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Preprocessor problems
by Robert Dailey 11 Aug '08

11 Aug '08

Hi, I'm using Boost.Preprocessor to create specializations of a class I have named InputSource. in the iteration loop, I have the following: # define i BOOST_PP_ITERATION() # define INPUT_repeat(z, n, user) user template<typename t_return, BOOST_PP_ENUM_PARAMS(i, typename t_param)> class InputSource< t_return, BOOST_PP_ENUM_PARAMS(i, t_param) BOOST_PP_COMMA_IF( BOOST_PP_AND(BOOST_PP_NOT_EQUAL(i, 0), BOOST_PP_NOT_EQUAL(i, MAX_PARAMETERS)) ) BOOST_PP_ENUM(BOOST_PP_SUB(MAX_PARAMETERS, i), INPUT_repeat, detail::no_param) > The part that isn't working is the BOOST_PP_COMMA_IF line. When I look at the preprocessor output generated by MSVC9, I get this: template<typename t_return, typename t_param0> class InputSource< t_return, t_param0 BOOST_PP_IIF_BOOST_PP_BOOL_BOOST_PP_BITAND_BOOST_PP_BOOL_BOOST_PP_NOT_EQUAL(1, 0)BOOST_PP_BOOL_BOOST_PP_NOT_EQUAL(1, 5)(BOOST_PP_COMMA, BOOST_PP_EMPTY)() detail::no_param , detail::no_param , detail::no_param , detail::no_param > My iteration limits has been defined as follows: # ifndef MAX_PARAMETERS # define MAX_PARAMETERS 5 # endif # define BOOST_PP_ITERATION_LIMITS (1, MAX_PARAMETERS) I would have expected the preprocessor to show a comma or a blank line, but instead it looks like some macros were not expanded. Any solutions to this problem?

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Concept check vs enable_if
by joel falcou 11 Aug '08

11 Aug '08

Considering the scope of these two libraries, I still wonder which one to use in some cases. For example, let's say I have a set of functions that can only take integers as parameters, what's the correct practice : use enable_if to have SFINAE makes the compiler outputs something like "no such fonction" or have a concept check for Integer and have a concept related error indicating people what happens. Is there any policies or is this a matter of tastes ?

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Re: [Boost-users] weak_ptr for intrusive_ptr
by Alan M. Carroll 11 Aug '08

11 Aug '08

At 09:00 PM 8/10/2008, you wrote: >On Sun, Aug 10, 2008 at 9:47 AM, Alan M. Carroll ><amc(a)network-geographics.com> wrote: >> I greatly prefer intrusive_ptr to shared_ptr, but one drawback of that is there is no equivalent of weak_ptr. I have started work on a class to do that and my biggest question, honestly, was what to name it. > >Have you considered the allocator support in shared_ptr? It makes it >possible to allocate the control block in the same memory block as the >managed object. Between this and the aliasing support in shared_ptr, >I've found intrusive_ptr's use rather limited. I haven't really consider the shared_ptr allocator support. I use primarily intrusive_ptr for historical and implementation reasons. I started using intrusive pointers over a decade ago (my own version at first, later Boost, when it became available). Back then shared_ptr had a much poorer and less usable interface (IIRC, it didn't support casting very well which was a big thing for me). I have long since built support classes to make use of intrusive_ptr very simple, just a 1 line inherit, plus the personal familiarity. Asking why I don't use shared_ptr and its allocator support is effectively asking "why don't you got to a lot of effort to get the same functionality you have now?". Not to disparage shared_ptr, but that's just not an attractive option for me. I might view it differently if I were a newbie, but I'm not, so there it is. Implementing my own intrusive_weak_ptr was less work overall *for me* than switching to shared_ptr. Moreover, shared_ptr doesn't solve the issue that is most important to me, safe conversion to and from raw pointers. This shows up in a couple of places 1) Self registration. 2) Handle from this. 3) Some other very esoteric places that I haven't the energy to go in to and no one else would find interesting. Yes, there are work arounds for shared_ptr, but why not just solve it up front with intrusive_ptr? If, as the flip side of me, you use shared_ptr everywhere else and this doesn't come up much, sure. But my situation is the other way around. Boost takes the right approach, in that it adapts to the peculiarities of the client, it doesn't force the client to adapt to Boost's peculiarities.

