September 2008 - Boost-users

[spirit2] Trivial parser crashes
by sm4 18 Nov '08

18 Nov '08

Hello, Playing with spirit-2 (boost 1.36 release) I got the following code to ASSERT when compiled on Visual Studio 2008/SP1. Any ideas what's wrong? ---------------------------------------------------------- #include #include #include #include #include #include #include #include #include using namespace boost::spirit; using namespace boost::spirit::qi; using namespace boost::spirit::ascii; using namespace boost::spirit::arg_names; namespace phoenix = boost::phoenix; using phoenix::at_c; struct key_val { std::string key; std::string value; }; BOOST_FUSION_ADAPT_STRUCT( key_val, (std::string, key) (std::string, value) ) template struct my_grammar : grammar { my_grammar() : my_grammar::base_type(start) { quoted_string %= lexeme['"' >> +(char_ - '"') >> '"']; key %= quoted_string; value %= quoted_string; start = key [at_c<0>(_val) = _1] >> ':' >> value [at_c<1>(_val) = _1] ; } rule key; rule quoted_string; rule value; rule start; }; int main() { typedef std::string::const_iterator citerator; std::string str = "\"x\": \"25\" "; citerator iter = str.begin(); citerator end = str.end(); my_grammar my_parser; key_val kv; phrase_parse(iter, end, my_parser, kv, space); // ASSERTs return 0; } -------------------------------------------------------------------------- thanks -- View this message in context: http://www.nabble.com/-spirit2--Trivial-parser-crashes-tp19624910p19624910.… Sent from the Boost - Users mailing list archive at Nabble.com.

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[boost-users][bind, signal] binding a weak_ptr?
by Igor R 12 Nov '08

12 Nov '08

Hello, When using shared_ptr, we usually take an advantage of weak_ptr to break the "cycles". But sometimes the "forth connection" between the objects is by means of shared_ptr, while the "back connection" is by means of signal-slot connection. Like this: shared_ptr<Class1> o1; shared_ptr<Class2> o2; o1->someSignal_->connect(bind(&Class2::responder, o2)); // besides, o2 has a shared_ptr to o1 I'd like this signal-slot to be "weak", i.e. instead of "bind(&Class2::responder, o2)" I wish it could be "bind(&Class2::responder, weak_ptr(o2))" - which is illegal. Of course, I can define (and connect to the signal) a wrapping functor that would store a weak_ptr to the wrapped object, and would try to lock it in operator(). But probably boost already have some off-the-shelf solution for this issue? Thanks!

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mutex Locks!
by Wesley Khandavalli 29 Oct '08

29 Oct '08

Dear all, i am new to threading. i want to know the following. Given a shared object which is accessed by more than one process, where should we implement the mutex locking? Is it in the shared object or in the critical section of the Processes? If locking is done in process, will it work having different names for the locks in the processes? class A { .......... ........ public: execute() { ......... lock(mutex1) //write data to shared object unlock(mutex1) ......... } }; class B { .......... ........ public: execute() { ......... lock(mutex2) //write data to shared object unlock(mutex2) ......... } }; SharedObject { ........... .......... }; -- Wesley K

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[test] testing protected/private methods out of test suits
by M. Siebeneicher 27 Oct '08

27 Oct '08

Hello boost-users, I tried to test protected/private class methods by declaring the test-case-class as a friend of the class-to-test. The test-case-class is defined by the macro BOOST_FIXTURE_TEST_CASE(T, F). That works fine as long as I encapsulate the test-case with BOOST_AUTO_TEST_SUITE(suite_name) and BOOST_AUTO_TEST_SUITE_END(). I'm not able to define the correct friend declaration, cause the compiler . Can someone give me hint, please? the code looks like this: // test-case-class.cpp namespace foo { namespace bar { BOOST_AUTO_TEST_SUITE(suite_name) struct F { class-to-test class_to_test_instance; } . . . BOOST_FIXTURE_TEST_CASE(test-case-class, F) { F.class_to_test_instance.i; . . . } . . . BOOST_AUTO_TEST_SUITE_END() }} class-to-test.cpp namespace foo { namespace bar { . . . class class-to-test { public: friend struct test-case-class; // that's wrong // No access to protected member i friend struct suite_name::test-case-class; // this is wrong, too: compiler error, can't find foo::bar::suite_name, .... protected: int i; . . . }; }} greetz, modbom -- GMX startet ShortView.de. Hier findest Du Leute mit Deinen Interessen! Jetzt dabei sein: http://www.shortview.de/wasistshortview.php?mc=sv_ext_mf@gmx

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XML optional field
by Emanuele Rocci 23 Oct '08

