- Boost - lists.boost.org

Question for C++ experts about exception allocation failure
by Emil Dotchevski 20 May '09

20 May '09

How is failure to allocate an exception object handled in various compilers? 15.1.4 says that "the memory for the temporary copy of the exception being thrown is allocated in an unspecified way" but I don't think it specifies behavior for the case when the allocation fails. I know that some compilers allocate exceptions from the heap, so does this mean that an attempt to throw any exception could, in theory, result in a std::bad_alloc being thrown instead? As far as I can tell such behavior wouldn't violate the C++ standard, but I'm not sure my interpretation is correct. Anyone? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

9 17

[MPL] Is there an "include all" header?
by Adam Badura 20 May '09

20 May '09

I am looking for a "include all" header for Boost.MPL. Is there such? For the Boost.Preprocessor (having similar structure) there is <boost/preprocessor.hpp> however <boost/mpl.hpp> does not exist. Is it by purpose or just a forgotten feature? Actually I think having such "include all" headers is very convenient especially for larger libraries. (Yes, I know I can write such header by myself and then just use it every time I want to use Boost.MPL however having a "standard one" would be easier I think.) Adam Badura

1 0

Volunteering to be a Review Manager
by Stewart, Robert 20 May '09

20 May '09

One thing that http://www.boost.org/community/reviews.html#Review_Manager doesn't mention is how a prospective review manager should volunteer. Presumably, one just sends a message to the developer's list to that effect, but I'd think a prescribed subject line would increase the likelihood that the review wizard sees it. _____ Rob Stewart robert.stewart(a)sig.com Software Engineer, Core Software using std::disclaimer; Susquehanna International Group, LLP http://www.sig.com IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

2 1

Re: [boost] Interest check: container with preallocated buffer
by Brian Wood 19 May '09

19 May '09

Thorsten Ottosen writes: >>Dmitry Vinogradov skrev: >> Boost.Array offers constant size container with preallocated buffer, >> Boost.Optional provides from zero to one element. There are no STL >> container with preallocated buffer and it seems custom allocator does >> not help to do this with existing containers. >> >> Does any container exist to offer functionality like Boost.Array but >> allowing to store from 0 to N elements? Is there any interest in such >> container? >> >> PS. It's similar to fixed_string but as a generic container. >Please see >http://www.cs.aau.dk/~nesotto/boost/auto_buffer.zip >http://www.cs.aau.dk/~nesotto/boost/trunk/libs/auto_buffer/doc/html/ > I was looking at the documentation and the Serialization and "Differences from std::vector<T>" pages were both empty. It would be nice to indicate there's nothing there yet for those pages. On the Semantics page is says: auto_buffer( const auto_buffer& r ); - *Effect:* Copy constructor. - *Postconditions:* capacity() == max(r.size(),N) && size() == r.size() . - *Throws:* Nothing if size() <= N and the copy constructor of T cannot throw. Otherwise this might throw exceptions from the allocator of from T's copy constructor. I think there's a typo in the last sentence there. -- Brian Wood Ebenezer Enterprises www.webEbenezer.net "Then Samuel took a rock and set it up between Mizpah and Shen. He named it Ebenezer [Rock of Help] and said, 'Until now the LORD has helped us.'"

2 1

[array] assignement operator
by vicente.botet 19 May '09

19 May '09

Boost.Array defines an assignement operator with the following prototype template<typename T, std::size_t N> class array { public: /... template<typename U> array& operator=(const array<U, N>& rhs); // Effects:std::copy(rhs.begin(),rhs.end(), begin()) }; I was wondering if this can be extended to manage with arrays of different sizes, having as effect the copying of the minimum of N and M elements from the source to the target. template<typename T, std::size_t N> class array { public: /... template<typename U, std::size_t M> array& operator=(const array<U, M>& rhs); // Effects:std::copy(rhs.begin(),rhs.begin()+min(N,M), begin()) }; Is there anything wrong with this interface? Best, _____________________ Vicente Juan Botet Escribá

