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Is there a boost equivalent of eastl::fixed_vector?
by dariomt＠gmail.com 25 Sep '08

25 Sep '08

In EASTL http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2271.htmlthere is something like SSO (Small String Optimization) applied to std::vector (and other STL containers) [begin quote] "Fixed containers are fixed-size containers with their memory stored right within the container itself. Fixed containers allocate no dynamic memory and their memory tends to be cache-friendly due to its contiguity and proximity to the container's housekeeping data. The user declares the max container size as a template parameter, and can also specify that if the container overflows that an auxiliary dynamic allocator is used. template <typename T, size_t nodeCount, bool enableOverflow = true, typename Allocator overflowAllocator = EASTLAllocator> class fixed_vector { ... }; [end quote] I have tried a similar approach using some sort of fixed_buffer_with_overflow allocator, with no success. I'm not sure SSO is even possible just using an allocator with the standard containers, because I always end up with stateful allocators. So my question is if there is something similar already in boost. TIA

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bjam JAMSHELL
by Gerhard Lipp 25 Sep '08

25 Sep '08

hello! i would like to specify a different shell for bjam on windows xp (namely sh.exe). i tried to place JAMSHELL = C:\\Programme\\A-Toolchain\\bin\\sh.exe -c % ; in my Jamroot file, though without success, the windows cmd "shell" gets called. background: i have to invoke a shell script (wx-config) to get my cxxflags like that local wx_cxxflags = [ SHELL "wx-config --cxxflags | tr -d '\\n'" ] ; regards, gerhard

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make check results version 1.36.0
by mess-mate 25 Sep '08

25 Sep '08

Hi, this is what i have after a 'make check' when compiling boost: .../... ...failed updating 13 targets... ...skipped 18 targets... ...updated 19995 targets... Some Boost regression tests failed. This is normal for many compilers. ..../.... Is there any reason to not continue the installation ? best regards

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[logging]Redirecting process output to log
by Vladimir Kiryazev 25 Sep '08

25 Sep '08

Hello, I am using the logging library by John Torjo. I create a process in my program and need to redirect its output to log. How do I do this? Thanks.

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[math] boost build error: ::log1pl has not been declared
by Pfligersdorffer, Christian 24 Sep '08

24 Sep '08

Hello all, cross compiling boost 1.36 for power pc using a gcc-4.0 derivative the math library ends up with the following error: ./boost/math/special_functions/log1p.hpp: In function 'long double boost::math::log1p(long double, const Policy&)': ./boost/math/special_functions/log1p.hpp:342: error: '::log1pl' has not been declared my gcc configuration is: Target: powerpc-linux Configured with: /opt/eldk/build/ppc-2006-01-11/work/usr/src/denx/BUILD/crosstool-0.35/bu ild/gcc-4.0.0-glibc-2.3.5-eldk/powerpc-linux/gcc-4.0.0/configure --target=powerpc-linux --host=i686-host_pc-linux-gnu --prefix=/var/tmp/eldk.BjN6Wo/usr/crosstool/gcc-4.0.0-glibc-2.3.5-eldk/p owerpc-linux --with-headers=/var/tmp/eldk.BjN6Wo/usr/crosstool/gcc-4.0.0-glibc-2.3.5- eldk/powerpc-linux/powerpc-linux/include --with-local-prefix=/var/tmp/eldk.BjN6Wo/usr/crosstool/gcc-4.0.0-glibc-2 .3.5-eldk/powerpc-linux/powerpc-linux --disable-nls --enable-threads=posix --enable-symvers=gnu --enable-__cxa_atexit --enable-languages=c,c++ --enable-shared --enable-c99 --enable-long-long Thread model: posix gcc version 4.0.0 (DENX ELDK 4.0 4.0.0) Does anyone have a solution for this? Regards, -- Christian Pfligersdorffer Dipl.-Ing. Bakk.rer.nat. Software Engineering EOS GmbH - Electro Optical Systems Robert-Stirling-Ring 1 D-82152 Krailling / Munich Phone +49 89 893 36-229 Fax +49 89 893 36-287 christian.pfligersdorffer(a)eos.info http://www.eos.info

