September 2007 - Boost-users

mt safe containers - newbie [C1]
by graham.walsh＠sgcib.com 17 Sep '07

17 Sep '07

Hi, we're in the process of optimising our application. We've already deployed serialization, memory pools and now we're looking at the container code. unfortunately it is highly inefficient. We're attacking some basic optimisations we can use (setting the capacity etc), but there's one thing I'd like to clarify. Right now we're running with STL containers, vector and map for the most part. Before modifying the container in question, we're obliged to lock/protect the container as we have a highly concurrent environment. I would like to know if there's a MT safe container available...i.e. for map and vector. If yes, could anybody please direct me to a doc page that discusses it. I apologise if its staring me in the face but I can't get any doc that discusses mt safety. thanks much for any info and have a nice day Graham ************************************************************************* This message and any attachments (the "message") are confidential and intended solely for the addressee(s). Any unauthorised use or dissemination is prohibited. E-mails are susceptible to alteration. Neither SOCIETE GENERALE nor any of its subsidiaries or affiliates shall be liable for the message if altered, changed or falsified. ************ Ce message et toutes les pieces jointes (ci-apres le "message") sont confidentiels et etablis a l'intention exclusive de ses destinataires. Toute utilisation ou diffusion non autorisee est interdite. Tout message electronique est susceptible d'alteration. La SOCIETE GENERALE et ses filiales declinent toute responsabilite au titre de ce message s'il a ete altere, deforme ou falsifie. *************************************************************************

2 1

serialization mystery
by Neal Becker 17 Sep '07

17 Sep '07

I'm stumped as to why my template typedef simulation doesn't work with serialization. Here's a simple example: template<typename T> struct A { }; template<typename T> struct B { typedef A<T> type; }; namespace boost { namespace serialization { template<class Archive, class T> inline void serialize (Archive &ar, typename B<T>::type & v, const unsigned int file_version) { <<< This won't work //inline void serialize (Archive &ar, A<T> & v, const unsigned int file_version) { <<< This is OK boost::serialization::split_free (ar, v, file_version); } } } I expected typename B<T>::type is equivalent to A<T>, but gcc-4.1.2 doesn't agree. The latter compiles, but the 1st gives: /usr/local/src/boost.hg/boost/serialization/access.hpp:109: error: ‘struct A<int>’ has no member named ‘serialize’

2 1

iostreams + unzip
by Surya Kiran Gullapalli 17 Sep '07

17 Sep '07

Hello all, I'm newbie to boost::iostreams library. I'm trying to unzip a .zip file. for that I'm using iostream's zlib_decompressor class to inflate it. I'm using the sample code provided in the documentation. What I was getting is an exception (zlib error). My question is can i use boost::iostreams classes for unzipping a .zip file.? If so how? a small sample snippet would be helpful. Thanks in advance, Surya

3 2

[filesystem] expand user
by Tim Blechmann 16 Sep '07

16 Sep '07

hi all, is there a boost::filesystem equivalent of python's os.path.expanduser? something that returns "/home/tim/myfancypath" from the path "~/myfancypath"? thanks in advance, tim -- tim(a)klingt.org ICQ: 96771783 http://tim.klingt.org Silence is only frightening to people who are compulsively verbalizing. William S. Burroughs