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[boost:regex]does boost:regex support char set substraction?
by gj_uestc 11 Aug '08

11 Aug '08

Hi all, I got another problem here while trying using boost:regex: does boost:regex support char set substraction? For example:I give boost:regex an expression"[a-z]-[d-f]".I would like the boost take the second "-" as and substracion. So this expression is supposed to be translated as "[a-c]|[f-z]".I am wonderring whether boost:regex has such substraction symbols? Thanks && Regards Juan

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[python|1.36_beta] Why am I forced to define BOOST_PYTHON_STATIC_LIB?
by Markus Werle 11 Aug '08

11 Aug '08

Hi! I am using VS2005SP1, compiling debug version with MFC in a static lib. No problem for boost libs to auto-select the correct (static) libraries all the time. Enters Boost.Python which deliberately chooses to ignore my compiler settings and to set BOOST_PYTHON_DYNAMIC_LIB and then later at boost\python\detail\config.hpp, line 128: #ifdef BOOST_PYTHON_DYNAMIC_LIB # define BOOST_DYN_LINK // <---- BOOM! #endif which obviously is properly catched in auto_link.hpp, line 292 Everything works as expected if I define BOOST_PYTHON_STATIC_LIB, but I do not understand why I have to take that extra effort. All other boost libs play together with my the compiler settings ... Am I missing something? Markus

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[Boost.asio] Second multicast async_send_to returns 10009
by John Urberg 11 Aug '08

11 Aug '08

I'm using boost asio to send out multicast hailing messages every 15 seconds from an ActiveX control using boost 1.35.0 and VC9. I had a proof of concept ActiveX working fine, but in my production ActiveX, I'm able to send the first message successfully, but every subsequent message returns a 10009 error. Here is the code: MulticastServer::MulticastServer( boost::asio::io_service& io_service, string addr, int port, int seconds) : endpoint(boost::asio::ip::address::from_string(addr), port) , socket(io_service, endpoint.protocol()) , timer(io_service) , server_port(server_port) , seconds(seconds) { socket.set_option(boost::asio::ip::multicast::hops(32)); } void MulticastServer::HandleTimeout(const boost::system::error_code& error) { string message = BuildHailMessage(); std::strcpy(buffer, message.c_str()); socket.async_send_to( boost::asio::buffer(buffer, message.length()), endpoint, boost::bind( &MulticastServer::HandleSendTo, this, boost::asio::placeholders::error)); } void MulticastServer::HandleSendTo(const boost::system::error_code& error) { timer.expires_from_now(boost::posix_time::seconds(seconds)); timer.async_wait(boost::bind(&MulticastServer::HandleTimeout, this, boost::asio::placeholders::error)); } Any ideas what would cause this error message? Also, if I use a string instead of char[] for the buffer, I always receive a 'string iterator not dereferencable' assertion failure. How could I fix that so I can use std::string instead of a char[] buffer? Thanks, John

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Newbie
by Craig Petty 11 Aug '08

11 Aug '08

What headers are the sockets in boost?Hope someone i can help me.:) Craig

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[python] a lot of hassle getting started with embedding and vc8
by Markus Werle 11 Aug '08

