February 2013 - Boost-users

boost::statechart - two async machines in one process?
by Dick Bridges 03 Mar '13

03 Mar '13

I've been using asynchronous boost::statechart for 5+ years but that doesn't seem to count for much in this instance. I've wrapped myself around the axel and have no idea how to proceed. Any help would be greatly appreciated. I am attempting to create a program that contains two separate classes, each built on a boost::statechart state machine. The classes are similar but there is one-and-only-one class a and it creates instances of class b. At least, that was the plan. (Apologies if this diagram doesn't format correctly. Outlook is NOT being cooperative.) _______________________ ________________________ | boost::statechart | | boost::statechart | |______________________| |________________________| ^ ^ _________|______________ _________|______________ | struct a_statechart | | struct b_statechart | |_______________________| |_______________________| | | _________O____________ __________O___________ | struct a_impl | | struct b_impl | |----------------------------------| |-----------------------------------| | fifo_scheduler sched_ | | fifo_scheduler sched_ | | processor_handle asm_ | | processor_handle bsm_ | | boost::thread thread_ | | boost::thread thread_ | |_____________________| |______________________| | | _________o____________ _________o____________ | struct a | | struct b | |_____________________| |______________________| However, if the class b processor_handle (bsm_) is initialized, the class a state machine doesn't react to *any* events. If I comment out the bsm_ initialization, the class a state machine handles events as expected. If bsm_ is initialized (with our without creating the thread), the class a state machine doesn't respond to any event. The results are exactly the same if bsm_ is assigned in the ctor. Both asm_ and bsm_ are initialized in the ?_impl ctor: [usual stuff]: sched_(true), ?sm_( sched_.create_processor< ?_statechart >() ), thread_() { FWIW, The state machines in both classes are assigned a thread in the ?_impl ctor: boost::thread tmp( bind( &fifo_scheduler<>::operator(), &sched_, 0 ) ); thread_.swap( tmp ); Any assistance will be greatly appreciated. Regards, Dick Bridges The opinions and data in this missive are my own and do not necessarily represent the positions, strategies, or opinions of Western Digital Corporation. IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses. Glenda: http://glenda.cat-v.org/gallery/

2 3

[geometry] how to set number of points / chord length in buffer() join_round strategy?
by John Lilley 03 Mar '13

03 Mar '13

I see in the released buffer() algorithm, there is a chord length argument: void buffer(Input const & geometry_in, Output & geometry_out, Distance const & distance, Distance const & chord_length = -1) But I can't seem to find an equivalent for buffer_inserter<> with a join_round strategy. How do I set the chord length or number of approximating points? John Lilley

2 2

threaded stopwatch or count down timer
by Sean Farrow 03 Mar '13

03 Mar '13

Hi all, I'm currently writing an application that requires either a stopwatch or a countdown timer. Is such a thing available in boost? Any help appreciated. Regards Sean.

3 3

variant with shrink
by Niitsuma Hirotaka 02 Mar '13

02 Mar '13

boost::variant should be variant<int,int> => int variant<int,double> => double variant<int,boost::rational<int> > => boost::rational<int> variant<int,double,std::string> => variant<double,std::string> I wrote such extension https://github.com/niitsuma/variant_shrink

3 4

Fwd: Describing "traits" of a class's members
by Chris Stankevitz 02 Mar '13

02 Mar '13

Hello, A week ago I started a thread here called "Can boost help me organize/parse lots of binary data?" As people started offering help, it because clear I had no idea what I was trying to ask. I come back with a clear question. The attached file defines: 1. TCPosition: an object that describes a position 2. TCDoubleTraits: an object that describes characteristics of a parameter represented as a double 3. TCUnsignedTraits: an object that describes characteristics of a parameter that is represented as an unsigned 4. TCPositionTraits: a collection of TC*Traits plus some boost::function magic to extract parameters from a TCPosition. 5. TCPositionTraits::PrintValues: a function that allows the user to print all values of a TCPosition The motivation for this round-about way of printing the parameters of a "position" is that I have to deal with some objects that have lots of parameters and I would like one central place where I define the characteristics of the values and their order. In this example, that place is TCPositionTraits. In my real life example I will want to store traits such as the way the data is encoded and the way in which the data needs to be transformed into "human readable" format. Question: Can you modify the attached program so that the object TCPositionTraits holds all the traits for the TCPosition object. Not just the traits for the "double" parameters, as is currently the case. Notably missing from TCPositionTraits is a reference to TCPosition::mSteps. Difficulty: This is a difficult question to answer due to the fact that TCPositionTraits has hard-coded in it the keyword "double". I cannot figure out how to remove this. Bonus: Bonus points if your answer looks something like "yes it is possible if you start using a boost concept which you apparently are not aware of". Note: You'll need the C++11 brace-initialization capability to compile this. I used "g++ -std=c++0x test.cpp" with gcc 4.6.3. Thank you, Chris

2 7

[CONFIG] static const definitions
by John M. Dlugosz 01 Mar '13

01 Mar '13

On 2/27/2013 3:13 PM, boost-users-request-at-lists.boost.org |Boost/Allow to home| wrote: > I think it would be great to have a boost macro to test. > If no one else is aware of a readily-available macro in boost config, > maybe you can log a bug and provide a patch to get the ball rolling? > > Brian I've never done that before for Boost. Is there a guide you can point me to, on the correct procedures to follow?

3 2

building boost with a specific msvc runtime
by Tom K. 01 Mar '13

01 Mar '13

I'm trying to get a consistent VC++ runtime for distribution, but I cannot find anything getting boost/bjam to cooperate. I have successfully compiled libcurl and UnitTest++ with the method in this link. http://tedwvc.wordpress.com/2009/08/10/avoiding-problems-with-vc2005-sp1-se… The idea being that you include a header in each file and then it will only have that one runtime dependency. b2 has options for setting cxxflags, though they do not seem to honor my /FI compile option to use the header and force the correct runtime. I assume that they are using something else. I suppose boost doesn't use the msvc flags. How should I accomplish this?

2 4

statistics: exact median, first and third quartile
by gast128 01 Mar '13

01 Mar '13

Hello all, I was looking if Boost would support basic statistics calculated from a container of values: - Boost.Accumulators supports these statistics but only in an incremental way. This is nice, but now we want exact values since the containers are small (i.e. less than 100 elements) - Boost.Math: support only for distributions Did I overlook something or is this just not supported?

3 5

[geometry] getting overlay_invalid_input_exception thrown from union operation
by John Lilley 01 Mar '13

01 Mar '13

I am seeing a overlay_invalid_input_exception thrown from has_self_intersections when calling the union() operation. Does indicate an internal error, or have I not conditioned my input properly? My test is, taking the TIGER 2010 counties file for Alaska, and repeatedly calling union() on the polygons. There may be some issues that I can think of: 1) Island chains are represented as one big multi-ring polygon in the source shape file. When I convert to boost polygon, I set the first ring as the outer, and all others as inners. 2) Aleutians cross the 180-meridian. I am, however, taking steps to force all latitudes into the negative range, but that logic may need to be checked.

3 2

[CONFIG] static const definitions
by John M. Dlugosz 28 Feb '13

28 Feb '13

On 2/27/2013 5:09 AM, boost-users-request-at-lists.boost.org |Boost/Allow to home| wrote: > In fact even when initialized inline, an out of line definition should > always be provided as different compilers have different ideas about what > constitutes "use" of the variable (rather than just the value). MSVC pretty > much never requires an out-of-line definition for example, where as GCC will > often generate linker errors if you don't provide it. The problem is that MSVC is _prohibiting_ an out-of-line definition! (Visual Studio 2010)

3 3