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Changing case with regex_format
by Keith MacDonald 06 Mar '04

06 Mar '04

The following useful Perl expressions seem to have been omitted from regex_format: \l lowercase next char \u uppercase next char \L lowercase till \E \U uppercase till \E \E end case modification Was there a good reason for that? The only way I can see to implement those expressions is to take a copy of regex_format.hpp, then hack _reg_format_aux. I think that it would also be necessary to change the undocumented regex_traits class, to do upper case conversion, as it only seems to do lower casing at present. Is there an easier way? Thanks, Keith MacDonald

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install? and simple thread program.
by Duong, Sanh N. 06 Mar '04

06 Mar '04

All, Does anyone have an example of how to install boost and bjam? Does someone also have a simple program using boost and threads. Thanks in advance, Sanh

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Futures revisited
by Slawomir Lisznianski 05 Mar '04

05 Mar '04

Hello, During discussions on possible extensions to Boost.Threads, concept of Futures came up rather frequently. Below, I’d like to introduce a particular implementation available at www.rhapsodia.org of which requirements were defined as follows: 1. Provide means to register exception types with a "Future Registry". Rationale: I find it imperative that users should not have to define a list of exception types on each invocation yielding a Future object. Instead, provide the ability to register exception types with a Future Registry and bundle it with Future objects. I feel that compile time registration should be sufficient. 2. Work under the assumption that asynchronous invocations returning Futures and system threads are not coupled. In particular, Futures implementation should not relay on joining with a particular thread to perform synchronization for returning results. Rationale: Although most prevalent, the technique of joining with a particular thread to synchronize on returning result is too limiting. It implies that each task be run on a dedicated thread, specially created to handle it and destroyed to meet with a caller using a Future. Although this approach may be adequate under certain conditions, it generally tends to be expensive on system resources and disorganizes the application. For example, it’s impossible to control the number of concurrently running threads. It may also perform poorly if executed code happens to run shortly as the overhead of creating a thread and cleaning up after it may be significant. More robust approach is to use a queue and a thread pool for running tasks. This adds complexity on the synchronization side, as we can no longer rely on a lifetime of a thread to join with Future’s result. 3. Ability to utilize Futures with arbitrary code without explicit support for them. Rationale: For implementation to be widely adopted, it should be possible to turn just about any function call into a Future-armored asynchronous invocation. No explicit thread synchronization primitives should be used as well. 4. Implement using existing Boost.Threads facilities only. Rationale: Boost.Threads library provides enough support to implement Futures paradigm that meets requirements listed here. 5. STL and Boost compatible. For example, storing Futures in an STL container. Be strongly typed. Futures implementation and usage patterns must naturally coexist with STL and Boost code. Additionally, compile-time type validation is key to safer code. Attached is a sample file from Rhapsodia library showing the use of Futures. Regareds, Slawomir Lisznianski [ www.rhapsodia.org ]

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Constructor in for adjacency_matrix missing?
by Heiko Bauke 05 Mar '04

05 Mar '04

Hello, since some weeks I'm using the BGL. It's really a great library. But I'm a bit confused about the documentation for the template class adjacency_matrix. According to the BGL-book and also the online documentation there should be three constructors for adjacency_matrix: adjacency_matrix(vertices_size_type n, const GraphProperty& p = GraphProperty()) template <typename EdgeIterator> adjacency_matrix(EdgeIterator first, EdgeIterator last, vertices_size_type n, const GraphProperty& p = GraphProperty()) and template <typename EdgeIterator, typename EdgePropertyIterator> adjacency_matrix(EdgeIterator first, EdgeIterator last, EdgePropertyIterator ep_iter, vertices_size_type n, const GraphProperty& p = GraphProperty()) but actually in boost/graph/adjacency_matrix.hpp is only the constructor adjacency_matrix(vertices_size_type n_vertices) is defined. So it's not possible to construct an adjacency_matrix from a pair of iterators (as it is possible for adjacency_list). Has this constructor been removed or never been implemented? Such a constructor would be very useful for me. Another point that confuses me is that the template parameter GraphProperty for template <typename Directed = directedS, typename VertexProperty = no_property, typename EdgeProperty = no_property, typename GraphProperty = no_property, typename Allocator = std::allocator<bool> > class adjacency_matrix; seams never been used for the implementation of this class. regards, Heiko P.S. I'm using boost 1.30.0. -- -- Gute Sitten haben für die Gesellschaft mehr Wert als alle -- Berechnungen Newtons. (Friedrich II., der Große, 1712-1786) -- Supercomputing in Magdeburg @ http://tina.nat.uni-magdeburg.de -- Heiko Bauke @ http://www.uni-magdeburg.de/bauke

