June 2006 - Boost-users - lists.preview.boost.org

Re: [Boost-users] multi_array: creating a view to a single element
by Sohail Somani 29 Jun '06

29 Jun '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Cromwell Enage > > > Would T & center = element[3][3] be satisfactory? > > Try: > > typename boost::multi_array<T,2>::index > index1 = (element.index_bases()[0] > + element.strides()[0]) / 2; > typename boost::multi_array<T,2>::index > index2 = element.index_bases()[1]; > + element.strides()[1]) / 2; > T& center = element[index1][index2]; To make it general, yes. > > I don't think multiarray supports any type of > > reallocation after construction, so it should > > be ok. > > boost::multi_array has a resize() function, if that's > what you're afraid of. See > <http://www.boost.org/libs/multi_array/doc/reference.html> In this case, obviously center would not be center anymore, so the OP should beware.

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[date_time] Get age in years
by Jason Dolan 29 Jun '06

29 Jun '06

I'm trying to get the age of someone in Years and/or months and/or days. I've tried: date_period dp(day_clock::local_day(), birthdate); cout << "You are " << dp.length() << " old" << endl; But that only calculates days. Is there a static function available that will turn days into months. and days into years? Thanks -Jason

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Re: [Boost-users] multi_array: creating a view to a single element
by Sohail Somani 29 Jun '06

29 Jun '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Baranowski, Daniel > Sent: Wednesday, June 28, 2006 7:55 PM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] multi_array: creating a view to a > single element > [snip] > Basically, I have a 2 Dimensional array and I > would like to be able to access the center of that array > using a variable that maps to some index (for example, > element[3][3] in a 7x7 array). [snip] Would T & center = element[3][3] be satisfactory? I don't think multiarray supports any type of reallocation after construction, so it should be ok. Sohail

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Embedded Python issue
by Trevor M Cickovski 29 Jun '06

29 Jun '06

Hello, I am trying to run some embedded Python code, following the boost.Python tutorial. What I was hoping to do was import some external modules. So basically in my .cpp file I have: Py_Initialize(); object main_module(( handle<>(borrowed(PyImport_AddModule("__main__"))))); object main_namespace = main_module.attr("__dict__"); try{ handle<> ignored((PyRun_String( "import Numeric\n" // Other Python commands , Py_file_input , main_namespace.ptr() , main_namespace.ptr()) )); } catch(error_already_set) { PyErr_Print(); } // Finish the Python Interpreter Py_Finalize(); However when I 'import Numeric', I get an undefined symbol: Traceback (most recent call last): File "<string>", line 4, in ? File "/afs/nd.edu/user25/tcickovs/Research/PYTHON/lib/python2.4/site-packages/Numeric/Numeric.py", line 91, in ? import multiarray ImportError: /afs/nd.edu/user25/tcickovs/Research/PYTHON/lib/python2.4/site-packages/Numeric/multiarray.so: undefined symbol: PyExc_ValueError Now if I just run python from the command line and call 'import Numeric' everything is fine. Does anyone have any idea what I need to do differently if I use Boost? Thanks for the help, Trevor -- ------------------------------------------------------- This is your time, this is your dance Live every moment, leave nothing to chance. Swim in the sea, drink of the deep Embrace the mystery of all you can be. - Michael W. Smith, "This Is Your Time"

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Re: [Boost-users] boost 64bit support on windows x64 on amd64 hardware
by Sohail Somani 29 Jun '06

29 Jun '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of ChuMing > > > > On Tuesday, June 27, 2006 at 08:42:30 (+0000) Chu-Ming Ng writes: > > > > > >Hi, > > > > > >I am porting some code that uses boost from 32-bit to the > 64-bit platform > and > > >would like to know if the boost library supports this platforms. > But is there anyone I can ask to for official > confirmation? You can confirm it for yourself by looking at the regressions linked from the www.boost.org page. Or run them yourself.

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how to compile first.cpp example
by francis 29 Jun '06

29 Jun '06

Hello, I try to compile first.cpp with bjam, but I don't know ho to specify the program_options library. I have a binary release of the boost library (Linux Kubuntu). I'm looking for a good Jamfile. Thanks for your help.