23 Oct '08

Hi AllI would like to build a configuration file for my application in XML.The Configuration files includes also optional sectionsi.e. there might be properties that are not required to be defined by the user. If I use BOOST serialization to load this file, the XML format seems to me that forces every field of the XML field to be REQUIRED. Do you know if with Boost serialization for XML there is some mechanismallowing or handling optional Xml field? Kind RegardsManu _________________________________________________________________ Tutto il mondo MSN a portata di clic! http://toolbar.msn.com/overview.aspx?loc=it-it

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serialization 1.36.0 extended_type_info exit issue(s)
by Tim St. Clair 13 Oct '08

13 Oct '08

Folks, I'm running some serialization unit-tests which pass with flying colors under 1.35.0 and earlier, however they seg-fault on exit when run through 1.36.0. The error appears to deal with destruction of extended_type_info_typeid objects, and *only* manifests itself when I load an archive through a shared_ptr<T>. The load will appear to function properly, then on exit of the application, <<Death>>. This occurs even if I remove BOOST_CLASS_EXPORT && BOOST_CLASS_TYPE_INFO as the shared_ptr is to the derived element, and I'm not testing through a base. My lastest guess is that I may be missing some #define BOOST_SOME_MAGIC_NEW_OPTION //////////////////////////// pseduo code: //////////////////////////// BOOST_AUTO_TEST_CASE( MyTestClass_Serialization ) { boost::shared_ptr<MyTestClass> outtie ( new MyTestClass() ); boost::shared_ptr<MyTestClass> innie; std::ofstream os( "MyTestClass_Serialization.xml", std::ios_base::out ); my_pack< MyTestClass >( os, outtie ); os.close(); std::ifstream is( "MyTestClass_Serialization.xml", std::ios_base::in ); my_unpack< MyTestClass >( is, innie ); is.close(); BOOST_CHECK_NO_THROW(); } //////////////////////////// ddd output: //////////////////////////// *** No errors detected [New Thread 0xb73e26c0 (LWP 4715)] Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0xb73e26c0 (LWP 4715)] 0xb76bb56b in std::_Rb_tree_rebalance_for_erase () from /usr/lib/libstdc++.so.6 (gdb) bt #0 0xb76bb56b in std::_Rb_tree_rebalance_for_erase () from /usr/lib/libstdc++.so.6 #1 0xb7a38221 in std::_Rb_tree<boost::serialization::detail::extended_type_info_typeid_0 const*, boost::serialization::detail::extended_type_info_typeid_0 const*, std::_Identity<boost::serialization::detail::extended_type_info_typeid_0 const*>, boost::serialization::detail::type_compare, std::allocator<boost::serialization::detail::extended_type_info_typeid_0 const*> >::erase (this=0xb7a93c94, __position={_M_node = 0x810a3f8}) at /usr/include/c++/4.2/bits/stl_tree.h:1261 #2 0xb7a38270 in std::multiset<boost::serialization::detail::extended_type_info_typeid_0 const*, boost::serialization::detail::type_compare, std::allocator<boost::serialization::detail::extended_type_info_typeid_0 const*> >::erase (this=0xb7a93c94, __position={_M_node = 0x810a3f8}) at /usr/include/c++/4.2/bits/stl_multiset.h:346 #3 0xb7a37482 in boost::serialization::detail::extended_type_info_typeid_0::type_unregister (this=0x810749c) at /opt/tomodev/env/boost/libs/serialization/src/extended_type_info_typeid.cpp:93 #4 0x080b001a in ~extended_type_info_typeid (this=0x810749c) at /opt/tomodev/env/boost/boost/serialization/extended_type_info_typeid.hpp:80 #5 0x0809ebe2 in __tcf_49 () at /opt/tomodev/env/boost/boost/serialization/singleton.hpp:104 #6 0xb74f7084 in exit () from /lib/tls/i686/cmov/libc.so.6 #7 0xb74df458 in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6 #8 0x0809e691 in _start () Cheers, Timothy St. Clair [timothysc(a)gmail.com]

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Visual C++ 2003 and Boost 1.35
by Tomek Jerzykowski 13 Oct '08

