November 2011 - Boost-users

using a boost::shared_mutex in a share_ptr
by Sean Farrow 01 Nov '11

01 Nov '11

Hi: I have the following variable declared in a class: Boost::shared_ptr<boost;:shared_mutex> If I have a standard boost::shared_mutex, I can pass this to a shared or unique lock. How do I pass a boost::shared_ptr<boost::shared_mutex> to a lock? This is probably really simple, but I carn't fathum it out! Cheers Sean.

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serialization of a ptr
by Jonathan Bishop 01 Nov '11

01 Nov '11

How do I prevent boost::serialize from treating a pointer as an object and serializing the object. I have written the specialization of save/load for the object pointer. I get the following errors when I attempt to compile the program below... boost/serialization/access.hpp: In static member function 'static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive, T = X]': boost/serialization/serialization.hpp:81: instantiated from 'void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive, T = X]' boost/serialization/serialization.hpp:140: instantiated from 'void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive, T = X]' boost/archive/detail/oserializer.hpp:151: instantiated from 'void boost::archive::detail::oserializer<Archive, T>::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::binary_oarchive, T = X]' s3.cpp:53: instantiated from here boost/serialization/access.hpp:109: error: 'class X' has no member named 'serialize' ============================================================================================== #include <fstream> #include <sstream> #include <cstddef> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> #include "boost/serialization/split_free.hpp" using namespace std; class X { X(const X& other); X& operator=(const X& other); public : static X* get(int id); X() : id(0) {} int id; }; // Non-intrusive serialization (pretend I am not able to modify class X) // I was hoping serialization would use this specialization // archive X by id template<class Archive> void save(Archive& ar, X*& x, unsigned int version) { int id = x->id; ar & id; } // load X by lookup template<class Archive, class T> void load(Archive& ar, X*& x, unsigned int version) { int id; ar & id; x = X::get(id); } template<class Archive, class T> inline void serialize(Archive& ar, X*& t, const unsigned int version) { split_free(ar, t, version); } int main() { X x; std::ofstream ofs("junk"); boost::archive::binary_oarchive oa(ofs); oa & x; ofs.close(); return 0; }

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[test] boost.test bug report email address?
by legalize+jeeves＠mail.xmission.com 31 Oct '11

31 Oct '11

[Please do not mail me a copy of your followup] The docs say I can report a bug to the email address <boost-test =at= emailaccount =dot= com> but this is undeliverable for 7 days. -- "The Direct3D Graphics Pipeline" -- DirectX 9 version available for download <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/> Legalize Adulthood! <http://legalizeadulthood.wordpress.com>

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Common parameter on command line and in a config file with sections
by Gruhn, Dan 31 Oct '11

31 Oct '11

Greetings, I would like to have a parameter "expire-days" that has a default and can be set via the command line --expire-days|-e <days> and a config file [foo] expire-days = <days> It would be most elegant to be able to specify things like this (notice the automatic storage to the expireDays variable): namespace bpo = boost::program_options; int expireDays = 30; bpo::options_description desc("Allowed options"); desc.add_options() ("expire-days,e", bpo::value<int>(&expireDays)->default_value(expireDays), "Number of days before files expire") ; bpo::options_description configFileDesc; configFileDesc.add_options() ("foo.expire-days", bpo::value<int>(&expireDays), "") ; bpo::variables_map varMap; try { // Attempt to parse the configuration file. std::ifstream cfg("/tmp/all.cfg"); if (cfg.is_open()) { std::cout << "Opened /tmp/all.cfg" << std::endl; static const bool allowUnregistered = true; bpo::store(bpo::parse_config_file(cfg , configFileDesc, allowUnregistered), varMap); } // Parse the command line bpo::store(bpo::parse_command_line(argc, argv, desc), varMap); bpo::notify(varMap); } std::cout << "Expire days: " << expireDays << std::endl; My code may be strange but I am trying to find the right order and combination of adding options, parsing, storing, and notifying that gives the command line priority over the config file which in turn has priority over the 30 day default. Oddly enough, it doesn't seem to make much difference which order I use, the config file seems to have precedence This is not what I expected so perhaps I'm doing something wrong but I can't find it. I know that I can accomplish this via extra code on my part, but I'm trying to come up with a general scheme that would work for multiple programs with multiple variables using a common config file and the simpler the better. The documentation mentions using sections in config files but doesn't give much detail. Can anyone help me here or at least describe for me which of add_options, parse_*, store, and notify does the following: 1) Sets the default value 2) Marks that a value has been set from the command line/config file. 3) Actually does the store to the given variable. 4) What does notify do? I've tried (and continue to try) looking through the code but am having problems find the right place examine. I'll take pointers in that area as well. This does not seem like an exotic use case. Has anyone else accomplished this or something like it? As always, any help of any kind will be greatly appreciated. Dan

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