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How to test if a type is of some form?
by Peng Yu 24 Sep '08

24 Sep '08

Hi, I want to test if template argument is of some form like in the following code. I could define some helper class to do such test. But I'm wondering if there is any easy to do it with boost? The type_traits's is_same does not work in this case. I'm wondering if there could be some generalization of it. template <T> void f() { //For example, I want to test if T is of the // form of std::complex<S> } Thanks, Peng

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[Thread] Not able to compile a program with Thread library on ARM
by Rudi Dittrich 24 Sep '08

24 Sep '08

Dear all, I've got the following problem: I want to use the boost threading library provided in version 1.36 on an arm (imx31) based evaluation board with MontaVista linux and g++ version 4.2.0 on it. When I try to compile the following example with my arm-g++ compiler #include <vector> #include <boost/shared_ptr.hpp> #include <boost/thread.hpp> #include <boost/bind.hpp> class Worker { private: int _id; ///< The id of the worker. public: Worker( int id ) : _id( id ) {} // Is the function that is called when this worker is started. // Doesn't do anything usefull. void run() { for (unsigned int i=0; i<30000000; i++); } }; typedef boost::shared_ptr<Worker> worker_ptr; typedef std::vector<worker_ptr> worker_vec; // Starts worker threads. void run( int nr_workers ) { worker_vec workers( nr_workers ); boost::thread_group tg; for (int i = 0; i < nr_workers; i++) { worker_ptr w( new Worker(i) ); workers[i] = w; tg.create_thread( boost::bind( &Worker::run, w ) ); } tg.join_all(); } int main( int argc, char *argv[] ) { int worker_nr = 5; run( worker_nr ); return 0; } I get the following error message: /opt/montavista/mobilinux/devkit/arm/v6_vfp_le/lib/gcc/armv6fl-montavista-linux-gnueabi/4.2.0/../../../../armv6fl-montavista-linux-gnueabi/bin/ld: thread-test: hidden symbol `__sync_add_and_fetch_4' in /opt/montavista/mobilinux/devkit/arm/v6_vfp_le/lib/gcc/armv6fl-montavista-linux-gnueabi/4.2.0/libgcc.a(linux-atomic.o) is referenced by DSO /opt/montavista/mobilinux/devkit/arm/v6_vfp_le/lib/gcc/armv6fl-montavista-linux-gnueabi/4.2.0/../../../../armv6fl-montavista-linux-gnueabi/bin/ld: final link failed: Nonrepresentable section on output collect2: ld returned 1 exit status I do not get any linking errors while compiling it on my PC, so may be there is missing something? I've read in "http://lists.boost.org/Archives/boost/2007/09/127103.php " that this problems comes from the fact that __sync__fetch_and_add(&x,1) , which is needed by shared_pointers, is not implemented in gcc for ARM. So according to the problem stated above I've two questions: - Does there already exist a workaround which solves the problem mentioned above? - I have added a new header file (atomic_count_arm.hpp) to the boost/detail directory. It implements the atomic_count class with specific arm inline assemply instructions in the operator overloads functions. #ifndef BOOST_DETAIL_ATOMIC_COUNT_ARM_HPP_INCLUDED #define BOOST_DETAIL_ATOMIC_COUNT_ARM_HPP_INCLUDED namespace boost { namespace detail { class atomic_count { public: explicit atomic_count( long v ) : value_( v ) {} void operator++() { long tmp; int result; __asm__ __volatile__( "1: ldrex %0, [%2]\n" " add %0, %0, #1\n" " strex %1, %0, [%2]\n" " cmp %1, #0\n" " bne 1b" : "=&r"(tmp), "=&r"(result) // output parameters : "r"(&value_) // input parameters : "memory", "cc" // clobbers ); } long operator--() { long tmp; int result; __asm__ __volatile__( "1: ldrex %0, [%2]\n" " add %0, %0, #-1\n" " strex %1, %0, [%2]\n" " cmp %1, #0\n" " bne 1b" : "=&r"(tmp), "=&r"(result) // output parameters : "r"(&value_) // input parameters : "memory", "cc" // clobbers ); } operator long() const { long tmp; int result; __asm__ __volatile__( "1: ldrex %0, [%2]\n" " strex %1, %0, [%2]\n" " cmp %1, #0\n" " bne 1b" : "=&r"(tmp), "=&r"(result) // output parameters : "r"(&value_) // input parameters : "cc" // clobbers ); return tmp; } private: atomic_count(atomic_count const &); atomic_count & operator=(atomic_count const &); mutable long value_; }; } // namespace detail } // namespace boost #endif Further I've added the following lines into atomic_count.hpp: #elif defined( __GNUC__ ) && ( __GNUC__ * 100 + __GNUC_MINOR__ >= 401 ) && defined( __arm__ ) #include <boost/detail/atomic_count_arm.hpp> and before: #elif defined( __GNUC__ ) && ( __GNUC__ * 100 + __GNUC_MINOR__ >= 401 ) # include <boost/detail/atomic_count_sync.hpp> Then I recompiled boost and the threading example given above and suprise, it compiles. I'm also able to execute the test-program. So, do you think that this is feasable solution? Best regards, Rudi Dittrich -- 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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no_std_locale_fail.test when compiling boost 1.36.0
by mess-mate 24 Sep '08

