguments: Boost.Move -> Only one header (move.hpp) -> Technique already in use in Boost (in several detail namespaces). This is a proposal for a common implementation. -> Boost-conformant implementation available in sandbox. Boost.Container -> Most of them standard containers -> Node containers are just wrappers over Boost.Intrusive -> Most containers (all except stable_vector) were already reviewed for Boost.Interprocess. -> Boost-conformant implementation available in sandbox. I'll be specially interested in pushing Move first, so that we could have move semantics for Boost 1.41. Best, Ion

4 6

Re: [boost] [1.40.0] Unmerged changes delaying beta 1
by Ralf W. Grosse-Kunstleve 17 Aug '09

17 Aug '09

> I'd prefer these changes go in 1.40.0 if possible. Since they have > been stable on trunk, and we are waiting a few more days anyhow for > beta feedback, I don't see a lot of risk. So please merge, and then > watch the release tests to make sure nothing breaks. All {boost,libs}/python changes are now merged into the release branch. Thanks to Steven Watanabe and Henrik Sundberg for pointing out the http vs. https problem. Ralf

1 0

Re: [boost] [1.40.0] need svn merge advice (was: Unmerged changes delaying beta 1)
by Ralf W. Grosse-Kunstleve 17 Aug '09

17 Aug '09

Beman gave me the advice below. When trying to svn merge libs/python I'm running into this error: svn: Access scheme mixtures not yet supported ('http://svn.boost.org/svn/boost/trunk/libs/python/test/enable_shared_from_th…' and 'https://svn.boost.org/svn/boost/branches/release/libs/python/test') svn: Error reading spooled REPORT request response The full output is below. Fedora release 11 (Leonidas) % svn --version svn, version 1.6.4 (r38063) compiled Aug 7 2009, 03:42:39 The working copy was checked out fresh with this client. The merge command is OK for boost/python. Adding --force doesn't help for libs/python. Last night I locally tested after simply copying the boost/python and libs/python directories into a working copy of the release branch. That works fine, but there will be no merge info if I commit from the manually modified working copy. IIUC that will be a problem for future merges. What's the best way forward? What if I commit from the release working copy with the manual copies from the trunk, then manually edit svn:mergeinfo to tell it I have everything from trunk up to this point? -- Secondary question: should I do this at the top level (branches/release) or in the subdirectories (branches/release/boost/python, branches/release/libs/python)? Any advice is appreciated; I'm quite afraid of doing something bad to the merge info. (The svn documentation explicitly tells me not to merge in subdirectories in order to avoid pitfalls...) Ralf ----- Original Message ---- From: Beman Dawes <bdawes(a)acm.org> To: Ralf W. Grosse-Kunstleve <rwgk(a)yahoo.com> Sent: Monday, August 17, 2009 9:12:37 AM Subject: Re: [boost] [1.40.0] Unmerged changes delaying beta 1 I'd prefer these changes go in 1.40.0 if possible. Since they have been stable on trunk, and we are waiting a few more days anyhow for beta feedback, I don't see a lot of risk. So please merge, and then watch the release tests to make sure nothing breaks. > (I don't have any experience working with the release branch...) The merge process is pretty simple. Assume you have a working copy of branches release at \boost\release: svn merge http://svn.boost.org/svn/boost/branches/release/boost/python \ http://svn.boost.org/svn/boost/trunk/boost/python \ \boost\release\boost\python svn merge http://svn.boost.org/svn/boost/branches/release/libs/python \ http://svn.boost.org/svn/boost/trunk/libs/python \ \boost\release\libs\python % svn merge --force http://svn.boost.org/svn/boost/branches/release/libs/python http://svn.boost.org/svn/boost/trunk/libs/python /net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python --- Merging differences between repository URLs into '/net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python': U /net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python/test/andreas_beyer.cpp U /net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python/test/stl_iterator.py U /net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python/test/exec.cpp U /net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python/test/slice.cpp U /net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python/test/object.cpp U /net/firtree/raid1/rwgk/boost_release_merge_attempt/boost/libs/python/test/enum.py svn: Access scheme mixtures not yet supported ('http://svn.boost.org/svn/boost/trunk/libs/python/test/enable_shared_from_th…' and 'https://svn.boost.org/svn/boost/branches/release/libs/python/test') svn: Error reading spooled REPORT request response

3 2

[C++0x] Report from Frankfurt committee meeting
by Beman Dawes 17 Aug '09

17 Aug '09

The C++ standards committee met in Frankfurt, Germany, last week. Key actions: * Concepts have been removed from C++0x. The committee is very much in favor of Concepts. But Concepts are seen as so important that they have to be right. And the strong consensus was that getting Concepts right, for any reasonable definition of "right", would add several years to the schedule. There was also a consensus that an implementation of a compiler that could compile the entire standard library is part of the definition of "right". While ConceptGCC has been a great help, it isn't there as far as validating "right". Personally, I think Clang may end up being the compiler that eventually validates Concepts. * The range-based for loop and some other library features that were dependent on Concepts will be retained by recasting them to no longer depend on Concepts. See a paper in the upcoming post-meeting mailing to see how range-based for loops will work. * A second Committee Draft (CD2) will need go out for public comment in the Spring or Summer 2010, given the amount of change required to remove Concepts. The C++0x final schedule will thus slip about one year. * No committee action was taken as to how Concepts will eventually make it into C++. While there was a bit of discussion about doing a Concepts Technical Report (TR), there was no such proposal made. Committee members seem to lean toward letting the two rival Concept teams go back to work outside of the committee process. The expectation being they will come back to the committee when they are ready to restart the standardization process. Hopefully the lessons learned about Concepts during the committee process will be taken advantage of, so future standardization of Concepts will be smoother. My personal opinion is that removing Concepts will speed the arrival of conforming C++0x compilers. GCC, for example, has already implemented much of C++0x, so their key developers are no longer faced with the difficult task of turning ConceptGCC into a production compiler, and can concentrate on remaining major features like lambdas. Although Concepts would have added a lot to C++ and Boost, Concepts would also have presented major migration challenges. I'm thinking that for most Boost libraries, migration to C++0x will now be easier and less disruptive. We need to focus on the bright side. --Beman

