January 2010 - Boost-users - lists.preview.boost.org

Problems with boost serialization/shared_ptr/container
by Guo, Yanchao 22 Jan '10

22 Jan '10

Hi I am using boost/1.41.0, and the following code give me compilation error when I try to deserialize a shared_ptr. The serialize part it compiled successfully. Can someone advise me if this is a bug in my code or a general issue for boost? Thanks. Yanchao #include <iomanip> #include <iostream> #include <cstddef> // NULL #include <fstream> #include <string> #include <list> #include <cstdio> // remove #include <boost/config.hpp> #if defined(BOOST_NO_STDC_NAMESPACE) namespace std{ using ::remove; } #endif #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/tmpdir.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/list.hpp> #include <boost/serialization/map.hpp> #include <boost/shared_ptr.hpp> #include <list> #include <map> #include <string> #include <sstream> class A{ public: A(){} virtual ~A(){} private: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version) { ar & m_data; } int m_data; }; BOOST_SERIALIZATION_SHARED_PTR(A) typedef std::map<std::string, A > MyMap; BOOST_SERIALIZATION_SHARED_PTR(MyMap ) int main (){ boost::shared_ptr<std::map<std::string, A> > test_ptr; std::string data; std::stringstream buffer(data); boost::archive::text_iarchive ia(buffer); boost::archive::text_oarchive oa(buffer); ia >> test_ptr; //compile error oa << test_ptr; //this is ok return 1; } DISCLAIMER: This e-mail message and any attachments are intended solely for the use of the individual or entity to which it is addressed and may contain information that is confidential or legally privileged. If you are not the intended recipient, you are hereby notified that any dissemination, distribution, copying or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately and permanently delete this message and any attachments.

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Q: N00b spinlock
by Moritz Moeller 21 Jan '10

21 Jan '10

I'm new to multi-threaded programming. So I apologize for aksing what is possibly a silly question. Will below code give me the behaviour of what is commonly called a "spinlock"? boost::unique_lock< boost::shared_mutex > guard( mutex, boost::try_to_lock ); if ( !guard.owns_lock() ) { while ( !guard.try_lock() ) { boost::thread::yield(); } } // access data Cheers, Moritz

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boost::thread object initialization. cannot understand.
by rabbitko＠tenbit.pl 21 Jan '10

21 Jan '10

hallo Group Members compilation of following simple program leads to an error: p1.cpp: In function "int main(int, char**)": p1.cpp:18: error: request for member "join" in "f", which is of non-class type "boost::thread(F (*)())" #include <boost/thread.hpp> #include <iostream> struct F { void operator()() { while (true) { std::cout << "hallo" << std::endl; } } }; int main(int argc, char *argv[]) { // boost::thread f = boost::thread(F()); // But with this line // instead, everything // is ok!! boost::thread f(F()); f.join(); return 0 ; } I am running fc12 with: prompt$ g++ --version g++ (GCC) 4.4.2 20091222 (Red Hat 4.4.2-20) Copyright (C) 2009 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. prompt$ rpm -qi boost Name : boost Relocations: (not relocatable) Version : 1.39.0 Vendor: Fedora Project Release : 8.fc12 Build Date: czw, 15 paĹş 2009, 15:15:15 Install Date: sob, 16 sty 2010, 13:38:26 Build Host: x86-3.fedora.phx.redhat.com Group : System Environment/Libraries Source RPM: boost-1.39.0-8.fc12.src.rpm Size : 0 License: Boost Signature : RSA/8, czw, 22 paĹş 2009, 10:57:44, Key ID 9d1cc34857bbccba Packager : Fedora Project URL : http://www.boost.org/ Summary : The Boost C++ Libraries Description : Boost provides free peer-reviewed portable C++ source libraries. The emphasis is on libraries which work well with the C++ Standard Library, in the hopes of establishing "existing practice" for extensions and providing reference implementations so that the Boost libraries are suitable for eventual standardization. (Some of the libraries have already been proposed for inclusion in the C++ Standards Committee's upcoming C++ Standard Library Technical Report.) have you got any explanation for this? Maybe I should learn C++ better? best regards, Michal

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[thread] NULL cleanup routine for thread_specific_pointer
by Jeremiah Willcock 21 Jan '10