13 Oct '08

Hello! I'm having a problem with using Boost 1.35 on Visual C++ 2003 SP1. Take a look at the following very simple program: ------------------------------------ #include "stdafx.h" #include <boost/interprocess/sync/interprocess_upgradable_mutex.hpp> int _tmain(int argc, _TCHAR* argv[]) { int i = 0; unsigned int j = 2; j < i; return 0; } ------------------------------------ It does nothing, just emits a compiler warning. Unfortunately, this warning is followed by lots of meaningless messages related to the included Boost header: ------------------------------------ BoostTest2.cpp c:\BoostTest2\BoostTest2.cpp(11) : warning C4018: '<' : signed/unsigned mismatch c:\Program Files\boost\boost_1_35_0\boost\interprocess\sync\interprocess_upgradable_mut ex.hpp(621) : see reference to class template instantiation 'boost::interprocess::upgradable_lock<M>' being compiled with [ M=boost::interprocess::interprocess_mutex ] c:\Program Files\boost\boost_1_35_0\boost\interprocess\sync\interprocess_upgradable_mut ex.hpp(621) : see reference to class template instantiation 'boost::interprocess::upgradable_lock<M>' being compiled with [ M=boost::interprocess::interprocess_mutex ] ------------------------------------ If I remove #include <boost..., the extra messages go away. It looks to me like compiler bug. The exe produced is probably ok, but the amount of spam in output window makes using Boost very cumbersome. Is there any way to make these messages go away?

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boost::program_options
by Duy Nguyen 09 Oct '08

09 Oct '08

When I try to use the boost::program_options library to read a property file, I got the error when I run "make" on Cygwin (I installed Cygwin on WIndows XP). > make g++.exe -I /cygdrive/c/MyTest/Test1/include/boost-1_34_1/ -c TestInit.cpp Test.cpp TestDriver.cpp g++.exe -I /cygdrive/c/MyTest/Test1/include/boost-1_34_1/ -c TestInit.cpp Test.cpp TestDriver.cpp g++.exe -I /cygdrive/c/MyTest/Test1/include/boost-1_34_1/ -c TestInit.cpp Test.cpp TestDriver.cpp g++.exe TestInit.o Test.o TestDriver.o -o "TestDriver" -L/cygdrive/c/MyTest/Test1/lib -lboost_program_options-gcc34-mt-d-1_34_1 -lg2c Info: resolving vtable for boost::program_options::variables_mapby linking to __imp___ZTVN5boost15program_options13variables_mapE (auto-import) Then when I run my program, it does not work. If I comment out the "try ... catch" block which uses the boost::propram_options library then it compiles and works fine. Please show me how to fix it. Thank you.

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[filesystem] Problem mixing read and write on io fstream
by Sachin Garg 08 Oct '08

08 Oct '08

I have a program which opens a boost fstream in binary input+output mode, creating the file if it doesn't exists. But writing doesn't works after reading, it must be something obvious that I am not aware of. filename is a wpath. f.open(filename,ios::in | ios::out | ios::binary | ios::trunc) The program flow is 1) write some data 2) read the data 3) overwrite old data //this fails I am aware that mixing reading and writting is complicated due to buffering and as far as I know the solution is to do a seekg or seekp when changing between reading and writting, I am doing this between 1, 2 and 3. In 'my' program, writting in step 3 fails. I wrote a simple program that does just the above 3 steps with seeks and it works but in my program, it sets the failbit. After lots of debugging in internal fstream code I figured that an internal flag _IOREAD gets set somehow in step 2 which indicates that the stream is now readonly and causes subsequent writes to fail. It also seems that _IOREAD is set anytime any read operation is done on a read+write file, is this correct? And now how do I 'unset' this flag? I tried calling f.clear and f.seekp but that doesnt helps. What might be special in my program that causes this read-mode flag to remain set while this doesn't happens in a barebone/simple test program. I am not doing anything except f.seekg, f.get, f.read. Sachin Garg ps. If it matters, I am using visual studio 9.0. Problem might not be boost specific as boost only uses stl fstream but any help will be really useful.

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Re: [Boost-users] [statechart] handling unexpected events
by Robert Mecklenburg 05 Oct '08

05 Oct '08

On 2008-09-18 20:54:11 GMT, Robert wrote: > The only thing I can see is that the unconsumed_event() function is > called with the unexpected event object. What I'd like to do in this > function is: > > 1. Abort my transaction and force the state machine back to the Ready > state. I'm not sure how to do this. I've implemented a hack with an internal event, ResetEvent, that I post. This sort of works, but it executes the exit() member function of the aborted state. I'd rather not, I'm trying to abort the behavior of the current state, not complete it. If there was a way from unconsumed_event() to get the current state object and set a flag in it, I could avoid completing the state behavior with a guard. I can use state_downcast<const T *>() to get a const pointer to my state object, but because it is const I can't set a flag. I cannot seem to get a non-const pointer. > 2. Reprocess the unexpected event if it is a hello or get, discard it > otherwise. I'm not sure how to do this, either. I've discovered that post_event() will enqueue any event for processing after the current react() is finished. Thanks for any insight you can provide, -- Robert

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