18 35

boost.lockfree review request
by Tim Blechmann 17 Aug '09

17 Aug '09

hi all, i would like to submit a small library of lock-free data structures for review. boost.lockfree provides implementations of lock-free data structures. lock-free data structures can be accessed by multiple threads without the necessity of blocking synchronization primitives such as guards. lock-free data structures can be used in real-time systems, where blocking algorithms may lead to high worst-case execution times, to avoid priority inversion, or to increase the scalability for multi-processor machines. boost.lockfree provides: * boost::lockfree::fifo, a lock-free fifo queue * boost::lockfree::stack, a lock-free stack the code is available from the boost vault: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=boost_… and from my personal git repository: git://tim.klingt.org/boost_lockfree.git http://tim.klingt.org/git?p=boost_lockfree.git the documentation is available at: http://tim.klingt.org/boost_lockfree/ thanks in advance, tim -- tim(a)klingt.org http://tim.klingt.org You don't have to call it music if the term shocks you. John Cage

1 0

[1.40.0] Unmerged changes delaying beta 1
by Beman Dawes 17 Aug '09

17 Aug '09

There seem to be a large number of changes to trunk that have not been merged into branches/release. Perhaps a lot of merges were forgotten after the bug fixing sprint. All of the libraries listed below are suspect, although some may just be holding changes until after the release. "svn diff" can be used to see exactly what changes have not been merged. Here is a simple Windows batch file that eases typing; perhaps someone could post a Unix equivalent. @echo off if not %1$==$ goto usage_ok echo Usage: unmerged library-name goto done :usage_ok svn diff %2 %3 %4 %5 %6 http://svn.boost.org/svn/boost/branches/release/boost/%1.hpp http://svn.boost.org/svn/boost/trunk/boost/%1.hpp svn diff %2 %3 %4 %5 %6 http://svn.boost.org/svn/boost/branches/release/boost/%1 http://svn.boost.org/svn/boost/trunk/boost/%1 svn diff %2 %3 %4 %5 %6 http://svn.boost.org/svn/boost/branches/release/libs/%1 http://svn.boost.org/svn/boost/trunk/libs/%1 :done If your library has changes that need to be merged, please do so right away. I'll hold off on the beta until Monday morning to give folks a chance to do merges and let tests cycle. --Beman accumulators algorithm any array asio assign bimap bind circular_buffer compatibility concept concept_check config conversion crc date_time detail disjoint_sets dynamic_bitset exception flyweight foreach format function function_types functional fusion gil graph integer io iostreams iterator lambda math mpi mpl multi_array multi_index numeric optional parameter pool preprocessor program_options property_map proto ptr_container python random range rational regex scope_exit serialization signals smart_ptr spirit statechart static_assert system thread timer tokenizer tr tuple type_traits typeof units unordered utility variant wave xpressive

13 16

[bgl] Transitive closure
by Gustavo Gutiérrez 14 Aug '09

14 Aug '09

Hello, I am trying to compute the transitive closure of a graph. The definition of the graph is: typedef boost::adjacency_list<boost::vecS, boost::listS, boost::bidirectionalS, boost::property<boost::vertex_name_t, int> > graph_t; The code that calls the transitive closure function is: (g is of type graph_t) // prepare a map Vertex-int. map<Vertex,int> extmap; VertexIt vi, v_end; int i = 0; for (tie(vi,v_end) = vertices(g); vi != v_end; ++vi, i++) { extmap.insert(pair<Vertex,int>(*vi,i)); } associative_property_map<map<Vertex,int> > tempMap(extmap); map<Vertex,Vertex> vmap; adjacency_list<> c; boost::transitive_closure(g, c, vmap, tempMap); According with the documentation, tempMap must be a map from vertices to integers. When I try to compile the program, the following error occurs: /usr/local/include/boost/graph/transitive_closure.hpp:182: error: invalid initialization of reference of type 'const std::vector<long unsigned int, std::allocator<long unsigned int> >&' from expression of type 'std::vector<int, std::allocator<int> >' After taking a look at the file, the vector successors is defined as: std::vector<std::vector<cg_vertex> > successors(...); The error occurs with the following call: detail::union_successor_sets(successors[u], successors[v], successors[u]); the definition of union_successor_sets is: inline void union_successor_sets(const std::vector < std::size_t > &s1, const std::vector < std::size_t > &s2, std::vector < std::size_t > &s3) {...} Probably I am really wrong, but successors[u] is an std::vector<cg_vertex> and the function expects a std::vector < std::size_t >. So size_t and cg_vertex should be the same type, which according with the error reported by the compiler is not true. Can someone give me a hint on how to solve my problem? Thaks in advance.

2 2

stack-allocated STL-containers
by Stefan Strasser 13 Aug '09

13 Aug '09

I recently ran into the problem that a local container on the stack, which was likely to be very small, but its size was still not known at compile-time, consumed a considerable amount of runtime because of allocation/deallocation. e.g. void do(istream &i){ vector<int> vec; vec.reserve(20); while(...){ int tmp; i >> tmp; vec.push_back(tmp); } } so I wrote an allocator that I think is generally useful and could be added e.g. to Boost.Array: void do(int n){ int buffer[20]; stack_allocator<int,20> alloc(buffer); vector<int,stack_allocator<int,20> > vec(alloc); vec.reserve(alloc.max_stack_size()); while(...){ int tmp; i >> tmp; vec.push_back(tmp); } } the vector operates on the stack as long as there is enough space, and moves to the heap afterwards. in most cases there is no dynamic allocation. here's the source: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=stack_… it uses the simple_seq_fit allocation algorithm described here: http://www.boost.org/doc/libs/1_37_0/doc/html/interprocess/allocators_conta…

