- Boost-users - lists.boost.org

mem_fn and references?
by Duane Murphy 25 Jan '02

25 Jan '02

I am trying to make a member function call to all objects returned by an iterator. mem_fn is giving me an error when trying to call get_pointer() for a reference object. There is no overload for get_pointer of a reference object. Is there some reason or should I be doing this differently. The long description is that I am iterating over a container of objects. I would like to make a member function call on each of these objects. Then I get an error that there is no matching function for get_pointer( obj ). I have solved this by providing my own get_pointer() overload specifically for obj to prevent any bad things from happening until I can found out what the real problem is. Here is some pseudo code to get things in the right orientation. class obj { public: void method(); }; class obj_iterator { public: obj& iterator::operator*() const { return obj_; } }; class obj_container { public: obj_iterator begin(); obj_iterator end(); } { ... obj_container c; foreach( c.begin(), c.end(), mem_fn( method ) ); } Thanks, ...Duane

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Solaris/sparcWorks 5.0
by sebmarc 24 Jan '02

24 Jan '02

Does anybody know how to compile boost with Solaris 7 and sparcWorks 5.0. Looking at http://www.boost.org/tools/build/index.html, there is no place for this compiler. Any help appreciated. Thanks, Seb.

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RE: [Boost-Users] Subject: Poll results for Boost-Users
by Tom Matelich 24 Jan '02

24 Jan '02

I asked the original question that sparked this, and its because (at the root) I want to know whether feature requests need to be mirrored on the main boost list. So if I can be sure that the author of the library is at least listening to my boost-users message, I don't have to CC him/her or spam both lists. That is why I wanted access to the members, and as a support mechanism, why I thought it was important for boost-users. I realize membership != reading the messages, so perhaps my point is moot. > -----Original Message----- > From: Jim.Hyslop [mailto:jim.hyslop@leitch.com] > Sent: Wednesday, January 23, 2002 7:20 AM > To: 'Boost-Users(a)yahoogroups.com' > Subject: RE: [Boost-Users] Subject: Poll results for Boost-Users > > > Chris Little [SMTP:clittle@renlearn.ca] wrote: > > When the question first came up of allowing members to view > the membership > > list, one of the moderators started a poll (around the beginning of > > January). > That'd be me. > > > Unfortunately polling in this group is limited to moderators. > > The moderators then decided to discuss the issue amongst > themselves and > they > > haven't reported back. > > Hoo, boy, I seem to have dropped the ball on several counts here. > > First, my apologies for not cancelling the poll after > discovering polling > was limited to moderators. > > Second, my apologies for not reporting back to the group on > the results of > our discussion (I'm taking responsibility for this, since I'm > the one who > opened the can of worms in the first place). > > We identified a potential problem with spam email harvesting. > Granted, in > the public pages emails are hidden, so that only the first > letter of the > domain appears (my address, for example, would appear as > "jim.hyslop@l..." > One of the moderators pointed out: > > > About half of the email addresses on > > the first page start with either an a, h, or y. > > ... the problem is that when harvesting email addresses you > > don't need 100% accuracy. Just assume that a's are aol, all b's are > > bigfoot, all e's are earthlink, all h's are hotmail.com, > and all y's > > are yahoo.com. These letters are going to be [greater than] > half the list > and you > > will be correct [greater than] half the time. > > We could not come up with any compelling arguments in favour > of opening the > list. I believe the best summary was: > > > I'm not sure what the benefits of public membership would be. > > Arguments such as "I need to know if X is a member of > > the group" seem empty - this is a *mailing list* after all. > > To access individuals, you should get hold of them in > > other ways. If they are active members of the list, you'll > > still know they're members. > > No moderators actually spoke out in favour of opening the > list up, so the > status quo remains. > > We moderators are, of course, open to suggestions, and if a reasonably > strong argument comes up, then we will re-examine the issue. > If anyone feels > strongly about it, you can either post your rationale here or > email the > moderators at boost-users-owner(a)yahoogroups.com (the > 'boost-users-owner' > name is a bit misleading - email goes to all moderators, not > just to the > owner). > > Similarly, on the topic of polls themselves, the general > consensus was that > if or when we identify a good reason to run a poll, then we > will open up the > feature. Until then, there's no reason to change the status quo. > > -- > Jim > > > ------------------------ Yahoo! Groups Sponsor > ---------------------~--> > Tiny Wireless Camera under $80! > Order Now! FREE VCR Commander! > Click Here - Only 1 Day Left! > http://us.click.yahoo.com/nuyOHD/7.PDAA/yigFAA/EbFolB/TM > -------------------------------------------------------------- > -------~-> > > Info: <http://www.boost.org> > Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> > Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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Re: [BGL] BFS and copy problem (was Re: [boost] Compilation)
by Jeremy Siek 24 Jan '02