21 Jan '10

There was a post in 2008 (http://lists.boost.org/boost-users/2008/05/36589.php) about using a NULL cleanup function for thread_specific_ptr, but no response to the issue. It appears that there is now a special case in the code for thread_specific_ptr to not call NULL cleanup functions; is this official (and thus can be relied upon)? I did not see it mentioned in the documentation. -- Jeremiah Willcock

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A [bimap] getting iterator on bimap second side
by ishay lavi 21 Jan '10

21 Jan '10

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Problem in boost/boost_1_40/libs/serialization/example/demo.cpp
by John Austin 21 Jan '10

21 Jan '10

This is a versioning bug. The first of the following two lines is missing from the example shipped with 1.40: BOOST_CLASS_VERSION(bus_schedule::trip_info, 2) // missing from example // BOOST_CLASS_VERSION(bus_schedule, 2) // not necessary for example to work. When the schedule is recreated, the driver is not copied to the bus_schedule as the field is contained in the nested struct. When I replace the second macro with the first one, the example works.

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Question about the boost::thread_group
by watsonsong 21 Jan '10

21 Jan '10

I want to use thread_group for multi-thread, and maybe using it like this: void thread2(); void thread1(boost::thread_group& tg) { // create an other thread in the thread_group tg.create_thread(thread2); // do some work for(;;) { //... } } void thread2() { // do some work for(;;) { //... } } int main() { boost::thread_group tg; tg.create_thread(boost::bind(thread1, boost::ref(tg))); tg.join_all(); return 0; } I am puzzling about the join_all() function. Whether is it safe to invoke boost::thread_group::create_thread in an other thread and the join_all will wait for all the tow thread? I saw the source code of thread_group. It used a std::list to keep thread objects, and used a shared_mutex for synchronization. It lock on create_thread and shared lock on join_all. Is that mean if it run on "tg.join_all()" in main thread before "tg.create_thread(thread2);" in thread1, the "tg.create_thread(thread2);" will lead to a dead-lock because the "tg.join_all()" wait for thread1 finish, and thread1 wait for "tg.join_all()" finish on "tg.create_thread(thread2);" If it is so, how can I implement such a function? Thank you. -- View this message in context: http://old.nabble.com/Question-about-the-boost%3A%3Athread_group-tp27220440… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] fusion struct adapt macro, construct the struct from a fusion vector
by Hicham Mouline 21 Jan '10

21 Jan '10

----- Original Message ----- From: "Hicham Mouline" <hicham(a)mouline.org> To: <boost-users(a)lists.boost.org> Sent: Tuesday, January 19, 2010 4:22 PM Subject: Re: [Boost-users] fusion struct adapt macro,construct the struct from a fusion vector >> What about: >> >> template <typename Seq> >> params(Seq const& seq, >> typename boost::enable_if< >> fusion::traits::is_sequence<Seq> >> >::type* = NULL); >> >> ? > > Fantastic. > > Here is the code I have (plz see below), but it seems there are issues > with const-ness that I don't understand. Following my previous attempt, replacing the functor applied by foreach to the zipped sequence by: struct assignelt { template <typename T> void operator()( const vector2<const T&, const T&>& seqpairs ) const { typedef vector2<const T&, const T&> pair_t; const_cast<T&>(at_c<0, const pair_t>(seqpairs)) = at_c<1, const pair_t>(seqpairs); } }; works. I can now construct my struct params from an equivalent fusion sequence. This constructor is identical for all my params struct. I have structs params1 to params100 Is there a way to factorise this ctor and not repeat its definition in the 100 struct params? Is this possible with a base struct templated on the derived struct? rds,

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Getting Original Regular Expression Out From sregex (Boost Xpressive)
by Yan Cheng Cheok 21 Jan '10

21 Jan '10

I have the following code. sregex rex = sregex::compile( "(\\w+) (\\w+)!" ); How I can get "(\w+) (\w+)!" out from rex? Thanks and Regards Yan Cheng CHEOK

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[interprocess] shared map of string to string?
by Anthony Foiani 21 Jan '10