11 Aug '08

Hi folks! Probably someone with some hints on how to fix this. I may have overlooked portions of the doc ... Status: boost_1_36_beta installed using bjam for vc8/SP1 against python-2.5.2; python test suite shows no failure. Trying to embed boost::python/Python in a Visual Studio 2008 project: I managed to compile some code in debug mode (linking to python25.lib release mode). The embedded python interpreter (using the precompiled version of python-2.5.2) throws an exception even on statements like "a=2", having "error_already_set", but PyErr_Print(); does not show a message, neither in Debugger nor after calling the executable from the command line. This is odd. So it is time for a debug session - which is where true trouble begins: fetch python source code, compile with vc8 in order to create python25_d.lib and friends. Now what I really want is a *debug* executable with *statically* linked python and boost_python, so I tell it to the boost library by defining BOOST_DEBUG_PYTHON and BOOST_PYTHON_STATIC_LIB. Defining BOOST_PYTHON_STATIC_LIB is necessary to have auto linker link to the static boost_python libs (libboost_python-vc80-mt-sgd.lib) [see http://thread.gmane.org/gmane.comp.lib.boost.user/38461/focus=38600] but has a nasty side effect: Now the compiler decides python_25.lib has to be linked to rather than python25_w.lib. OUCH! I digged into all headers (also using find/grep) to figure out why boost::python now thinks that python25.lib has to be linked into the executable, but could not find the autolinker part for python*.lib. The key part is in boost/python/detail/config.hpp, line 68 // backwards compatibility: #ifdef BOOST_PYTHON_STATIC_LIB # define BOOST_PYTHON_STATIC_LINK # elif !defined(BOOST_PYTHON_DYNAMIC_LIB) # define BOOST_PYTHON_DYNAMIC_LIB #endif I feel uncomfortable about the "backwards compatibility" tag in the comment. So there must be some other way to get around this mess. It all comes down to hinder BOOST_PYTHON_DYNAMIC_LIB to be defined. Looking at [BINARY_DIST]python-2.5.2\include\pyconfig.h - a hand-written version of the python config stuff, there might be some issue with with the "pragma comment(lib" portion ... ================================================== OK, let us revert to dynamic linking then: Using the code from example/quickstart/embedding.cpp I get a <cite> Unhandled exception at 0x00000000 in TestBoostPythonEmbedding.exe: 0xC0000005: Access violation reading location 0x00000000. </cite> triggered by python::object main = python::import("__main__"); calling (*) python::handle<> module(PyImport_ImportModule(n)); // BOOM! but calling PyImport_ImportModule("__main__"); directly succeeds. but stepping into PyImport_ImportModule(n) fails. What's wrong with (*) ? The same game runs without error (!!!!) in release mode. To be honest: I am lost. Any help or hint appreciated. Markus

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[boost.regex]Does boost:u32regex recognize the unicode named blocks like "\p{IsBasicLatin}"?
by gj_uestc 11 Aug '08

11 Aug '08

Hi,all Nowadays I am using boost:u32regex to do some regular expression processing.But it seems that "/p{IsBasicLatin}"is not a accessable expression by boost::make_u32regex(tmp).Does boost:regex not suppor the named unicode blocks or I have to pass some other flags to the library? Now I was using the defult flag wich indicate using perl syntactic. thanks&regards Juan

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[ANN] Boost.Proto committed to trunk
by Eric Niebler 11 Aug '08

11 Aug '08

I've just committed Boost.Proto v4 to trunk (http://svn.boost.org/trac/boost/changeset/48079) This version is represents a significant reworking from the version that was reviewed and accepted back in April. Although the code is quite stable now, I have not yet integrated all the feedback about the documentation. It is my intention to bring the docs up to Boost standards in time to get Proto into 1.37. I am leaving the old version of Proto at boost/xpressive/proto for the time being, since some other projects (Xpressive, Spirit2 Qi and Karma) are relying on it. It will be removed at the earliest opportunity. I've also updated the proto.zip archive in the Boost file vault and uploaded the latest docs to: http://boost-sandbox.sourceforge.net/libs/proto/doc/html/index.html Thanks, -- Eric Niebler BoostPro Computing http://www.boostpro.com

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