24 Jan '02

Again, Luca, we can't help you unless you post the code (the complete C++ file). I can't just guess what is going wrong. You're probably forgetting to do something, and there's no way I can tell what that is based on what you've written below. On Thu, 24 Jan 2002, lucatoldo wrote: luca.t> I think there is something I do not know, rather important, about the luca.t> process of adding edges to the graph object. Infact, even in the luca.t> simple example/bfs.cpp if I swap the start with the ends, I get luca.t> different results. Namely: luca.t> luca.t> If I change the code from this luca.t> luca.t> boost::add_edge(0,2,G); luca.t> boost::add_edge(1,1,G); luca.t> boost::add_edge(3,1,G); luca.t> ... luca.t> boost::add_edge(4,1,G); luca.t> luca.t> to luca.t> luca.t> boost::add_edge(2,0,G); luca.t> boost::add_edge(1,1,G); luca.t> boost::add_edge(1,3,G); luca.t> ... luca.t> boost::add_edge(1,4,G); luca.t> luca.t> then I get luca.t> luca.t> the graph OK but the distances and the parent vectors are screwed: luca.t> luca.t> I get luca.t> luca.t> distances: 0 2 2 2 1 luca.t> instead of luca.t> distances: 0 2 1 2 2 luca.t> luca.t> and luca.t> luca.t> parent[0] = 0 luca.t> parent[1] = 4 luca.t> parent[2] = 4 luca.t> parent[3] = 4 luca.t> parent[4] = 0 luca.t> luca.t> instead of luca.t> luca.t> parent[0] = 0 luca.t> parent[1] = 2 luca.t> parent[2] = 0 luca.t> parent[3] = 2 luca.t> parent[4] = 2 luca.t> luca.t> I feel I am missing some basic knowledge on how to appropriately use luca.t> this powerful and amazingly fast system. I would love to learn the luca.t> missing bit. luca.t> luca.t> Looking forward your advice and sorry again for the dumminess of this luca.t> question. luca.t> luca.t> luca.t> Info: http://www.boost.org Send unsubscribe requests to: <mailto:boost-unsubscribe@yahoogroups.com> luca.t> luca.t> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ luca.t> luca.t> ---------------------------------------------------------------------- Jeremy Siek http://php.indiana.edu/~jsiek/ Ph.D. Student, Indiana Univ. B'ton email: jsiek(a)osl.iu.edu C++ Booster (http://www.boost.org) office phone: (812) 855-3608 ----------------------------------------------------------------------

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RE: [Boost-Users] Subject: Poll results for Boost-Users
by Jim.Hyslop 24 Jan '02

24 Jan '02

Tom Matelich [SMTP:tmatelich@zetec.com] wrote: > I asked the original question that sparked this, and its because (at the > root) I want to know whether feature requests need to be mirrored on the > main boost list. So if I can be sure that the author of the library is at > least listening to my boost-users message, I don't have to CC him/her or > spam both lists. The moderators have agreed that one of our duties will be to ensure appropriate cross-pollination of messages. In other words, if a discussion here in Boost-Users raises an issue that is appropriate to the main Boost list (such as a feature request or a bug report), we will ensure it gets forwarded to that forum. Similarly, if someone posts a message to Boost that is more appropriate to this list, we will encourage the original poster to switch to this forum. -- Jim

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Adding edges to a graph. Problems.
by lucatoldo 24 Jan '02