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RE: [Boost-users] Hash Table
by Neil Mackie 05 Mar '04

05 Mar '04

jeff suggested, >>You could also look at the STLPort hast table. I too recently wanted to use a hash table and found that neither VC++ 6 not Boost have one. I investigated STLPort thinking that I could just use a one or two .h files to get a hast table template. I carried out a number if iterations involving installing more and more STLPort files to the point that I might as well have installed the whole thing, something I did not want to do as I already have STL as provided by VC++, and Boost of which I'm using only a very small part. The outcome was that I chose another collection type rather than have two STL implementations installed (who knows what type of problems that would have caused). I understand that VC++ 7 does have a hash table implementation. You have to be very careful looking at the documentation at the Microsoft web site as they appear not to distinguish between documentation for V7 and V6. Regards, Neil J Mackie *********************************************************************************** Ofcom is the regulator for the UK communications industry, with responsibilities across television, radio, telecommunications and wireless communications services. Ofcom exists to further the interests of citizen-consumers as the communications industries enter the digital age. Ofcom has taken over the responsibilities and assumed the powers of the five former regulators it has replaced - the Broadcasting Standards Commission, the Independent Television Commission, Oftel, the Radio Authority and the Radiocommunications Agency. This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the originator of the message. This footer also confirms that this email message has been scanned for the presence of computer viruses. Any views expressed in this message are those of the individual sender, except where the sender specifies and with authority, states them to be the views of Ofcom. ***********************************************************************************

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RE: [Boost-users] Hash Table
by Ben Hutchings 04 Mar '04

04 Mar '04

Muhammad Hussain <m <mailto:mhussain@i.kyushu-u.ac.jp> <mailto:mhussain@i.kyushu-u.ac.jp> <mailto:mhussain@i.kyushu-u.ac.jp> hussain(a)i.kyushu-u.ac.jp> wrote: Is there any library in boost that provides hash table and the methods to manipulate it? No, but there are common extensions to the standard containers library (aka STL) that are included with many compilers, called hash_map and hash_set. Unfortunately there are several implementations of these which do not have quite the same interface. Ben.

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Where is the jam_src Makefile?
by Dr Mark H Phillips 04 Mar '04

04 Mar '04

Hi, I am trying to compile a bjam executable from scratch (under Linux). In the file: boost_1_31_0/tools/build/jam_src/README it says: The Makefile (UNIX, NT), build.com (VMS), Build.mpw (Mac MPW) are for bootstrapping. Once jam is built, it can rebuild itself. But I can't find the Makefile anywhere! It is not in that directory, and I can't find it anywhere else? Am I blind, or is it missing? Thanks, Mark.

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Hash Table
by Muhammad Hussain ???? ???? 04 Mar '04

04 Mar '04

Is there any library in boost that provides hash table and the methods to manipulate it? Thanks a lot in advance. Hussain

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filesystem lib and dangling symbolic links
by Andre Hentz 04 Mar '04

04 Mar '04

According to http://www.boost.org/libs/filesystem/doc/operations.htm#remove remove() is supposed to remove symbolic links. However, the source code says: if exists(ph) remove; Shouldn't it be: exists(ph) || symbolic_link_exists(ph) Best, Andre Hentz

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Boost (& Visual Studio 2003) for Dummies?
by Matthew Jankowski 03 Mar '04

03 Mar '04

Hey all, My need is to combine a program I've written with some linear algebra. I can generally do most basic tasks in C/C++, but not yet derived classes and the like. Anyway, not wanting to reinvent the wheel, my searches revealed that 'boost' might be a good source of code for some math functions I will need, essentially matrix operations. I read the getting started page http://boost.org/more/getting_started.html, all I managed to do was run the batch file in the tools/build folder, but I don't think this installed any libraries, or if it did, it didn't put them where I need them..I don't have much experience working from the command line in Windows. Boost looks good, can anyone help me get started? Thanks, Matt

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