- Boost-users - lists.boost.org

[thread] Priority?
by Ovanes Markarian 10 Mar '08

10 Mar '08

Hello, I used boost thread library a lot and like it very much. Currently, I was reading the C++ Standerd proposal and saw that a thread (as well as boost::thread) does not have a priority. Which reason was it not to implement the thread priority in boost, and why is it not considered in the upcoming standard? I understand this feature is rarely required, but if someone suddenly needs to start a real-time priority thread he/she will be forced to use a third party lib again. Or is there smth. what I miss? Many thanks, Ovanes

4 6

[statechart] Getting state information into the machine
by Commander Pirx 10 Mar '08

10 Mar '08

I'm using the Statechart Library in conjunction with the really exciting Asio Library to set up a communication server. There is a very helpful documentation of the Statechart Library too. But one topic is puzzling me: How to to get data into the state machine? Here is an simple example: Each session object of the server has two states: signed-off and authorized. Receiving a login event leads to a transition to the authorized state. Thats pretty easy. But the login data (stored in the login event) got lost. I can hold this data in the state machine itself (outermost_context()). Or I can use a pseudo event to forward this data to the authorized state. But I'm looking for a nifty way to avoid this overhead. I like this concept of state-local storage very much. But I'm not shure about how to use it.

2 2

Query state on an asynchronous_state_machine
by Jarl Friis 10 Mar '08

10 Mar '08

Hi. Can anyone tell me how to query a state on an asynchronous_state_machine? The obvious answer would be to say use the state_downcast method (which is inherited from state_machine. But in practise it seems harder than so. But opposed to state_machine, when using asynchronous_state_machine the instance is not created explicitely, it is created implicitely by the scheduler, like this: myMachine = myEventHandler.create_processor<AsyncMachine>(); , hence there is no handle to the state machine itself. All I have is a handle to the processor (sc::fifo_scheduler<>::processor_handle ). So is there a way to come from sc::fifo_scheduler<>::processor_handle to AsyncMachine (which inherits sc:asynchronous_state_machine)? Jarl

2 2

[Boost.Iterators] iterator_facade + a class design issue
by Ashkan Aliabadi 10 Mar '08

10 Mar '08

Dear all, I've decided to write an ABC named BasicIterator, from which all derived iterators are to be descended. The reason being that I have to refer to iterators inside an interface and I need a general base type as a place holder to which I can refer. Besides, I don't want to use CRTP in the interface, but I don't care if I'm forced to use it inside BasicIterator. As discussed in the interoperability section of iterator_facade (here<http://www.boost.org/libs/iterator/doc/iterator_facade.html#interoperability>), the euqal() function must be templatized. The problem is that I have to make equal() a pure virtual member function in order to force derived types override it, but templated virtual functions on the other hand, are not valid. So I was wondering what the best approach is. How can I achieve both of these goals? Please advise. Any ideas/suggestions are welcome. Thanks in advance

2 4

[signals] callback for synchronization, how to do?
by Rainer Thaden 10 Mar '08

10 Mar '08

Hi all, maybe a simple question, but I just can't figure it out: I have a class which triggers an action on a remote device. A different thread polls for the response and sends a signal that the response has arrived. What I simply want is a blocking call like this: // connect to the signal which reports the response otherClass.sigResponse().connect( some sort of lamda magic?) SendCommand(cmd); // Wait somehow until the response has arrived WaitForSigResponse(); return; Any help appreciated. Thanks, Rainer

1 0

remove_copy_if adapted as copy_if
by PJ Durai 09 Mar '08

09 Mar '08

Can anyone with advanced template-fu show me to an adaptation of remove_copy_if to be copy_if ? I do realize you just have to negate the predicate parameter of remove_copy_if. I would prefer to use a function that does that automatically, since the code would be easier for my co-workers to follow. thanks pj

2 1

boost exceptions on MacOS 10.5
by Lothar May 09 Mar '08

09 Mar '08

Hi, I've brought this up before, but I still have no solution for this issue, so I will give it another try: Does anyone have boost 1.34.1 compiled on MacOS 10.5 where exceptions can be caught? You might use the following code to test: --cut here-- #include <iostream> #include <boost/filesystem.hpp> using namespace std; using namespace boost::filesystem; int main() { try { directory_iterator i("does_not_exist"); } catch(...) { cout << "This is never printed on MacOS 10.5." << endl; } return 0; } --cut here-- If this works with your installation of boost on MacOS 10.5, please tell me which steps you did to compile boost, and whether you used the static or dynamic version. A related question is: Is boost "supposed to work" on MacOS 10.5? Thanks, Lothar