4 5

Generic copy-on-write infrastructure in boost?
by Jason Dictos 13 Aug '09

13 Aug '09

Hi, I'm looking for a way to implement a project using some copy-on-write feature, similar to how STL strings use reference counters to prevent needles copying of data. Is there anything in boost to help me out with this? -Jason ---------------------------------- Check out the Barracuda Spam & Virus Firewall - offering the fastest virus & malware protection in the industry: www.barracudanetworks.com/spam

5 7

[Serialization] Bizarre bug
by Jarl Lindrud 12 Aug '09

12 Aug '09

There is a rather bizarre bug in Boost.Serialization, that was reported on this list three years ago: http://article.gmane.org/gmane.comp.lib.boost.devel/147010/match=serializat… +bizarre+bug To sum up, a piece of code that is never even executed, is causing a serialization error in a different part of the program. Unfortunately it seems that this bug was never fixed - I just tried it on Boost 1.39.0, and the bug is still there. Any chance something can be done about it? For reference, here is the sample program that reproduces the issue: #include <sstream> #include <string> #include <vector> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/vector.hpp> template<typename Archive> struct X { template<typename T> void operator<<(const T &t) { Archive &archive = (*(Archive *) NULL); archive << t; } }; void dummy() { typedef boost::archive::text_oarchive Archive; X<Archive> &x = * (X<Archive> *) NULL; std::vector<char> *pt = NULL; // uncomment this line to cause the test in main() to fail //x << pt; } int main(int argc, char* argv[]) { std::vector<char> v0(25, '%'); std::vector<char> v1; std::ostringstream ostr; boost::archive::text_oarchive(ostr) & v0; std::istringstream istr(ostr.str()); boost::archive::text_iarchive(istr) & v1; bool ok = (v0 == v1); return 0; }

7 35

[mpl] strange vector_c and integral_c construction
by Maxim Yanchenko 12 Aug '09

12 Aug '09

Hi all, > Probably this is well-known and I just failed to find it in the docs and mailing list. According to the docs (http://www.boost.org/doc/libs/1_39_0/libs/mpl/doc/refmanual/integral-sequen…) typedef seq_c<T,c1,c2,... cn> s; Semantics: s is a sequence seq of integral constant wrappers integral_c<T,c1>, integral_c<T,c2>, ... integral_c<T,cn>. Consider the following example: const int64_t max_int = integer_traits<int>::const_max; const int64_t max_int_plus_1 = max_int + 1; BOOST_MPL_ASSERT(( equal< vector_c< int64_t, 1 > , vector< integral_c< int64_t, 1 > > > )); BOOST_MPL_ASSERT(( equal< vector_c< int64_t, max_int > , vector< integral_c< int64_t, max_int > > > )); BOOST_MPL_ASSERT(( equal< vector_c< int64_t, max_int_plus_1 > , vector< integral_c< int64_t, max_int_plus_1 > > > )); The first assert passes, while the second and third fail with the following error messages (removed repetition of 2147483647l for readability): test.h:149: error: ************mpl::equal<mpl::vector_c<int64_t, 2147483647l, 2147483647l, ...>, mpl::vector<mpl_::integral_c<int64_t, 2147483647>>, is_same<true> >::************' test.h:153: error: ************mpl::equal<mpl::vector_c<int64_t, -0x00000000080000000l, 2147483647l, ...>, mpl::vector<mpl_::integral_c<int64_t, 2147483648ll>>, is_same<true> >::************' I consider these errors as a contradiction to the docs statement. Probably, I configured MPL wrong, as I see in the preprocessed code, where long is used (boost/mpl/aux_/preprocessed/gcc/vector_c.hpp) template< typename T, long C0 = LONG_MAX, long C1 = LONG_MAX, long C2 = LONG_MAX , long C3 = LONG_MAX, long C4 = LONG_MAX, long C5 = LONG_MAX , long C6 = LONG_MAX, long C7 = LONG_MAX, long C8 = LONG_MAX , long C9 = LONG_MAX, long C10 = LONG_MAX, long C11 = LONG_MAX , long C12 = LONG_MAX, long C13 = LONG_MAX, long C14 = LONG_MAX , long C15 = LONG_MAX, long C16 = LONG_MAX, long C17 = LONG_MAX , long C18 = LONG_MAX, long C19 = LONG_MAX > struct vector_c; I'm using GCC 3.4.6, on Linux-64, compiling 32-bit binary (so int and long are of same size, and boost::int64_t is bigger than long). Thanks, Maxim (to reply in private, please use FirstName.LastName at gmail.com)

4 4

Microsoft Security Bulletin MS09-03: Vulnerabilities in Visual Studio Active Template Library Could Allow Remote Code Execution (969706)
by Christian Eckstein 12 Aug '09

12 Aug '09

Hi, I need to know the impact of the following security bulletin on Boost: Microsoft Security Bulletin MS09-03: Vulnerabilities in Visual Studio Active Template Library Could Allow Remote Code Execution (969706). I found usage of ATL only in the range and regex libraries and it seems that only string and array classes are used. None of the problematic methods seem to be used that are described in the checklist at http://msdn.microsoft.com/en-us/visualc/ee309358.aspx. - No class implements IUnknown so there is no ActiveX control. - No PROP_* macros are used - VT_* is not used - ReadFromStream is not used I think no modification of Boost and no recompilation of the Boost binaries is needed. I would be very happy if somebody could confirm this. Kind regards, Christian

2 1

persistence library proposal (with prototype implementation)
by Stefan Strasser 12 Aug '09

