- Boost-users - lists.boost.org

bjam upgrade issue
by Joe Angell 12 Jun '07

12 Jun '07

Hello, After upgrading bjam from version 03.01.11 to 03.1.13 I ran into an issue that is not backwards compatible, and I am wondering if someone has an alternative solution. actions svn_export { svn export $(>) $(<) } make $(TOP)/oak/test/out/SMALL/ : $(TOP)/test/xylem_test_data/SMALL/ : svn_export ; This make rule no longer works in the 3.1.13 version upon directories as targets (works fine for file targets). Any suggestions? Thanks, -- --------------- Joe Angell Boulder Labs, Inc. 7105 LaVista Pl Suite 200 Niwot, CO 80503 (303) 817-8252

1 0

Newbie Boost::Graph - How to write to a .dot file
by Erica Calogero 12 Jun '07

12 Jun '07

Hi there, I am having difficulty writing to a .dot file. After typing in the follwoing code (following the example in the book, p.85). write_graphviz("ECgraphs/test_network.dot",angle_list); I get the following error message: Error 89 error C2664: 'boost::write_graphviz' : cannot convert parameter 1 from 'const char [26]' to 'std::ostream &' What code do I have to write to convert my 'const char [26]' to a 'std::ostream &'? Thanks, Kind regards, Erica.

2 1

MPL intersection of type sequences and compile-time performance
by Andrej van der Zee 12 Jun '07

12 Jun '07

Hi, Sorry if this already has been posted, but I have a problem with compile-time performance when trying to get the intersection of two type sequences. For example, when I do something like this: template<typename list1, typename list2> struct intersect { typedef typename boost::mpl::remove_if<list1, mpl::not_< mpl::contains<list2, mpl::_1> >::type type; }; typedef mpl::vector<a,b,...,z> l1; typedef mpl::vector<c,e,t,u,v> l2; typename intersect<list1,list2>::type my_intersection; Then for large type sequences compile-time becomes unacceptable (O(M*N)). Is there a better way to do this? Thanks, Andrej ___________________________________________________________ To help you stay safe and secure online, we've developed the all new Yahoo! Security Centre. http://uk.security.yahoo.com

3 4

[boost::filesystem::path] does it work on windows?? please
by jono 12 Jun '07

12 Jun '07

i won't even include my code. anyone?

3 2

How can i kill boost::thread?
by Meryl Silverburgh 12 Jun '07

12 Jun '07

Hi, If I create a thread using boost::thread() library? boost::thread thrd( &DoWork ) ); How can I kill "thrd" later on? Thank you.

4 4

Performing static_cast<shared_ptr<base>*> on a shared_ptr<derived>*. Any guarantees?
by Pete Bartlett 11 Jun '07

11 Jun '07

I have taken over some code that boils down to ///begin code #include <iostream> #include <boost/shared_ptr.hpp> struct base { int i; base(int i_):i(i_) {} }; struct derived : base { derived(int i): base(i) {} }; int main() { boost::shared_ptr<derived> pd(new derived(5)); void* ptr_to_pd = &pd; boost::shared_ptr<base>* ptr_to_pb = static_cast< boost::shared_ptr<base>* >(ptr_to_pd); std::cout << "\n" << (**ptr_to_pb).i ; //Prints 5 } ///End code Now shared_ptr<B> and shared_ptr<A> are unrelated types, so IIUC there is no guarantee that this will work. Is that right? I know from the shared_ptr documentation that I should refactor in the direction of dynamic_ptr_cast (though complications not shown in the code above make that harder that). However for the time being this code appears to be working. Is that just a fluke? I.e. I am relying on the author of boost::shared_ptr and/or my compiler creators not to do something such that it doesn't work. Is there the possibility that any memory could be deleted twice? Or I am worrying over nothing and in fact there is a reason why the above is safe? Many thanks for any advice you can provide, Peter Bartlett