24 Jan '02

I think there is something I do not know, rather important, about the process of adding edges to the graph object. Infact, even in the simple libs/graph/example/bfs.cpp if I swap the start with the ends, I get different results. Namely: If I change the code from this boost::add_edge(0,2,G); boost::add_edge(1,1,G); boost::add_edge(3,1,G); ... boost::add_edge(4,1,G); to boost::add_edge(2,0,G); boost::add_edge(1,1,G); boost::add_edge(1,3,G); ... boost::add_edge(1,4,G); then I get the graph OK but the distances and the parent vectors are screwed: I get distances: 0 2 2 2 1 instead of distances: 0 2 1 2 2 and parent[0] = 0 parent[1] = 4 parent[2] = 4 parent[3] = 4 parent[4] = 0 instead of parent[0] = 0 parent[1] = 2 parent[2] = 0 parent[3] = 2 parent[4] = 2 I feel I am missing some basic knowledge on how to appropriately use this powerful and amazingly fast system. I would love to learn the missing bit. Looking forward your advice and sorry again for the dumminess of this question.

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A tip from the Dr.
by jackthompson99 23 Jan '02

23 Jan '02

Hey guys, I sent an e-mail to Dr. Stroustrup a couple nights ago, and he replied, "Have a look at boost.org. They exist specifically to provide better libraries in the context of the C++ standard library and to act as a test bed for new library ideas". So, here I am. I've installed and built my boost libraries, and I'm trying to figure out how to dig in. Anyway, here's what I was telling the Dr. I've been using C for about a decade, and C++ for about 7 yrs. I'm a huge fan of your invention, and I honestly feel like your name should eventually be as well known as Tesla and Edison. And the Standard Template Library is an incredibly well engineered system. I have a way to use it that is generic enough that it may be a candidate to be another standard. I know that's a lot to say. I'd like to explain it briefly, but first I should explain why I find it useful. Since I started working with assembler, I've always felt like the language I was using was missing something. I've used an assortment of languages, and it seems like they are all missing the same thing. The main part isn't really missing from C++, it's just not commonly understood. The concept of virtual construction is the core of the issue. Now I know that this problem is solved, but it really could stand for just one more thing to wrap it up into something usable for any ordinary C++ developer. Using a virtual constructor by way of a template, a developer can easily create any kind of object based on any type of identifier, but what good is that when the developer has exhausted all of his efforts on just building a simple system to dynamically create objects. The developer needs a way to organize these objects, without building another data warehouse. And I have never heard of a complicated database that shouldn't be fully hierarchical. So, the system should be one hundred percent re-entrant. Well, I have such a beast. I'm not done with it yet. I'm just now finishing up a project for Textron, where some of this concept was cultivated into my skill set. I am having a rough time explaining the system to my boss, and I'm in a real bind, but that's another story. The main thing that I've learned from this job is that the world needs to come together on one simple international standard for dealing with data and persistent C++ objects. I've used my ClassFactory / DataStore system as a foundation for another library that I call the WinFactory. This system simply uses the ClassFactory / DataStore as a database manager. The objects held in the database are simply graphical user interface components. This worked out really well, `till by boss took it apart. But I have a version of it that I'm re-writing at home that is much better. The database can be held either in a simple text format, resembling hypertext, or a binary file. The system relies heavily on the memory manager, so fast memory allocation is required. I have also populated an MFC user interface with data held in these objects. The system seems to be able to flex with just about anything, and I feel like it could at least contribute to discussions about new standards that are based on your standards. By the way, I need to find a team that I can work with who has good work ethics and integrity. Suggestions would be much appreciated. ..... So, I've looked at the library list in Boost, and haven't recognized anything like what I've built. I would love to explain this system. But, again, this one belongs to Textron, and all of the documentation too. I need to find some time to build this system for Boost.org. The main concept behind the system is a warehouse environment. The warehouse hase isles of goods. Each isle is any length, and each isle contains exactly one type of product. And every product contains a single pointer which is initally NULL. This makes it so that when you pull the product off the shelf and open it, you will see whatever the product is ( characters, integers, strings, etc. ), and you will find one more thing. It's called the nest. Now, until you try to use the nest, it's empty (NULL). But when you need it, it is created. What is this nest you ask? It's another warehouse. Just like the one that it is contained within. So, the entier concept is one hundred percent re-entrant. This makes it easy to build hierarchical infrastructures. The objects can be virtually any C++ thing. They persist with the greatest of ease to simple IO objects. User interfaces are easy to build with this system. Content editors view it as a script. C++ programmers view the script as C++ objects. Again, I need to finish re-writing the system, and I need to document it. But I feel like it is a candidate to become another Boost library. What do you think?????