12 Aug '09

Is there any interest to include a persistence library in boost, built upon the boost serialization library? the basic idea is: transaction tx; change_objects(); tx.commit(); all changes made by change_objects() should be undone if tx is destroyed without calling commit(), e.g. because of an exception thrown by change_objects(). the library should provide ACID transaction properties, so that multiple transactions (in different threads) can work on the same objects and conflicts are discovered by the library. further, an application crash should be recovered, with the changes made by a transaction either committed as a whole or undone. to partition your object model into many different objects, which can be saved to disk and loaded back on demand, there is a new smart pointer introduced, which behaves like smart_ptr and is convertible to smart_ptr. objects that are handled by this smart pointer and are no longer used in memory are not destroyed but saved to disk. only objects which are no longer in use either in memory or on disk are destroyed. the only requirement on persistent objects would be to model the concept "Serializable" as defined by boost serialization. e.g. a linked list, whose elements are loaded from disk on demand could look like: struct node{ db_ptr<node> next; private: //Serializable requirements }; void traverse(){ while(current) current=current->next; //operator-> loads the next node } prototype implementation --- i've attached a test case using the current implementation. it demonstrates multiple concurrent transactions.running isolated from each other. it models a bank, with multiple threads constantly withdrawing from one (random) bank account and depositing the amount on another. when two threads are using the same bank account at the same time, resulting in money being lost, an isolation_exception is thrown in one of the threads and the transaction can be restarted. there is no manual thread synchronization involved. the current implementation uses an optimistic multiversion approach, meaning that each transaction running concurrently is working on its own copy of an object. when the transaction is committed conflicts are discovered and an isolation_exception is thrown. several things like reference counting on disk and the recovery process after a crash aren't implemented yet, but the basics are in place and should give you an idea of what kind of a library I'm proposing.

4 12

different matrix library?
by DE 12 Aug '09

12 Aug '09

hi i'm new to boost so please don't blame me the question is do you need a matrix library which allows you to write clear, human readable code like dV = (1/m)*force + transpose(A)*g - cross_product(omega, V) //here dV is a derivative of velocity, m is (scalar) mass //A is transition matrix and //g is gravity acceleration vector //omega is angular velocity and V is velocity vector itself //force is defined in body space (e.g. aerodynamics and thrust) that is an expression of newton's 2nd law (or if you like 'change in momentum' law: d(m*V)/dt = d_local(m*V)/dt + (omega)x(m*V) = sum_of(forces) as you can see so far i'm a math nerd) of course it must be implemented through lazy evaluation technique (which immediately implies expression templates) ps i looked at uBLAS and the design seemed obsolete to me so i thought there could be a better approach then blindly following blas design pps thanks for reading til here and forgive for (possibly) wasting your time

9 39

[Interprocess] Possible bug in shared memory on FreeBSD 8.0
by Manish Vachharajani 11 Aug '09

11 Aug '09

I've been happily using Boost.Interprocess to create shared memory regions under FreeBSD 7.2, however, I am having issues on FreeBSD 8.0 pre-release. I can reproduce the problem with Boost 1.39.0 and the svn trunk. The source of the problem appears to be that Boost.Interprocess calls lseek on a file descriptor returned by shm_open, but the results of such an lseek are undefined. Below, I explain further how I came to this conclusion. If you run the program I've appended to the end of this email, the constructor for managed_shared_memory throws an interprocess_exception with error code 29 which is Illegal Seek on FreeBSD. A little bit of system call tracing and debugging reveals that the offending seek is in mapped_region.h:447 (in svn revision 55512). However, digging around, it appears that lseek's behavior on file descriptors for shared memory regions is undefined (See http://www.opengroup.org/onlinepubs/000095399/functions/lseek.html for what IEEE 1003.1 standard has to say about this.) I've confirmed that FreeBSD 7.2 allowed such seeks but 8.0 does not by looking at the kernel source code. For what it's worth AIX 6.1 does not allow such seeks either (see http://publib.boulder.ibm.com/infocenter/systems/index.jsp?topic=/com.ibm.a…) Could someone advise me on what the correct fix for this bug is? I'd be glad to implement it, but I'm not sure what the right fix ought to be. #include <iostream> #include <string> #include <exception> #include <boost/interprocess/managed_shared_memory.hpp> namespace bip = boost::interprocess; int main(const int argc, const char *argv[]) { bool error = true; std::string shmName("testShmRegion"); bip::shared_memory_object::remove(shmName.c_str()); try { std::auto_ptr<bip::managed_shared_memory> segment(new bip::managed_shared_memory(bip::create_only, shmName.c_str(), 12345)); error = false; } catch(const std::exception &e) { std::cerr << "Error: " << e.what() << std::endl; } if(!error) { std::cout << "Shm allocated successfully." << std::endl; } return 0; } Manish

3 9

[asio] very confusing title
by DE 11 Aug '09

11 Aug '09

when i personally see 'asio' i immediately think about steinberg technology asio which stands for 'audio stream i/o' so it's up to you of course just want you to know

4 3

Vault access for Boost.Debug
by Zachary Turner 11 Aug '09

11 Aug '09

Hello, I'd like to request access to the vault. I'm going to upload a proof-of-concept of some of the things I mentioned earlier in my thread about Boost.Debug. This early version gives simple stack traces in limited scenarios, only supports Windows, and isn't designed very well. Here's an example of a program using it in its current form: void test_func(int argc, int argc2, char* argv[]) { stack_trace trace(10); //Maximum depth of 10 levels std::cout << trace.string() << std::endl; } int main(int argc, char* argv[]) { test_func(argc, argc, argv); return 0; } and an example of the stack trace printed as a result of this program: void test_func(int, int, char**) [f:/dev/stack_trace/main.cpp:10] int main(int, char**) [f:/dev/stack_trace/main.cpp:23] int __tmainCRTStartup() [f:/dd/vctools/crt_bld/self_x86/crt/src/crtexe.c:406] int mainCRTStartup() [f:/dd/vctools/crt_bld/self_x86/crt/src/crtexe.c:389] It also currently supports printing the names of all the arguments, but it was hackish and I left it out until it undergoes some redesign. There is currently no documentation, but as this is just a proof of concept I'm currently only looking for people to help out with actual code and/or provide input, so I think that's ok for now. Thanks