4 16

Pion Network Library 0.5.4
by Michael Dickey 09 Mar '08

09 Mar '08

In conjunction with the first alpha release of our Pion CEP Platform, Atomic Labs is happy to announce a new release (v0.5.4) of the Pion Network Library, an active, fully-functional and Boost-licensed HTTP 1.0/1.1 client/server library built on top of asio. This new release contains several enhancements, including the ability to define alternative thread management and work scheduling for each server instance (PionScheduler is no longer a singleton), and the ability to bind any function object (or function if you use boost::bind) to an HTTP resource (the use of WebService plugins is now optional). We've also added a std::basic_iostream wrapper for TCPConnection objects called TCPStream. In addition, we fixed several bugs that were identified within the last (v0.5.2) release, including issues with parsing chunked entity content, and with parsing responses that include neither "Content- Length" nor "Transfer-Encoding" HTTP headers. Also, the HTTPRequest and HTTPResponse objects now sort HTTP headers using a case- insensitive map, so lookups should now work properly regardless of the capitalization used (if any). Although we have several new things planned for the next few months (such as adding support for user authentication), the networking library is now mostly stabilized and ready for general use. The Pion CEP Platform is open source software, published under the GNU Affero GPL license. The platform is a real-time event processing engine that is designed to be extremely extensible through the use plugins. Plugins can be developed to provide specialized data processing logic, web services, and to enable support for different data encoding formats and databases. You can learn more and download releases at http://www.pion.org Take care, -Mike

1 0

[Review] Reminder: Proto review half way through now
by Hartmut Kaiser 09 Mar '08

09 Mar '08

Hi all, this is just a gentle reminder that currently we have the Proto review ongoing. It will last another week and will end on March 14th. We have not got enough response so far! If you're planning to submit a review, please do so soon. If you didn't have considered to submit one yet, please reconsider! Here is the initial announcement: The review of Eric Nieblers Proto library starts today, March 1st 2008, and will end on March 14th. I really hope to see your vote and your participation in the discussions on the Boost mailing lists! --------------------------------------------------- About the library: Proto is a framework for building Domain Specific Embedded Languages in C++. It provides tools for constructing, type-checking, transforming and executing expression templates. More specifically, Proto provides: * An expression tree data structure. * Operator overloads for building the tree from an expression. * Utilities for defining the grammar to which an expression must conform. * An extensible mechanism for immediately executing an expression template. * An extensible set of tree transformations to apply to expression trees. * A mechanism for giving expressions additional behaviors and members. Documentation is here: http://boost-sandbox.sourceforge.net/libs/proto Download proto.zip from here: http://www.boost-consulting.com/vault/index.php?directory=Template%20Metapro gramming Proto is a very important infrastructure library, IHMO. It has been used as the backbone for several other library writing efforts already, such as Xpressive and the rewrite of Spirit (there it has been used for all three parts: the parser, the lexer and the generator modules), and it is a key enabling technology in the long-planned unification of Phoenix and the Lambda Library. --------------------------------------------------- Please always state in your review, whether you think the library should be accepted as a Boost library! Additionally please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Regards Hartmut Review Manager

1 0

error: 'level' is not a member of 'boost::logging::formatter'
by Brad 09 Mar '08

09 Mar '08

Hello all, First post so be gentle with me :-) OK, I've been playing around with revision 43544 of boost::logging using the following code; #include <boost/logging/format.hpp> #include <boost/logging/format/formatter/tags.hpp> #include <boost/logging/format/destination/syslog.hpp> // uncomment if you're using Named Formatters and Destinations // #include <boost/logging/format/named_write.hpp> using namespace boost::logging; typedef boost::logging::logger_format_write< > log_type; BOOST_DEFINE_LOG(g_l, log_type) BOOST_DEFINE_LOG_FILTER(g_l_filter, boost::logging::level::holder) #define LAPP_ BOOST_LOG_USE_LOG_IF_LEVEL(g_l(), g_l_filter(), info ) int main( void ) { g_l()->writer().add_destination( destination::cout() ); g_l()->writer().add_destination( destination::syslog_no_levels() ); LAPP_ << "hi"; } when I compile it with "g++ -o syslog_test syslog_test.cpp -I/usr/include/ -lpthread" I get the following errors: /usr/include/boost/logging/format/destination/syslog.hpp:61: error: ‘level’ is not a member of ‘boost::logging::formatter’ /usr/include/boost/logging/format/destination/syslog.hpp:61: error: ‘level’ is not a member of ‘boost::logging::formatter’ /usr/include/boost/logging/format/destination/syslog.hpp:61: error: template argument 1 is invalid A quick look in boost/logging/format/formatter/tags.hpp and I see a typedef for level but no actual definition. If I change line 61 from: struct syslog : is_generic, formatter::uses_tag< formatter::level, ::boost::logging::tag::level >, boost::logging::op_equal::always_equal { to: struct syslog : is_generic, formatter::uses_tag< boost::logging::tag::level, ::boost::logging::tag::level >, boost::logging::op_equal::always_equal { It compiles and appears to work fine (I don't claim to understand the effects of this change). Forgive me if I'm missing something obvious or wasting anyones time. I'm thinking this is a bug but there's a high percentage chance it's an error on my part lol. Anyway, I'm having some great fun with boost (asio and logging so far) and appreciate the work some of you guys have put into these libs. Thanks, Brad

3 4