October 2004 - Boost - lists.preview.boost.org

[serialize] xml archives and base 64 encoded binary data
by Russell Hind 25 Oct '04

25 Oct '04

Hi, I'm writing some binary data to an xml_oarchive (a vector of floats). I'm then giving the xml files to some python uses we have here so they can read them in. They had trouble with the base64 encoding of the binary data. One has mentioned that base64 spec says an '=' must be appended to the data to indicate the padding up to the next 4-byte multiple. When they added an '=' to the data between the tags in the resultant xml file, they could decode it successfully. If it is in the spec (am trying to find a link to check this), can the the base64 encoding in serialize be modified to do this before the 1.32.0 release, so it conforms to the standard? Thanks Russell

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[patch] [filesystem] Get rid of a 'uninitialized' warning
by larsbj＠gullik.net 25 Oct '04

25 Oct '04

This patch make a warning on gcc about uninitialized variable go away. Please apply to branch and main trunk. -- Lgb

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RE: [boost] Re: Library Proposal: database (boost::db)
by Brian Braatz 25 Oct '04

25 Oct '04

"> On Behalf Of Jeff Garland > Sent: Sunday, October 17, 2004 8:17 AM > To: boost(a)lists.boost.org > Subject: Re: [boost] Re: Library Proposal: database (boost::db) > > On Sat, 16 Oct 2004 23:35:37 +0000 (UTC), Steve Hutton wrote > > On 2004-10-15, Maciej Sobczak <prog(a)msobczak.com> wrote: > > > > > > http://www.msobczak.com/prog/soci/ > > > > > > This library aims at simple usage patterns, where intuitive and almost > > > "embedded" syntax at at premium. A very different approach from those > > > you discuss, but in fact complementary and can be merged with other > > > approaches. > > > > As someone who has used odbc, jdbc, dbtools, sqlapi, otl, occi, etc., > > this looks very nice to me. Further, the relative simplicity > > suggests it would be straightforward to implement for the leading > databases. > Jeff Garland Writes: > I've added a page to the Wiki to record this discussion -- feel free to > add > your thoughts on the basic requirements there... > " Thank you Jeff for setting that up. I just added " 5) Does not require the usage of RTTI 6) Allows for the user of the library to "plug in" thier own binding \ subscription system. (to support bound controls) "

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[thread] Undefined behaviour of mutex?
by Roland Schwarz 25 Oct '04

25 Oct '04

While making use of mutex objects, namely in the wait function I found out that I may not destroy a mutex while a thread is waiting for it to become signalled. On windows this results in undefined behaviour and with pthreads this raises an assertion (in debug build). I am aware that this could be solved by using an additional "aborted" variable that could be tested in the while loop of the cond.wait(lk) call, but I cannot see a straightforward way how to test abortion when waiting in a try to simply lock such a mutex. So I raise the question if it would be desirable to have the mutex "throw exceptions to all threads" that are waiting for it when it is to be destroyed? Does anyone have another idea of how to deal with this situation properly? regards, Roland

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RE: [boost] Re: Library Proposal: database (boost::db)
by Brian Braatz 25 Oct '04

25 Oct '04

> -----Original Message----- > From: boost-bounces(a)lists.boost.org [mailto:boost-bounces@lists.boost.org] > On Behalf Of David B. Held > Sent: Friday, October 22, 2004 7:08 PM > To: boost(a)lists.boost.org > Subject: [boost] Re: Library Proposal: database (boost::db) > > Jeff Garland wrote: > > On Fri, 22 Oct 2004 15:07:46 -0600, Brian Braatz wrote > > [...] > >>6) Allows for the user of the library to "plug in" thier own binding > >>\ subscription system. (to support bound controls) " > > > > Can you clarify what you mean by 'bound controls'? > > I assume he means a visual control that automagically reflects an > underlying dataset (and updates it when the control gets updated). > > Dave [Brian Braatz] I just need (for work I am doing) an abilty to PLUG something that gets called when the data is changed. This functionality supports making a OS Specific binding mechanism for UI controls. (yes there is another way to do it- I tend to prefer the "bind it once and then forget it" metaphor)

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RE: [boost] Re: Library Proposal: database (boost::db)
by Brian Braatz 25 Oct '04

25 Oct '04

> -----Original Message----- > On Behalf Of Jeff Garland > Sent: Friday, October 22, 2004 3:35 PM > Subject: RE: [boost] Re: Library Proposal: database (boost::db) > > On Fri, 22 Oct 2004 15:07:46 -0600, Brian Braatz wrote > > > Thank you Jeff for setting that up. > > > > I just added > > I moved your thoughts to the main page of discussion -- somehow you wound > up > on a closely related, but not the same name page... > > http://www.crystalclearsoftware.com/cgi- > bin/boost_wiki/wiki.pl?Relational_Database_Access [Brian Braatz] Thank You > > > 5) Does not require the usage of RTTI > > Why? This seems like an arbitrary restriction to me. Further, for some > dynamic > query capabilities it seems like it would be a good way to implement the > needed fuctionality. Of course for simple static SQL it wouldn't be > needed. > [Brian Braatz] 2 points- * I blelieve RTTI is a step of last resort (I would be an agreement with Bjarne in the D&E with this principle) * It is possible to make a Boost.Table without having to use RTTI- in fact you can do a better design with out it. I.e. Allowing for the USER of boost.table to plug in their own types (this is important) > > 6) Allows for the user of the library to "plug in" thier own binding > > \ subscription system. (to support bound controls) " > > Can you clarify what you mean by 'bound controls'? > > Jeff [Brian Braatz] Control binding is one example. And PLEASE understand I am only talking about a boost.table in the CONTEXT of a database framework. (please read the doc referenced earlier). What I am basically saying is that a table needs to support a mixin or something similar to support this usage pattern. To specifically answer your question, this would simply allow the user of the table to "plug in" their own notification system for when data changed. If this functionality were supported, then the user of the class would be able to hook into that allowing for a "update" to an OS specific GUI control. This mechanism however, from a boost perspective, only would need to be allowable in the MODEL of the code created.