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RE: [Boost-Users] Subject: Poll results for Boost-Users
by Jim.Hyslop 23 Jan '02

23 Jan '02

Chris Little [SMTP:clittle@renlearn.ca] wrote: > When the question first came up of allowing members to view the membership > list, one of the moderators started a poll (around the beginning of > January). That'd be me. > Unfortunately polling in this group is limited to moderators. > The moderators then decided to discuss the issue amongst themselves and they > haven't reported back. Hoo, boy, I seem to have dropped the ball on several counts here. First, my apologies for not cancelling the poll after discovering polling was limited to moderators. Second, my apologies for not reporting back to the group on the results of our discussion (I'm taking responsibility for this, since I'm the one who opened the can of worms in the first place). We identified a potential problem with spam email harvesting. Granted, in the public pages emails are hidden, so that only the first letter of the domain appears (my address, for example, would appear as "jim.hyslop@l..." One of the moderators pointed out: > About half of the email addresses on > the first page start with either an a, h, or y. > ... the problem is that when harvesting email addresses you > don't need 100% accuracy. Just assume that a's are aol, all b's are > bigfoot, all e's are earthlink, all h's are hotmail.com, and all y's > are yahoo.com. These letters are going to be [greater than] half the list and you > will be correct [greater than] half the time. We could not come up with any compelling arguments in favour of opening the list. I believe the best summary was: > I'm not sure what the benefits of public membership would be. > Arguments such as "I need to know if X is a member of > the group" seem empty - this is a *mailing list* after all. > To access individuals, you should get hold of them in > other ways. If they are active members of the list, you'll > still know they're members. No moderators actually spoke out in favour of opening the list up, so the status quo remains. We moderators are, of course, open to suggestions, and if a reasonably strong argument comes up, then we will re-examine the issue. If anyone feels strongly about it, you can either post your rationale here or email the moderators at boost-users-owner(a)yahoogroups.com (the 'boost-users-owner' name is a bit misleading - email goes to all moderators, not just to the owner). Similarly, on the topic of polls themselves, the general consensus was that if or when we identify a good reason to run a poll, then we will open up the feature. Until then, there's no reason to change the status quo. -- Jim

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RE: [Boost-Users] Subject: Poll results for Boost-Users
by Chris Little 23 Jan '02

23 Jan '02

When the question first came up of allowing members to view the membership list, one of the moderators started a poll (around the beginning of January). Unfortunately polling in this group is limited to moderators. The moderators then decided to discuss the issue amongst themselves and they haven't reported back. Chris > -----Original Message----- > From: James Curran/MVP [mailto:jamescurran@mvps.org] > Sent: Wednesday, January 23, 2002 8:29 AM > To: Boost-Users(a)yahoogroups.com > Subject: RE: [Boost-Users] Subject: Poll results for Boost-Users > > > How long was that poll open for? > > Truth, > James Curran > > > -----Original Message----- > From: Boost-Users(a)yahoogroups.com > [mailto:Boost-Users@yahoogroups.com] > Subject: Poll results > for Boost-Users > > > The following Boost-Users poll is now closed. Here are the > final results: > > > CHOICES AND RESULTS > - I want only the moderators to be able to view the > membership list, 0 votes, 0.00% > - I want anyone to be able to view the membership list, 0 > votes, 0.00% > [Non-text portions of this message have been removed]

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RE: [Boost-Users] Subject: Poll results for Boost-Users
by James Curran/MVP 23 Jan '02

23 Jan '02

How long was that poll open for? Truth, James Curran -----Original Message----- From: Boost-Users(a)yahoogroups.com [mailto:Boost-Users@yahoogroups.com] Subject: Poll results for Boost-Users The following Boost-Users poll is now closed. Here are the final results: CHOICES AND RESULTS - I want only the moderators to be able to view the membership list, 0 votes, 0.00% - I want anyone to be able to view the membership list, 0 votes, 0.00%

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