May 2003 - Boost-users - lists.boost.org

const shared_ptr<>
by Hossein Haeri 02 May '03

02 May '03

Dear all, I'm a newbie in boost! I want to know what the following means: int a = 5; const boost::shared_ptr<int> sp(&a); Does it mean that the following line is an error? *sp = 7; If so, what are the guarantees? Is there any documented guarantee? (I couldn't find anything in the documentation. Excuseme if I'm careless!) Thanks, --Hossein __________________________________ Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. http://search.yahoo.com

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RE: [Boost-Users] Is there a "known issues" page anywhere?
by Jim.Hyslop 02 May '03

02 May '03

Alisdair Meredith [mailto:yg-boost-users@gmane.org] wrote: > Is there a place where known problems for libraries/compilers are > stored? > > For instance, trying to use boost/time we hit a problem with MSVC7 and > lexical_cast unless we enable the "wchar_t as a native type" option. > While this may be good practice <g> it is not the default, > and caught us > out (and the error is none-too helpful) > > I can imagine this sort of issue is discovered and re-discovered on a > regular basis, and wonder where to look for such known issues before > using list bandwidth. There is a "Known Issues" section on the wiki (see the link in the auto-appended .sig) which is intended to document these common "gotchas". I haven't looked at it for a while, so I don't know how up-to-date it is. If that issue's not documented there, would you mind adding it? -- Jim

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graph (BGL): bad documentation
by schlumpfi106 01 May '03

01 May '03

I just tried to use the boost graph library to create a spanning tree generation algorithm. After wasting a whole day I gave up and wrote all the graph code myself. I'm quiet upset about the useless online documentation for the graph library. Maybe I have to buy the book to be able to use it? Normally I would rely on some good, instructive examples and start my own program by copy-and-paste. Here, there are only a few examples and they are either too simple or too specific. Most documentation topics provide no examples at all. Sometimes I head to guess through the template-loaded headerfiles because there was no documentation. I failed in creating a graph from a given adjacency matrix. I failed in understanding the "interior property" concept. I failed in printing a graph and its properties to graphviz. To the developers: Please, before you implement anything new -- document the old things.

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RE: [Boost-Users] Regexp Homework :-)
by Ben Hutchings 01 May '03

01 May '03

Simon Brown <simon.brown(a)kns.ch> wrote: > A few days ago I received great help with a regexp question - > now here's > another which I doubt can be done. > > Question: if the text string contains three words AAA BBB AAA > then return > the string (if any) which is repeated two or three times. > > Examples: > AAA AAA AAA return AAA > AAA BBB AAA return AAA > AAA AAA BBB return AAA > AAA BBB CCC return <nothing> > > Can this be done with a regular expression? Match against "(\\w+) (?:\\1 \\w+|\\w+ \\1)|\\w+ (\\w+) \\2" and return the match for whichever sub-expression (1 or 2) was matched. (I tested this with Python not Boost regex, but they should be compatible.)

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Is there a "known issues" page anywhere?
by Alisdair Meredith 01 May '03

01 May '03

Is there a place where known problems for libraries/compilers are stored? For instance, trying to use boost/time we hit a problem with MSVC7 and lexical_cast unless we enable the "wchar_t as a native type" option. While this may be good practice <g> it is not the default, and caught us out (and the error is none-too helpful) I can imagine this sort of issue is discovered and re-discovered on a regular basis, and wonder where to look for such known issues before using list bandwidth. -- AlisdairM

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regexp match question
by Simon Brown 01 May '03

01 May '03

Hi All, Here's a question I can't answer. I'm using regexp to dig out strings from data received via Ham Radio, so the txt often is corrupted. What I want to match is two consecutive callsigns separated by whitespace, for example 'hb9drv hb9drv' but not 'hb9drv hb9drX'. I can define the match condition for a callsign, but can I use the match option {2,3} somehow to match the same callsign two or three times? Effectively match the same word two or three times? Help received with much thanks, Simon Brown, Casa Bergenia, CH-7031 Laax www.hb9drv.ch [Non-text portions of this message have been removed]

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