24 Sep '08

Hi folks, i'd like to compile the boost lib 1.36.0. But have over and over this error: **passed** bin.v2/libs/config/test/all/no_std_locale_fail.test/gcc-4.1.3/release/threading-multi/no_std_locale_fail.test How can i solve this ? Any help welcome best regards

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[Range] Adapt 2-iterator container constructors for Range?
by Nat Goodspeed 24 Sep '08

24 Sep '08

As I work with Boost.Range, I frequently want to call a method returning an iterator_range and, from that range, instantiate a standard container. I have a couple of helpers I'd like to propose for inclusion in the Boost.Range library. /** * From any range compatible with Boost.Range, return an instance of any * class with a constructor accepting a compatible iterator pair. */ template<class TYPE, typename RANGE> TYPE make_from_range(const RANGE& range) { return TYPE(boost::begin(range), boost::end(range)); } It would probably be appropriate to provide a non-const RANGE& overload as well. make_from_range<CONTAINER>(range) is helpful for, e.g., passing an argument to a function accepting const CONTAINER&. But what if you want to declare a local instance of such a container? /** * From any range compatible with Boost.Range, instantiate any class * with a constructor accepting a compatible iterator pair. */ template<class TYPE> struct instance_from_range: public TYPE { template<typename RANGE> instance_from_range(const RANGE& range): TYPE(boost::begin(range), boost::end(range)) {} // Again, a non-const RANGE& overload would probably be useful. }; Usage example: instance_from_range< std::vector<std::string> > my_vector(function_returning_range_of_string()); Perhaps instance_from_range might be more controversial because of the recommendation not to subclass standard containers. My thought is that once the (nearly trivial) constructor has executed, we can completely disregard the subclass. I've used it in a context where instance_from_range<CONTAINER> is "sliced" to the CONTAINER itself. Though these are small enough to recreate on demand, they're useful enough that I'd like to have them available everywhere. I hope others might find them helpful too.

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[Filesystem] has_root_path()
by Robert Jones 24 Sep '08

24 Sep '08

Boost 1.33.1 used to support has_root_path() on directory_iterators. 1.36 seems to use a slightly different mechanism for directory_iterators, based on instantiating basic_directory_iterator, and I'm struggling to see what has happened to has_root_path(). It's there somewhere, but not accessible in quite the same way as it was. How do I express directory_iterator -> has_root_path() in 1.36.0 ? Thanks - Rob.

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