21 Jan '10

I'm using boost.interprocess to build a map from string to string that can be shared between multiple processes, with all read/write access protected by a mutex. I'm having a hard time making it work. Here's a cut-down version of the declaration: template < typename KeyType, typename ValueType, typename StoredKeyType = KeyType, typename StoredValueType = ValueType > class SharedMap : private boost::noncopyable { public: SharedMap( const std::string & shmName, const std::size_t shmSize, const std::size_t initBucketCount = 10 ); ~SharedMap(); void setOneValue( const KeyType & key, const ValueType & value ); bool getOneValue( const KeyType & key, ValueType & value ); void clear(); private: typedef std::pair< const StoredKeyType, StoredValueType > StoredPairType; typedef boost::interprocess::managed_shared_memory ShmManagerType; typedef boost::interprocess::allocator< StoredPairType, ShmManagerType::segment_manager > ShmAllocatorType; typedef boost::interprocess::interprocess_mutex ShmMutexType; typedef boost::interprocess::scoped_lock< ShmMutexType > ShmScopedLock; typedef boost::unordered_map< StoredKeyType, StoredValueType, boost::hash< StoredKeyType >, std::equal_to< StoredKeyType >, ShmAllocatorType > ShmMapType; std::string m_sShmName; ShmManagerType m_manager; ShmMutexType * m_pMutex; ShmMapType * m_pMap; }; // end class SharedMap typedef SharedMap< /* KeyType = */ std::string, /* ValueType = */ std::string, /* StoredKeyType = */ boost::interprocess::string, /* StoredValueType = */ boost::interprocess::string > SharedStringMap; And some important bits of the implementation: #define SHARED_MAP( ret_type ) \ template < \ typename KeyType, \ typename ValueType, \ typename StoredKeyType, \ typename StoredValueType \ > \ ret_type \ SharedMap< \ KeyType, \ ValueType, \ StoredKeyType, \ StoredValueType \ > SHARED_MAP()::SharedMap( const std::string & shmName, const std::size_t shmSize, const std::size_t initBucketCount /* = 10 */ ) : m_sShmName( shmName ), m_manager( boost::interprocess::open_or_create, shmName.c_str(), shmSize ), m_pMutex( m_manager.find_or_construct< ShmMutexType >( "mutex" )() ), m_pMap( m_manager.find_or_construct< ShmMapType >( "map" )( initBucketCount, boost::hash< StoredKeyType >(), std::equal_to< StoredKeyType >(), m_manager.get_allocator< StoredPairType >() ) ) { } SHARED_MAP()::~SharedMap() { try { m_pMutex->unlock(); } catch ( ... ) { } } SHARED_MAP( void )::clear() { ShmScopedLock lock( *m_pMutex ); m_pMap->clear(); } It works fine the first time I run the program, but on the second attempt I get a SIGSEGV when I try to clear the map. My test loop is basically: create or find map for each rep clear map insert values done GDB tells me that this error is originating here: Program received signal SIGSEGV, Segmentation fault. __libc_free (mem=0x8143a48) at malloc.c:3709 3709 if (chunk_is_mmapped(p)) /* release mmapped memory. */ (gdb) bt #0 __libc_free (mem=0x8143a48) at malloc.c:3709 #1 0x001efd12 in operator delete (ptr=<value optimized out>) at ../../../../libstdc++-v3/libsupc++/del_op.cc:44 #2 0x08053d49 in __gnu_cxx::new_allocator<char>::deallocate (this=0xb7fa4334, __p=0x8143a48 <Address 0x8143a48 out of bounds>) at /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../../include/c++/4.4.2/ext/new_allocator.h:95 #3 0x0805e677 in boost::interprocess_container::containers_detail::basic_string_base<std::allocator<char> >::deallocate (this=0xb7fa4334, p=0x8143a48 <Address 0x8143a48 out of bounds>, n=24) at /usr/include/boost/interprocess/containers/container/string.hpp:309 #4 0x0805dac2 in boost::interprocess_container::containers_detail::basic_string_base<std::allocator<char> >::deallocate_block (this=0xb7fa4334) at /usr/include/boost/interprocess/containers/container/string.hpp:341 #5 0x0805d167 in boost::interprocess_container::containers_detail::basic_string_base<std::allocator<char> >::~basic_string_base (this=0xb7fa4334, __in_chrg=<value optimized out>) at /usr/include/boost/interprocess/containers/container/string.hpp:119 #6 0x0805bfe7 in {b::ic::string}::~basic_string (this=0xb7fa4334, __in_chrg=<value optimized out>) at /usr/include/boost/interprocess/containers/container/string.hpp:617 #7 0x0805d671 in std::pair<{b::ic::string} const, {b::ic::string} >::~pair (this=0xb7fa4334, __in_chrg=<value optimized out>) at /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../../include/c++/4.4.2/bits/stl_pair.h:68 #8 0x08063636 in boost::unordered_detail::destroy<std::pair<{b::ic::string} const, {b::ic::string} > > (x=0xb7fa4334) at /usr/include/boost/unordered/detail/hash_table.hpp:233 #9 0x08062d55 in boost::unordered_detail::hash_table_data_unique_keys<ip::allocator<std::pair<{b::ic::string} const, {b::ic::string} >, ip::segment_manager<char, ip::rbtree_best_fit<ip::mutex_family, ip::offset_ptr<void>, 0u>, ip::iset_index> > >::allocators::destroy (this=0xb7f9f0d4, ptr=...) at /usr/include/boost/unordered/detail/hash_table_impl.hpp:133 #10 0x080619fc in boost::unordered_detail::hash_table_data_unique_keys<ip::allocator<std::pair<{b::ic::string} const, {b::ic::string} >, ip::segment_manager<char, ip::rbtree_best_fit<ip::mutex_family, ip::offset_ptr<void>, 0u>, ip::iset_index> > >::delete_to_bucket_end (this=0xb7f9f0d4, begin=...) at /usr/include/boost/unordered/detail/hash_table_impl.hpp:832 #11 0x0805fc63 in boost::unordered_detail::hash_table_data_unique_keys<ip::allocator<std::pair<{b::ic::string} const, {b::ic::string} >, ip::segment_manager<char, ip::rbtree_best_fit<ip::mutex_family, ip::offset_ptr<void>, 0u>, ip::iset_index> > >::clear_bucket ( this=0xb7f9f0d4, b=...) at /usr/include/boost/unordered/detail/hash_table_impl.hpp:867 #12 0x0805e2ff in boost::unordered_detail::hash_table_data_unique_keys<ip::allocator<std::pair<{b::ic::string} const, {b::ic::string} >, ip::segment_manager<char, ip::rbtree_best_fit<ip::mutex_family, ip::offset_ptr<void>, 0u>, ip::iset_index> > >::clear ( this=0xb7f9f0d4) at /usr/include/boost/unordered/detail/hash_table_impl.hpp:879 #13 0x0805d918 in boost::unordered_map<{b::ic::string}, {b::ic::string}, boost::hash<{b::ic::string} >, std::equal_to<{b::ic::string} >, ip::allocator<std::pair<{b::ic::string} const, {b::ic::string} >, ip::segment_manager<char, ip::rbtree_best_fit<ip::mutex_family, ip::offset_ptr<void>, 0u>, ip::iset_index> > >::clear (this=0xb7f9f0c4) at /usr/include/boost/unordered/unordered_map.hpp:271 #14 0x0805cdc3 in Tony::SharedMap<{std::string}, {std::string}, {b::ic::string}, {b::ic::string} >::clear (this=0xbffff40c) at SharedMap.cpp:203 #15 0x0804e3e4 in main (argc=1, argv=0xbffff744) at SharedMapTest.cpp:99 I've done the following substitutions: std::basic_string<char, std::char_traits<char>, std::allocator<char> > -> {std::string} boost::interprocess_container::basic_string<char, std::char_traits<char>, std::allocator<char> > -> {b::ic::string} ip:: -> ip:: Interestingly, it looks like the mutex survives program stops and starts just fine: if I try to run my test case a third time, it sits and waits on the mutex (which got locked just before the 'clear' crashed out in the 2nd invocation) Platform is GCC 4.4.2 (fedora rpm 4.4.2-20) with the RPM packages of boost (1.39.0-8). Any hints would be very much appreciated. I can get a full working test case up on the web, but I need to pull out some bits (especially from the test routine) that rely on other parts of my project. Alternately, if anyone knows of a freely-available implementation of this functionality (or, even better, one that stores std::strings directly instead of having to go to/from b::ip::strings, and maybe one that auto-sizes its shared memory pool)... I'd *definitely* like to hear about that. :) Thanks in advance! Regards, Tony

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