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Statechart: Comple error with MinGW and not MSVC-7.1
by Eoin 29 Jun '06

29 Jun '06

Hello, My name is Eoin O'Callaghan I've run into a difficulty with the Boost Statechart library as I was porting my code from MSVC-7.1 to work with MinGW also. MinGW gives an error regarding the ctx parameter used with non simple states when the state is a template class; MinGWFail.cpp:24: error: expected `)' before "ctx" MinGWFail.cpp:29: error: expected constructor, destructor, or type conversion before '(' token I've attached a small file which replicates the problem. Note that if the content state is a simple_state then both MSVC-7.1 and MinGW compile without errors. Hope someone can make some sense of this, thanks the the author for making such an excellent library free for everyone. (Indeed thanks to all those involved in Boost :) ) Kind regards, Eoin. #include <boost/statechart/event.hpp> #include <boost/statechart/state_machine.hpp> #include <boost/statechart/state.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/transition.hpp> #include <boost/statechart/custom_reaction.hpp> template<class P> class content; class parser : public boost::statechart::state_machine<parser, content<parser> > { public: parser(); virtual ~parser() {} }; template<class P> struct content : boost::statechart::state<content<P>, P> { public: content(my_context ctx); virtual ~content() {} }; template<class P> content<P>::content(my_context ctx) : my_base(ctx) {}

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multi_array: creating a view to a single element
by Baranowski, Daniel 29 Jun '06

29 Jun '06

Hey All! I'm sure there's got to be a way, and unfortunately, the boost users archive is "down for maintenance" so I can't search there. Basically, I have a 2 Dimensional array and I would like to be able to access the center of that array using a variable that maps to some index (for example, element[3][3] in a 7x7 array). Can someone tell me how to do this? I tried to create a view to a 0 Dimensional array, but that wouldn't work (not surprisingly). FWIW, here's what I tried: array_type::array_view<0>::type center(myarray[ boost::indices[3][3] ]); I can do this: Array_type::array_view<1>::type center(myarray[ boost::indices[range(3,3)][3] ]); But then I access the center by doing center[0]... I guess that'll work, but I wouldn't consider that ideal. Anyone? Anyone? Bueller? Bueller? Thanks a bunch! Daniel ********************************************************************************************** Disclaimer - This email and any files transmitted with it are proprietary and may contain privileged or copyright information. You must not present this message to another party without gaining permission from the sender. If you are not the intended recipient you must not copy, distribute or use this email or the information contained in it for any purpose other than to notify us. If you have received this message in error, please notify the sender immediately, and delete this email from your system. We do not guarantee that this material is free from viruses or any other defects although due care has been taken to minimize the risk. eSafe scanned this email for viruses, vandals and malicious contentAny views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of LSI. **********************************************************************************************

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Re: [Boost-users] shared_ptr in a boost::any [config] [hpux]
by Thomas Matelich 28 Jun '06

28 Jun '06

On 6/27/06, David Abrahams <dave(a)boost-consulting.com> wrote: > "Thomas Matelich" <matelich(a)gmail.com> writes: > > > I use boost::any for sending data to my thread's command queue, and I > > need to send a shared_ptr in. I'm looking for any one to tell me this > > is fine or bad. Based on my understanding of boost::any I think it > > will be fine, but I'm slightly concerned I'll screw up the reference > > count somehow. > > > > Can anyone confirm or allay my fears? > > Allay :) Thanks. Unfortunately, I just ran into boost/config/platforms/hpux.hpp and its belief that gcc and threads don't mix on HP-UX. I'm not sure why this is stated. Perhaps its left over from HP 10.x and DCE threads? I've been using gcc and threads for a long time, even back on 10.20 using ACE. I currently use both ACE thread wrappers and Qt's threads wrappers on 11i with gcc 3.2.3. I would just go ahead and comment out that assumption, but I'm concerned someone knows something I don't know. It looks like Jens Maurer added this assumption 2 years ago ( http://tinyurl.com/ku9wm ). Has anyone experimented with removing it? I'd really like mutexes for my shared pointers. Short-term, I'm currently working on a patch release and wouldn't really want to mess with every shared pointer in my whole system. I guess my workaround would be to wrap the shared_ptr in a mutexed_shared_ptr and lock every option that messes with the shared count?

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Re: [Boost-users] [date_time] extract date from string using a list of patterns
by Brian Neal 28 Jun '06

28 Jun '06

> Thats why I was looking into it this way, I was hoping not to have to > create my own parser. I'm actually kinda of surprised that there isn't > a open source natural language date string parser out there already. GNU date is such a library. In PHP, there is the strtotime() function, which I believe uses GNU date C code to parse stuff like what you list. It accepts a bewildering variety of strings like "now", "last Monday", "10 September 2004", "10 Sep 2004", "+1 week 2 days 3 seconds", etc. I can't find a GNU link for you though. But here is the man page for PHP's strtotime() for a starting point: http://us3.php.net/manual/en/function.strtotime.php Good luck

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