3 2

[bind] Help with functional composition of shared_ptr::use_count in std::map
by Hughes, James 11 Jun '07

11 Jun '07

Hello all, I'm trying to use bind to help with removeif in a std::map<string, shared_ptr<something> >. I want to remove items where the shared_ptr use_count is 1. map<string, shared_ptr<data> > Fred; RemoveIf(Fred.begin(), Fred.end(), boost::bind(std::equal_to<long>(), 1, boost::bind(&map<string, shared_ptr<data> >::value_type::second::use_count, _1) ) However, I get a compile error on ::second not being a class or namespace. Anyone know how I should do this? I'm a beginner at boost::bind, so be gentle.... James This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.

2 4

Re: [Boost-users] [bind] Help with functional compositionofshared_ptr::use_count in std::map
by Küppers, Ben 11 Jun '07

11 Jun '07

> map<string, shared_ptr<data> > Fred; > > RemoveIf(Fred.begin(), > Fred.end(), > boost::bind(&map<string, shared_ptr<data> > >::value_type::second::unique, _1) > ) James, remove_if requires an assignment operator on the operated type but the value_type of a map is defined as std::pair< const T1, T2 >. The const on the first type will cause any assignment to fail. In other words, you can't use remove_if on a map. That said, in order to fix your bind you would need two functors. The type passed to the bind is the value_type of the map which is by definition a pair. You need to first invoke a functor on the pair to extract the second member and then call the member unique on the resulting smart pointer. In order to do so you'll need to write your own extractor, because the STL does not provide a functor to obtain the "second" field from a pair (I haven't found one in boost either). template< class Pair > struct second_of : std::unary_function< Pair, typename Pair:second_type > { typename Pair::second_type opertator()( const Pair& the_pair ) const { return the_pair.second; } }; std::for_each( Fred.begin(), Fred.end(), boost::bind( boost::shared_ptr< data >::unique, boost::bind( second_of< std::map< std::string, boost::shared_ptr< data > >::value_type >(), _1 ) ) ); Note that you can call for_each as it does not require the assignment operator. Hope this helps, Ben This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you.

2 1

Problems with boost.thread
by luca regini 11 Jun '07

11 Jun '07

I have some problems with boost.thread (version 1_34) under gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-52). The library ( all the boost distribution) compiles fine and a bjam on the ./libs/thread/test directory also report a successful test execution. However when i try to explicitly link one of the example (tread_group with the boost tread library using the following command line: g++ -I/opt/six/boost_1_33_1 -I/opt/six/boost_1_34/include/boost-1_34 -pthread -o mytest thread_group.cpp libboost_thread-gcc32-mt-d-1_34.so.1.34.0 i get a segmentation fault. >From a core dump i can see the following stacktrace: 0 0x008e78fb in boost::function0<void, std::allocator<boost::function_base> >::assign_to_own (this=0xb75e5420, f=@0xbfffacb0) at ../../../boost/function/function_template.hpp:647 647 f.vtable->manager(f.functor, this->functor, (gdb) backtrace #0 0x008e78fb in boost::function0<void, std::allocator<boost::function_base> >::assign_to_own (this=0xb75e5420, f=@0xbfffacb0) at ../../../boost/function/function_template.hpp:647 #1 0x008e748f in function0 (this=0xb75e5420, f=@0xbfffacb0) at ../../../boost/function/function_template.hpp:527 #2 0x008e6748 in thread_proxy (param=0xbfffac20) at ../../../libs/thread/src/thread.cpp:106 #3 0x0040f371 in start_thread () from /lib/tls/libpthread.so.0 #4 0x001d8ffe in clone () from /lib/tls/libc.so.6 Where is the problem?? Thanks in advance, Luca Regini

2 2

Question about boost mutex
by Meryl Silverburgh 11 Jun '07

11 Jun '07

Hi, I have a application which uses p_thread for creating threads, can i use the boost mutex classes for thread synchronization? Or the boost mutex class only works with boost thread class? Thank you.

2 1