5 6

enum / string translation
by Zachary Turner 11 Aug '09

11 Aug '09

I wrote some code to perform both compile-time and runtime translation between enums and their corresponding string values. The only direction that isn't possible is string->enum at compile time. Is there any interest in this? You can use it as follows: typedef enum { ValueA1, ValueA2 } EnumA; typedef enum { ValueB1, ValueB2 } EnumB; BEGIN_ENUM_MAP_DECLS() BEGIN_ENUM_MAP(EnumA, a_map) ENUM_MAP(ValueA1) //maps ValueA1 to the string "ValueA1", provides both compile-time and run-time lookups. ENUM_MAP_NAME(ValueA2, "custom name") //maps ValueA2 to the string "custom name", provides both compile-time and run-time lookups END_ENUM_MAP() BEGIN_ENUM_MAP(EnumB, b_map) ENUM_MAP(ValueB1) ENUM_MAP(ValueB2) END_ENUM_MAP() END_ENUM_MAP_DECLS() void foo() { //value -> string, compile time BOOST_STATIC_ASSERT(enum_map<EnumA>::value_lookup[ValueA2] == "custom name"); //value -> string, runtime EnumB some_value = get_enum_b_from_external_source(); std::cout << "some_value = " << enum_map<EnumB>::name_lookup[some_value] << std::endl; //prints either 'some_value = ValueB1', or 'some_value = ValueB2' //string -> value, runtime EnumA value = enum_map<EnumA>::name_lookup["custom name"]; BOOST_ASSERT(value == ValueA2); } One particularly useful application of this that I've found is with regards to boost::program_options. You can provide an overload of boost::program_options::validate that uses boost::enable_if with boost::is_enum thus providing automatic support for entry of friendly names corresponding to enumerations on the command line or in a config file. Obviously there's many other easily identifiable uses as well. However, this is a common enough problem that I wonder if anyone else has already attempted something like this, and if so maybe I can look at their code first, or just scrap mine altogether and reuse something existing. If not, I'm sure there is plenty of room for improvement in mine but if it could fit somewhere in boost (perhaps boost/utility) I'd be willing to submit it and make necessary improvements. Unfortunately I don't think it's technically possible to have a simple syntax, even through preprocessor magic, that requires you to only specify the name of each enumerated value once, and end up providing both a definition of the enumeration as well as the mapping from string<->value, but if someone comes up with a way that would obviously be ideal.

7 16

[move] moving temporaries of copyable types
by klaus triendl 10 Aug '09

10 Aug '09

Hi, I've recently taken a look at the Boost.Move library and it seems that it is only possible to make 1) either non-copyable types movable or 2) make copyable types move-aware by explicitly moving them. Now, I've discovered for myself that it is possible for pre-c++09 compilers to make copyable types *implicitly* movable by detecting temporaries that can be moved. So, my question is whether this is well-known and this feature was deliberately excluded from Boost.Move or nobody has discovered it yet. It would be great to have support for copy- and (implicit) move-semantics. Klaus Triendl

5 9

[type_traits] is_less_comparable
by Frédéric Bron 10 Aug '09

10 Aug '09

Hi, One year ago, I added to the sandbox the following type_traits: - is_equal_to_comparable, - is_greater_comparable, - is_greater_equal_comparable, - is_less_comparable, - is_less_equal_comparable, - is_not_equal_to_comparable They allow to check if type T can be compared, i.e. if operator==, >, >=, <, <=, !=(T&, T&) exist. At that time, I could not build the documentation so the addition has never been reviewed. I have now a larger hard disk which allows me to have a virtual machine running linux (ubuntu). I would like to check if my documentation addition is OK, therefore could you tell me how I can compile .qbk files? Then, I would like to submit the addition for a review and future inclusion in a boost release; what is the procedure? Regards, Frédéric

2 5

[proto]: rewriting POOMA and Blitz++
by Chandrashekhar Kumar 10 Aug '09

10 Aug '09

Hello, At some time Eric expressed that all the expression template based libraries of boost (notably Phoenix, Spirit) has to be re-written using proto. I think that this target is kind of achieved by now. Can something be done along the similar lines for re-writing the top-notch libraries like POOMA and Blitz++ as a complete examples of proto applications? Does anyone has idea about how huge this undertaking can be? Thanks, Chandra

4 7

"I want everything" should build "out of the box" (on Windows)
by KTC 09 Aug '09

09 Aug '09

Users on Microsoft Windows should be able to build boost with everything, both in terms of all supported variants and all boost libraries, with a single command to bjam assuming they have all the optional supporting libraries available. An user download boost, and want to build all the libraries that require building go read the Getting Started Guide <.../getting_started/windows.html#invoke-bjam> and see the after getting bjam they use the command bjam --build-dir=build-directory toolset=toolset-name --build-type=complete stage So they enter that into the command prompt and see lots of warnings and notes about missing optional components. The warnings and notes itself is fine and informative. Actually, it's incomplete as it stand as it doesn't tell the user about Boost.IOStreams optional component requirement of bzip2 & zlib headers. Okay, the user go and install all the optional components the warnings and notes tell them. After installing Python, ICU (building it first), Expat (building it first), and MPI (say MS-MPI), they try again. This time with the command becoming bjam --toolset=... --build-dir=... --build-type=complete -sHAVE_ICU=1 -sICU_PATH="..." -sEXPAT_INCLUDE="..." -sEXPAT_LIBPATH="..." -sBZIP2_SOURCE="..." -sZLIB_SOURCE="..." stage Nope, MPI requires modification of user-config.jam or building it on its own with --with-mpi. Why? No other optional components build that way. So they look to see how they do that, and does it. Second attempt and ... nope. New to 1.39 is the errors error: link=shared together with runtime-link=static is not allowed error: such property combination is either impossible error: or too dangerious to be of any use due to the changes made as a result of <http://lists.boost.org/Archives/boost/2009/04/150675.php>. (Recently noted on <http://groups.google.com/group/boost-list/browse_thread/thread/2a7bd07468b5…>.) While catching those errors is good, maybe it should be fixed as well such that it doesn't come up in the first place if someone do a --build-type=complete with ICU. So now the users have to build Boost.Regex separately from the rest of the library (after finding how to pass the link= & runtime-link= options). By the way, at this point I would like to point out how it's strange that -sHAVE_ICU=1 mean to build with ICU, but so is -sHAVE_ICU=0 .... :S And ... nope, even separately Boost.Regex still wouldn't build without errors. No one told them they need to rename icuin.lib, icuind.lib, icuind.pdb & icudt.lib from ICU to icui18n.lib, icui18nd.lib, icui18nd.pdb & icudata.lib respectively. With Boost.Regex built, we turn to the rest of the library with --without-regex. After waiting a while, we discover ... nope, Most of the library is built but not Boost.Graph. Sorry, this time no one told them they need to change Boost.Graph's Jamfile.v2 file with "<find-shared-library>expat" to "<find-shared-library>libexpatwMT" and adding "<define>XML_STATIC". Boost is great, it's free, it's flexible and I understand it's developed for free by volunteers, but its "installation" for someone that want every libraries could be improved. :-) Regards, KTC -- Only two things are infinite, the Universe and Stupidity. And I'm not quite sure about the former. - Albert Einstein