1 0

Review wizard's report for October 2007
by Ronald Garcia 15 Sep '07

15 Sep '07

============================================ Review Wizard Status Report for October 2007 ============================================ News ==== August 17, 2007 -- Time Series Accepted. Announcement: http://lists.boost.org/boost-announce/2007/08/0142.php July 24, 2007 -- Boost Version 1.34.1 Released. This is a bug fix release addressing many problems with the 1.34.0 release. Announcement: http://svn.boost.org/trac/boost/query? status=closed&milestone=Boost+1.34.1 We need experienced review managers. 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 cs dot indiana dot edu" and "jphillip at capital dot edu" respectively. 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 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 ============ * Exception * Finite State Machines * Floating Point Utilities * Switch * Property Map (fast-track) * Graph (fast-track) -------------------- Exception --------- :Author: Emil Dotchevski :Review Manager: Need Volunteer :Download: http://www.revergestudios.com/boost-exception/boost-exception.zip :Description: The purpose of this library is to free designers of exception classes from having to consider what data needs to be stored in exception objects in order for the catch site to be able to make sense of what went wrong. When the exception class is used, arbitrary values can be stored in any exception. This can be done directly in the throw-expression, or at a later time as the exception object propagates up the call stack. The ability to add data to any exception object after it has been thrown is important, because often some of the information needed to handle an exception is unavailable at the time of the throw. Finite State Machines --------------------- :Author: Andrey Semashev :Review Manager: Martin Vuille :Download: `Boost Sandbox Vault <http://tinyurl.com/yjozfn>`__ :Description: The Boost.FSM library is an implementation of FSM (stands for Finite State Machine) programming concept. The main goals of the library are: * Simplicity. It should be very simple to create state machines using this library. * Performance. The state machine infrastructure should not be very time and memory-consuming in order to be applicable in more use cases. * Extensibility. A developer may want to add more states to an existing state machine. A developer should also be able to specify additional transitions and events for the machine with minimum modifications to the existing code. Floating Point Utilities ------------------------ :Author: Johan Råde :Review Manager: Need Volunteer :Download: `Boost Sandbox Vault <http://boost-consulting.com/vault/ index.php?directory=Math%20-%20Numerics>`__ :Description: The Floating Point Utilities library contains the following: * Floating point number classification functions: fpclassify, isfinite, isinf, isnan, isnormal (Follows TR1) * Sign bit functions: signbit, copysign, changesign (Follows TR1) * Facets that format and parse infinity and NaN according to the C99 standard. (These can be used for portable handling of infinity and NaN in text streams.) Switch ------ :Author: Steven Watanabe :Review Manager: Need Volunteer :Download: `Boost Sandbox Vault <http://boost-consulting.com/vault/ index.php? action=downloadfile&filename=mcs_units_v0.7.1.zip&directory=Units>`__ :Description: The built in C/C++ switch statement is very efficient. Unfortunately, unlike a chained if/else construct there is no easy way to use it when the number of cases depends on a template parameter. The Switch library addresses this issue. Property Map (fast-track) ------------------------- :Author: Andrew Sutton :Review Manager: Jeremy Siek :Download: http://svn.boost.org/svn/boost/sandbox/graph-v2 :Description: A number of additions and modifications to the Property Map Library, including: * A constant-valued property map, useful for naturally unweighted graphs. * A noop-writing property map, useful when you have to provide an argument, but just don't care about the output. * See `ChangeLog <http://svn.boost.org/trac/boost/browser/sandbox/graph- v2/libs/property_map/ChangeLog>`__ for details. Graph (fast-track) ------------------ :Author: Andrew Sutton :Review Manager: Jeremy Siek :Download: http://svn.boost.org/svn/boost/sandbox/graph-v2 :Description: A number of additions and modifications to the Graph Library, including: * Two new graph classes (undirected and directed) which are intended to make the library more approachable for new developers * A suite of graph measures including degree and closeness centrality, mean geodesic distance, eccentricity, and clustering coefficients. * An algorithm for visiting all cycles in a directed graph (Tiernan's from 1970ish). It works for undirected graphs too, but reports cycles twice (one for each direction). * An algorithm for visiting all the cliques a graph (Bron&Kerbosch). Works for both directed and undirected. * Derived graph measures radius and diameter (from eccentricity) and girth and circumference (from Tiernan), and clique number (from Bron&Kerbosch). * An exterior_property class that helps hides some of the weirdness with exterior properties. * runtime and compile-time tests for the new algorithms. * a substantial amount of documentation * Graph cores, implemented by David Gleich (@Stanford University) * Deterministic graph generators - capable of creating or inducing specific types of graphs over a vertex set (e.g., star graph, wheel graph, prism graph, etc). There are several other specific types that could be added to this, but I haven't had the time just yet. Libraries under development =========================== Please let us know of any libraries you are currently developing that you intend to submit for review.

2 1

a little help with trimming strings
by Mark Wyszomierski 15 Sep '07

15 Sep '07

Hi, Is it possible using the trim() family of functions to remove not just white space, but some substring from the right of a string? For example, if I want to remove commas from the right: string str = "whatever,"; TrimRight(str, ","); // str == "whatever" now. or a full string to trim: string str = "hello world"; TrimRight(str, "world"); // str == "hello "; I could write these simple functions myself but am wondering if boost can do that already, Thanks, Mark

3 3

boost::interprocess
by Kamil Shakirov 14 Sep '07

14 Sep '07

Hi. I'd like to evaluate boost::interprocess (the latest snapshot from CVS) but cannot find documentation. I also have tried to generate docs using boost::quickbook but it doesn't work and seems to be broken. Where could I get the latest docs for boost::interprocess? Thanks.

3 3

[thread] Including boost/thread/mutex.hpp breaks .NET applications
by Boris 14 Sep '07

14 Sep '07

Is the following problem already known? 1) Create a new C++/CLI project in Visual Studio 2005 (eg. a console application). 2) Include the header <boost/thread/mutex.hpp>. That's all. When you build and run the application you see the following Windows error message: "The application failed to initialize properly (0xc000007b). Click on OK to terminate the application." If you build a .NET DLL and try to use it from another .NET application the error message changes to: "is not a valid Win32 application. (Exception from HRESULT: 0x800700C1)" In both cases Windows refuses to load the file. While you normally don't need Boost.Thread in a .NET application I ran into this problem because we have a thin .NET layer on top of a native C++ code DLL. As the DLL makes heavy use of various Boost libraries the header <boost/thread/mutex.hpp> ends up in the .NET DLL. Does anyone have an idea why including this header is a problem? Boris

2 2

vector proxy assignment in boost ublas
by e r 14 Sep '07

14 Sep '07

hi, i'm trying to understand the different forms of assignments in boost ublas (a) and b)). some help would be appreciated. // Assignment a) BOOST_UBLAS_INLINE vector_range &operator = (const vector_range &vr) { vector_assign<scalar_assign> (*this, typename vector_temporary_traits<V>::type (vr)); return *this; } b) BOOST_UBLAS_INLINE vector_range &assign_temporary (vector_range &vr) { // assign elements, proxied container remains the same vector_assign<scalar_assign> (*this, vr); return *this; }

1 0

BGL connected_components ComponentMap
by Andreas Fabri 13 Sep '07

13 Sep '07

Hello, Why does the ComponentMap not get accessed via the property map obtained with get(vertex_index, g) ? Many other algorithms do that, e.g. dijksta_shortest_paths. Is this just an inconsistency, or are there technical reasons. In the first case, is there a chance that this gets fixed or would it break backward compatibility. andreas

2 2