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[serialize] xml archives and versioning
by Russell Hind 25 Oct '04

25 Oct '04

The header of our xml archive looks like this: <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="3"> <CoatingScanConfig class_id="0" tracking_level="0"> The object written as CoatingScanConfig didn't have a class version specified (and therefore there isn't one in the header). When writting this class, the version parameter is passed in to the serialize() method is 0 for the class, but when reading it, the version number is subsequently passed in as 3 (which looks like the archive version). Should it not be 0 also? Is 0 a valid version number for a class? If I specify the class version as 1, then reading and writing both get '1' as the version, but if I don't specify a version, or I specify 0, then writing gets 0, but reading gets '3'. If 0 isn't valid, then could there be a static_assert catching this? And a quick usage question: If a class isn't versioned, is an inherent 'version 0' written to the archive so that a version number of 1 can be applied to the object later when it is modified, or do objects need to be given a version number from the start? Thanks Russell

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[Test] Linking problems
by David B. Held 25 Oct '04

25 Oct '04

unit_test_log.o: In function `boost::unit_test::unit_test_log::unit_test_log()': unit_test_log.o(.text+0x17e): undefined reference to `boost::unit_test::ut_detai l::msvc65_like_log_formatter::msvc65_like_log_formatter(boost::unit_test::unit_t est_log const&)' unit_test_log.o: In function `boost::unit_test::unit_test_log::unit_test_log()': unit_test_log.o(.text+0x270): undefined reference to `boost::unit_test::ut_detai l::msvc65_like_log_formatter::msvc65_like_log_formatter(boost::unit_test::unit_t est_log const&)' unit_test_log.o: In function `boost::unit_test::unit_test_log::set_log_format(bo ost::unit_test::basic_cstring<char const>)': unit_test_log.o(.text+0x1000): undefined reference to `boost::unit_test::ut_deta il::msvc65_like_log_formatter::msvc65_like_log_formatter(boost::unit_test::unit_ test_log const&)' unit_test_log.o(.text+0x1056): undefined reference to `boost::unit_test::ut_deta il::xml_log_formatter::xml_log_formatter(boost::unit_test::unit_test_log const&) ' This is from the latest CVS update. Any idea how to fix it? Dave

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RE: [boost] about the "latest news" section [was ATTN: Branch forrelease is scheduled for tonight]
by Brian Braatz 25 Oct '04

25 Oct '04

I would like to also re-submit my request for a spot on the boost main page which has the target for when the next version will be "out". (I am anxiously waiting 1.32) > -----Original Message----- > From: boost-bounces(a)lists.boost.org [mailto:boost-bounces@lists.boost.org] > On Behalf Of Joaquín Mª López Muñoz > Sent: Tuesday, October 19, 2004 8:26 AM > To: boost(a)lists.boost.org > Subject: [boost] about the "latest news" section [was ATTN: Branch > forrelease is scheduled for tonight] > > Aleksey Gurtovoy ha escrito: > > > I'll post another notice right before the branching, and yet > > another one when it's complete. > > > > Regarding the "latest news" section on the main page: > > 1. Shouldn't we adopt the subsection layout as in Boost 1.31, > with "New Libraries", "Updated Libraries", etc.? > 2. Numeric Conversion does not appear listed, yet it is a newly > added library (it shows, though, in the libs page.) > 3. Same for Minmax. > 4. A bio for Herve Bronnimann is uploaded in boost/people, but > it is not linked from boost/people/people.htm. > > I volunteer to take care of this stuff, if no one objects. > > 5. Missing pictures for Fernando Caccional and Hervé. > > Joaquín M López Muñoz > Telefónica, Investigación y Desarrollo >

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[boost][MPL] Numeric metafunctions protocol/infrastructure
by Cromwell Enage 24 Oct '04

24 Oct '04

Once Tropical Storm Jeanne passes away, I should be through with hurricanes for a while. The latest-and-greatest MPL looks great! The new ability to plug in custom numeric metatypes so that they work with existing numeric ops makes it a definite keeper. The part of my sub-library that I've updated to work with the new MPL is at <http://groups.yahoo.com/group/boost/files/mpl_math.zip>, and has been tested with MinGW 3.2 and MSVC 7.1 (2003 Toolkit). Renaming issues aren't too bad; I just have to remember (for one thing) that reverse_copy is defined at copy.hpp and not reverse_copy.hpp as I originally thought. I also noticed that BOOST_MPL_AUX_TYPEOF is no longer there, but I've managed to eliminate the need for it. A major issue I have is how to properly use numeric_cast in order to make something like the following statement work correctly: typedef plus<int_<1>,fraction_c<long,4,3> >::type fraction_7_over_3; Right now I've made N^2 specializations of plus_impl, where N here means the total number of built-in and custom numeric metatypes. For my sub-library, N==4, which means I've made 16 specializations of plus_impl alone! Factor in the comparison ops as well the arithmetic ops, and my code is starting to look bloated. I've supplied a couple of convenience macros to reduce the copy-and-pasting, but I still think I'm missing something crucial here, and I think that something is how to use (or specialize) numeric_cast. Pointers welcome! Cromwell Enage __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - 100MB free storage! http://promotions.yahoo.com/new_mail

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