15 56

[Interprocess::Semaphore] Deadlock on more producers - one consumer problem
by Cosimo Calabrese 09 Aug '09

09 Aug '09

Hi to all, I've a buffer of 10 positions; 4 producers put elements on the buffer and only 1 consumer pick them; the producers generate elements very fastly, but the consumer picks the element very slowly. I've decided to synchronize the producers and the consumer with a boost::interprocess semaphore initialized to 10. Before to put an element in the buffer, the producer execute a wait() in the semaphore; the 4 producers put quickly 10 elements in the buffer, so they all block on the wait(). When the consumer picks an element from the buffer, it performs a post() on the semaphore. Here is the problem: the post() unlocks only one of the 4 producers. Consider this scenario: - the producers are all in wait state; the semaphore counter is 0; - the consumer picks an element and perform a post(), that unlocked the producer_1; the semaphore counter is 1; - the producer_1 is unlocked but it doesn't produce any element; the other producers are locked; - the consumer picks the other 9 elements in the buffer and perform the 9 post() on the semaphore, but the semaphore counter becomes 2, 3, 4, ... 10, and so the semaphore doesn't signal the other producers, that remains in lock state(). --> DEADLOCK. Is there a way to unlock all the producers with the boost::interprocess::semaphore? Or I have mistaken the approach of the problem? Thanks to all, Cosimo Calabrese.

5 27

backward binary compatibility of boost shared libraries
by Андрей Пономаренко 08 Aug '09

08 Aug '09

Hello, I'm from Institute for System Programming of Russian Academy of Sciences and we are developing a free lightweight tool for checking backward/forward binary compatibility of shared C/C++ libraries in OS Linux. It checks interface signatures and data type definitions in two library versions (headers and shared objects) and searches ABI changes that may lead to incompatibility. We have released 1.2 version of this tool and we'd like you to consider its usefulness for your project. The wiki-page with the latest release of binary compatibility checker is http://ispras.linux-foundation.org/index.php/ABI_compliance_checker Andrey Ponomarenko

1 0

boost 1.40.0 release date?
by Zoran Cvetkov 08 Aug '09

08 Aug '09

I would like to know when is scheduled release date for version 1.40 of boos library? Some critical fixes are in there and I'd like to know when we should expect it? Browsing the web site didn't help me, did I missed something? Thanks in advance!

2 1

[1.40] timeline?
by John Maddock 07 Aug '09

07 Aug '09

Do we have a revised timeline for 1.40 yet? I'm asking because the regex lib is ready for a substantial update (provided trunk tests cycle OK obviously!). Thanks, John.

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[BGL] How to stopping prematurely a graph exploration
by Cosimo Calabrese 07 Aug '09

07 Aug '09

Hi to all, I'm searching for a good method to stopping prematurely a graph exploration, e.g. when I've just founded and explored a particular vertex. I think I've to create a visitor to which passing the particular vertex, but I don't know how to configure it. A very brutal method is to wrap the exploration function in a try-catch block, and then throw an exception in the examine_vertex funtion. I want to believe that there's a more elegant method than this... Best regards, Cosimo Calabrese.

4 6

[config] symbols export from shared library (#2114)
by Alexander Arhipenko 07 Aug '09

07 Aug '09

Guys, I've decided to start a new thread on this topic. The messages beyond was taken from the last ticket comments. >--------------------------------------------------------------------- >*** Changed 19 hours ago by johnmaddock *** >--------------------------------------------------------------------- > >Is this nearly ready to go in Trunk now? > >Before it does at the very least we need: > >1) An update for http://www.boost.org/development/separate_compilation.html >2) An update for the Boost.Config docs for each of these new macros. >3) A clear understanding of what BOOST_SYMBOL_FORWARD_EXPORT/IMPORT do. >4) A clear understanding of what needs re-exporting - >IMO BOOST_EXCEPTION_EXPORT is somewhat misleading since as I understand the gcc docs >this may need to be applied to any class that has "vague linkage" whatever that is. >Also do we need to re-export std lib exceptions from our SO's? >Do we have a dependency analysis to know when we need to use these (or that we don't need to)? > >John. > >----------------------------------------------------------------- >*** Changed 3 hours ago by arhipjan@… *** >----------------------------------------------------------------- > >Replying to johnmaddock: > >JFYI, stdcxx library (at least of version 4.1.1 and later) >already have default visibility for std::exception, std::bad_exception, i.e: > >//exception header > >#pragma GCC visibility push(default) > >namespace std { > > class exception {/*...*/}; > class bad_exception {/*...*/}; > >//... > >Also logic_error, runtime_error don't cause abnormal program termination >since they have key functions >(i.e. at least one non-inline virtual function). >--------------------------------------------------------------------- >*** Changed 26 minutes ago by anonymous *** >--------------------------------------------------------------------- > >I forgot one other requirement: we should maybe try and put together a small test case to check that this all works. > >Good to hear that libstdc++ already does the necessary work, does this mean that exceptions that inherit from std::runtime_error (as I think all Boost >exceptions do?) are automatically visable and don't need re-exporting on account of their virtual functions? > >Oops, one other thing (sorry!), how if at all is Boost.Exception effected by this - especially as it's header only? > >Cheers, John. I would like to make some comments: 1) BOOST_EXCEPTION_EXPORT macro In current patch version there is no need for this macro, since all the symbols marked with BOOST_SYMBOL_EXPORT always have default visibility on gcc. (In the original version, they have default visibility when building shared library and hidden visibility when using it in another shared library). 2) >>>>Also do we need to re-export std lib exceptions from our SO's? >>JFYI, stdcxx library (at least of version 4.1.1 and later) >>already have default visibility for std::exception, std::bad_exception >>[snip] >>Also logic_error, runtime_error don't cause abnormal program termination >>since they have key functions >>(i.e. at least one non-inline virtual function). >Good to hear that libstdc++ already does the necessary work, >does this mean that exceptions that inherit from std::runtime_error (as I think all Boost exceptions do?) >are automatically visable and don't need re-exporting on account of their virtual functions? The exceptions that inherit std::exception (or std::runtime_error) are not visible. But throwing such exception from shared library and catching it in another exe or lib doesn't cause abnormal termination (but only if thrown exception have at least one key function)

