- Boost - lists.boost.org

intrusive_ptr explicit constructor
by Colin Rafferty 25 Oct '04

25 Oct '04

Hi- Shouldn't the constructor in intrusive_ptr be explicit? explicit intrusive_ptr(T * p, bool add_ref = true): p_(p) { if(p_ != 0 && add_ref) intrusive_ptr_add_ref(p_); } I don't have cvs access. -- Colin

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[assign] typo
by Jonathan Turkanis 25 Oct '04

25 Oct '04

Dear Thorsten, It was good to meet you finally last week. I'm reading through the assign docs and there seem to be some misplaced parentheses in the definition of names2 in the preformatted section following the heading "Function list_of()". I think it should say const stack<string> names2 = list_of( "Mr. Foo", "Mr. Bar", "Mrs. FooBar" ).to_adapter(); Best Regards, Jonathan

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[contacting Jeremy B. Maitin-Shepard]
by Thorsten Ottosen 25 Oct '04

25 Oct '04

Dear All, I have troubles getting in contact with Jeremy and I want to discuss some hash-table stuff with him. Does anyone know his email? br Thorsten

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[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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