5 11

Boost up for SourceForge Community Choice Award
by David Abrahams 19 May '09

19 May '09

Cast your vote here: http://tinyurl.com/boost-cca09 Cheers, -- Dave Abrahams BoostPro Computing http://www.boostpro.com

2 1

[thread] Exception propagation for thread::join
by Emil Dotchevski 18 May '09

18 May '09

When joining a thread, in case the thread has exited, I find it convenient to have any exception the thread function throws propagated to the caller of join(). Just as an illustration of what I'm talking about, below is my Win32 implementation of a similar interface. An interesting design decision is what to do if a detached thread throws an exception. Note the line marked with (1) -- I've decided to assert in this case (instead of ignoring the exception, which would be the alternative behavior.) Would something similar be a good addition to Boost Thread? struct windows_thread_info { DWORD id; boost::shared_ptr<HANDLE const> h; boost::function<void()> f; mutable boost::exception_ptr e; boost::shared_ptr<windows_thread_info> self; ~windows_thread_info() { assert(!e); } }; namespace { DWORD WINAPI thread_proc_fwd( void * p ) { assert(p!=0); boost::weak_ptr<windows_thread_info> w; boost::function<void()> f; { boost::shared_ptr<windows_thread_info> wti; static_cast<windows_thread_info *>(p)->self.swap(wti); assert(wti); f=wti->f; assert(f); w=wti; } try { f(); } catch( ... ) { boost::shared_ptr<windows_thread_info> wti=w.lock(); assert(wti); //(1) wti->e=boost::current_exception(); } return 0; } } boost::shared_ptr<windows_thread_info const> win_CreateThread( LPSECURITY_ATTRIBUTES lpThreadAttributes, SIZE_T dwStackSize, boost::function<void()> const & f, DWORD dwCreationFlags ) { assert(f); boost::shared_ptr<windows_thread_info> wti(new windows_thread_info); wti->f=f; wti->self=wti; if( HANDLE h=CreateThread(lpThreadAttributes,dwStackSize,thread_proc_fwd,wti.get(),dwCreationFlags,&wti->id) ) { make_handle(h,CloseHandle).swap(wti->h); return wti; } else { wti->self.reset(); BOOST_THROW_EXCEPTION(x_system() << xi_win_last_error(GetLastError()) << xi_function("CreateThread")); } } void join( windows_thread_info const & wti ) { (void) win_WaitForSingleObject(*wti.h,INFINITE); boost::exception_ptr e; { using std::swap; swap(e,wti.e); } if( e ) boost::rethrow_exception(e); } -- Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

4 3

git clone up
by troy d. straszheim 18 May '09

18 May '09

In case this reaches any other git enthusiasts, I've rigged up a git clone that is automatically tracking boost svn, here: http://sodium.resophonic.com/git/boost/ Click around on it... it's smoking fast, despite the fact that it is running on hardware I found in the trash on the end of a mediocre uplink. There is a little howto here: http://sodium.resophonic.com/git/boost/about/ The repository (minus checkout) is about 150M, it contains branches and tags going all the way back. It will take a while to do the initial clone but fetches after that are very fast. -t

4 8

release notes for 1.39.0?
by Neal Becker 18 May '09

18 May '09

Where can I find some more detailed release notes? I looked here: http://comments.gmane.org/gmane.comp.lib.boost.announce/233

2 1

[serialization] Enum loading may lead to uninitialized value [Ask for change]
by Andrey Upadyshev 18 May '09

18 May '09

Hi! I found that template boost::archive::detail::load_enum_type (boost\archive\detail\iserializer.hpp) may overvrite loading enum's value with uninitialized ones. See comments: template<class Archive, class T> struct load_enum_type { static void invoke(Archive &ar, T &t){ int i; // Initialize 'i' with trash ar >> boost::serialization::make_nvp(NULL, i); // Imagine: some code in archive skips loading t = static_cast<T>(i); // Ooops, get the trash into 't' } }; I think it is more secure to initialize 'i' from 't'. So, if archive's code skips loading, we just get 't' unchanged instead of corrupted. Probably, someone can fix this in svn? Andrey Upadyshev P.S. Sorry for my English.

2 2