1 0

Re: [boost] Using channel with boost 1.39.0
by Yigong Liu 07 Aug '09

07 Aug '09

Hello Joaquim, Thanks for your help. I'll soon fix these issues with a new update to vault. Best Regards. Yigong > > However in some samples has appeared warnning about deprecated casts > to transfrom from std::string to char*. I attach to this e-mail the > output of compilation of samples to fix the warnings. > > Thanks and Best Regards, > Joaquim Duran > >

1 0

Boost.Plot? - Scalable Vector Graphics
by Paul A. Bristow 07 Aug '09

07 Aug '09

Jake Voytko started this library during a 2007 GSoC and I have now expanded it quite a bit, and begun to use it for my own purposes (including preparing the plot for the Boost.Math library functions and statistical distributions). Before I do any more work on it, I'd appreciate feedback from Boosters on how useful they think it might be, perhaps as a Boost library? Although it still has plenty of wrinklies (the calculation of positioning of titles, legends, axes labels and ticks labels is intricate - to say the least). And there are not-a-few nasty warts (this may be the 1st version to throw away?), so it is in no way review-ready. But I believe it is working well enough for you to try to use it - and to give me feedback. There are of course hundreds of programs for plotting. What is special about *this* library is that it is in C++ and it has a Boost license. It allows you to add just a few lines of code to the end of your C++ program to take data from any STL container (all or part) and produce a plot as a Scale Vector Graph (.svg) file. (No need to export data to a file and suck into Excel ;-) Applause!) .svg files can be displayed by all good Internet Browsers (and even by IE8 with an Adobe add-in). They are very small but high quality, highly zip compressible, and equally suitable for printing to viewing on mobiles (only the features of Tiny SVG are used.). It takes as little code as svg_2d_plot my_plot; my_plot .plot(map1, "Series 1").stroke_color(blue) .plot(map2, "Series 2").stroke_color(red") .autoscale(map1); my_plot.write("./2d_simple.svg"); but you can have hours of fun trying out hundreds of options to produce some rather fancy plots. For your amusement, attached are a few (mostly contrived) examples (with tasteless garish colors just to highlight the possible options). There are also lots and lots of other examples. (Note that the 20 plots occupy a mere 30 kb when zipped). Unusually, there is lots (too much? - 6Mbyte hyperlinked and indexed PDF!) of documentation, produced using the C++ in QuickBook with Doxygen reference info and John Maddock's auto-indexing. But there are hundreds of options, so you will need all the help you can get from tutorials, examples and indexes. A novel feature is the built-in handling of an 'uncertain' type (based on Evan Marshal Manning, C/C++ Users Journal, March 1996 page 29 to 38) including a double 'most likely' value, an 'uncertainty' estimate, roughly standard deviation, and an estimate of 'degrees of freedom'. This can be used to display confidence ellipses and label values "1.23 +-0.01 (21)", for example. (Of course, you can make much better confidence estimates using the Boost.Math library). You can view and can get code from the Boost sandbox https://svn.boost.org/svn/boost/sandbox/SOC/2007/visualization Docs are available to build as html and pre-built as pdf (patience - 6 Mbyte!) https://svn.boost.org/svn/boost/sandbox/SOC/2007/visualization/libs/svg_plot /doc/pdf/svg_plot.pdf or http://tinyurl.com/coqlbg (or ask if you want zips instead). Paul PS Thanks to all those who have offered support, especially John Maddock of course. It has stress-tested the Quickbook - Doxygen indexing system ;-) I haven't managed to make the index work perfectly yet and I'm sure it can be improved. PPS If I were doing this again, I would not use 'derived' trick to permit re-use of functions by 1D, 2D and boxplots - it causes the Intellisense of MS VisualStudio IDE 'Intelligence Circuits' to melt (and sometimes crash - workaround - delete the .ncb file) making the nice 'goto definition' feature ineffective and makes debugging difficult (as does the use of set and get functions). I suspect it makes compile times longer too. There must be a better way - suggestions welcome. But I *would* use the chaining feature - I think it makes a very nice syntax for the user - but tell me what you think. --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

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[Boost.Thread][Boost1.39]:boost::thread& is not accessible from boost::move
by Karun Gahlawat 07 Aug '09

07 Aug '09

Running CC 5.10 to build Boost.Thread using the following command: Referred to this list by boost-build Trying to build Boost.Thread using Sun CC 5.10 on opensolaris. This one looks like a generic error. "CC" +d -library=stlport4 -g -mt -m64 -KPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_THREAD_BUILD_DLL=1 -DBOOST_THREAD_POSIX -I"." -c -o "/tmp/boost/boost/bin.v2/libs/thread/build/sun/debug/a ddress-model-64/stdlib-sun-stlport/threading-multi/pthread/thread.o" "libs/thread/src/pthread/thread.cpp" Getting this error: "./boost/thread/detail/thread.hpp", line 344: Error: boost::thread::thread(boost::thread&) is not accessible from boost::move(boost::detail::thread_move_t<boost::thread>). 1 Error(s) detected. -- Karun -

2 2

[function_types] documentation issues
by Sam Partington 06 Aug '09

06 Aug '09

Hi all, I am writing a library that aims to make using dynamic libraries easier across platforms. The aim is the following : dynamic::library lib("sharedlib.so"); dynamic::function<int (int, int> fn(lib, "fn"); int result = fn(1, 2); So to achieve this I needed to implement forwarding functions and I used function_types to make this easier. This all worked fairly well, but in general I really struggled with figuring out how to use function_types. Though simple uses were fairly straight forward, as soon as I came across a STDCALL function it all fell over and I got compiler errors "'value' : is not a member of 'boost::function_types::function_arity<T>". I have managed to fix it, but the route there was far from obvious, and I would put that entirely down to incomplete and misleading documentation. Eventually, I found the Reference->Macros section which discussed calling conventions : BOOST_FT_CC_* Enables a specific calling convention. * dentoes the macro suffix, as defined by BOOST_FT_CC_NAMES or BOOST_FT_BUILTIN_CC_NAMES. The macro expands to a list of restrictions, separated by the | character. Possible items are: callable_builtin member non_member variadic non_variadic If no such macro is defined for a particular calling convention, it is disabled. Example: #define BOOST_FT_CC_STDCALL non_variadic|callable_builtin // enables stdcall calling convention for all non-variadic, // callable, builtin types Ahah! It looked like I needed to #define BOOST_FT_CC_STDCALL non_variadic|callable_builtin, as per the example there. However this caused monstrous compile errors from the guts of function_types initially stating that "'...' requires cdecl". Further reading pointed me to this : BOOST_FT_COMMON_X86_CCs Defining this macro causes the following macros to be defined, if not defined already: #define BOOST_FT_CC_CDECL BOOST_FT_COMMON_X86_CCs #define BOOST_FT_CC_STDCALL non_variadic|BOOST_FT_COMMON_X86_CCs #define BOOST_FT_CC_FASTCALL non_variadic|BOOST_FT_COMMON_X86_CCs So I added the following : #define BOOST_FT_COMMON_X86_CCs But this also failed with more bizarre errors, eventually I experimented with : #define BOOST_FT_COMMON_X86_CCs 1 Which finally worked. But the docs do not indicate that you need to define it with any particular value. The whole problem would have been so much simpler if there was one of more of the following sections in the documentation : "Getting Started", "Calling Conventions", "Common Pitfalls", or an FAQ. Sam

1 0

[program_options] Can this library write config file?
by Guanqiang Liu 06 Aug '09

06 Aug '09

the boost::program_options can read options from config file. But, can this library write opions into config file?

3 2

[BGL] To customize the graph traversing
by Cosimo Calabrese 06 Aug '09

06 Aug '09

Hi to all, I'm studying the BGL, and I've a question. I've noticed that: - the traversing algorithms, like breadth first search, only decide how to traverse the graph, but do not perform specific calculations; - if I want to perform any calculation during the traverse, I can do it passing a custom visitor to the algorithm. But the question is: how can I customize the traverse method? The algorithms always explore enterely the graph. EXAMPLE: every edge (u, v) of a graph have a property "edge_can_traverse_t" that says on which of adjacent edges starting from v I can continue the traverse. _C _F o| /| o / o / A---->B---->D o o o >G \ \ \ \ _\| _\| E H ----------------------------------------- | edge | property edge_can_traverse_t | | | (vector<edge>) | ----------------------------------------- | (A,B) | (B,D) , (B,E) | | (B,C) | empty | | (B,D) | (D,F) , (D,H) | | (B,E) | empty | | (D,F) | empty | | (D,G) | empty | | (D,H) | empty | ----------------------------------------- For example, if I come from the (A,B) edge, I want that the algorithm consider only the (B,D) and (B,E) edge, and skip the (B,C) edge. The solution I found is to modify the breadth_first_search algorithm, adding a predicate to the visitor and performing a control when the algorithm examines the outer edges of the current vertex. Something like this: //============================================================================== // PREDICATE (in the visitor) //============================================================================== template <class IncidenceGraph, class PredecessorMap> bool can_traverse_edge( edge_descriptor e, IncidenceGraph &g, PredecessorMap p ) { typedef graph_traits<IncidenceGraph>::vertex_descriptor VertexDescriptor; VertexDescriptor u = source( e, g ); // select the source of the edge EdgeDescriptor eFrom = edge( p(u), u ); // select the previous visited edge if ( e is contained in the edge_can_traverse_t property of eFrom ) return true; else return false; } //------------------------------------------------------------------------------ //============================================================================== // breadth_first_visit //============================================================================== template <class IncidenceGraph, class Buffer, class BFSVisitor, class ColorMap> void customized_breadth_first_visit (const IncidenceGraph& g, typename graph_traits<IncidenceGraph>::vertex_descriptor s, Buffer& Q, BFSVisitor vis, ColorMap color) { [.....] put(color, s, Color::gray()); vis.discover_vertex(s, g); Q.push(s); while (! Q.empty()) { Vertex u = Q.top(); Q.pop(); vis.examine_vertex(u, g); for (tie(ei, ei_end) = out_edges(u, g); ei != ei_end; ++ei) { if ( !vis.can_traverse_edge( *ei ) ) continue; [.....] } //------------------------------------------------------------------------------ Does it exist a better mechanism to control the traverse with the BGL? Or I must implement my solution? Best Regards, Cosimo Calabrese.

3 13