February 2005 - Boost - lists.preview.boost.org

BOOST_PP_SEQ_FOR_EACH_I
by Arkadiy Vertleyb 13 Feb '05

13 Feb '05

Hi all, I don't think that reentrancy mechanism is working for this macro. Is it supposed to? The following example illustrates my problem (I tried both automatic and manual methods): #include <boost/preprocessor/seq/for_each_i.hpp> #define seq\ ((1)(2)(3))\ ((4)(5)(6))\ ((7)(8)(9)) #define MACRO(r, data, i, elem)\ BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, elem) #define MACRO1(r, data, i, elem)\ BOOST_PP_SEQ_FOR_EACH_I_R(r, MACRO2, ~, elem) #define MACRO2(r, data, i, elem)\ elem BOOST_PP_SEQ_FOR_EACH_I(MACRO, ~, seq) BOOST_PP_SEQ_FOR_EACH_I(MACRO1, ~, seq) Both preprocessors I tried, VC71 and GCC 3.4.2, produce the same result: BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, (1)(2)(3) ) BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, (4)(5)(6) ) BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, (7)(8)(9) ) BOOST_PP_SEQ_FOR_EACH_I_M(3, (MACRO2, ~, (1)(2)(3) (nil), 0)) BOOST_PP_SEQ_FOR_EACH_I_M(4, (MACRO2, ~, (2)(3) (nil), 1)) BOOST_PP_SEQ_FOR_EACH_I_M(5, (MACRO2, ~, (3) (nil), 2)) BOOST_PP_SEQ_FOR_EACH_I_M(4, (MACRO2, ~, (4)(5)(6) (nil), 0)) BOOST_PP_SEQ_FOR_EACH_I_M(5, (MACRO2, ~, (5)(6) (nil), 1)) BOOST_PP_SEQ_FOR_EACH_I_M(6, (MACRO2, ~, (6) (nil), 2)) BOOST_PP_SEQ_FOR_EACH_I_M(5, (MACRO2, ~, (7)(8)(9) (nil), 0)) BOOST_PP_SEQ_FOR_EACH_I_M(6, (MACRO2, ~, (8)(9) (nil), 1)) BOOST_PP_SEQ_FOR_EACH_I_M(7, (MACRO2, ~, (9) (nil), 2)) Which, I think, indicates that reentrancy is not working. Am I missing something? Regards, Arkadiy

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Querying the Interest in a new AutoPtr class?
by Chris Just 13 Feb '05

13 Feb '05

Hi all, I was wondering what the interest level is for a new auto pointer? I know you've got a few different ones already, but I believe this one has some features that make it quite unique. I based my AutoPtr from the STL auto_ptr and added some additional operator overloads to make it easier to use. The biggest feature however, is that you can specify a custom deletion function object. The custom deletion function object allows you to delete in ways other than just 'delete ptr;' For example, you can delete like this: delete [] ptr; ptr->Delete(); // Delete() calls: delete this; free( ptr ); If you want to take a look at it, it's available at: http://groups.yahoo.com/group/boost/files/AutoPtr/ I'd like to hear your suggestions. Chris Just __________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard. http://promotions.yahoo.com/new_mail

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thread safety in boost intrusive and shared pointers
by Puneet Jain 13 Feb '05

13 Feb '05

I am a new user of boost pointers and was wondering about the thread safety in boost shared and intrusive pointers. After reading some eariler posts and the current documentation, I am little confused. As per current documentation shared pointers thread safety in shared pointers is on the lines of STL and thus they are not thread safe for writing. But I am pretty sure I read in one of the posts that shared pointer is thread safe for all operations. Also, looking at the operator= and swap, it seems there could be some thread safety issues. Also, I have my own counted_base which I use in intrusive pointer. If my understanding is correct, to ensure thread safety, if I ensure add_ref and release_ref operations are atomic, I am pretty much covering all the bases. Thanks, Pete

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[date_time] errors in compiler_config.hpp
by Martin Wille 13 Feb '05

13 Feb '05

Hi, there are several missing logical operators around line 17 of date_time/compiler_config.hpp Regards, m

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Boost filesystem and windows drives
by jrg＠dsl.pipex.com 13 Feb '05

13 Feb '05

Boost filesystem paths checked using filsystem::windows_name cannot contain a colon (":"). But the standard way to specify a particular drive in Windows is to use a colon (e.g. "C:\Windows"). Shouldn't colons be allowed for specifying a drive in Windows? Thanks, James

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[config] How to test for GCC <= 4.0
by Jonathan Turkanis 12 Feb '05

12 Feb '05

Hi, I have a workaround which I want to apply to all known versions of GCC but not to future versions unless I later determine that it is necessary. Currently I have something like this: #if !defined(BOOST_INTEL) && ( BOOST_WORKAROUND(__GNUC__, <= 3) || \ BOOST_WORKAROUND(__GNUC__, == 4) && \ BOOST_WORKAROUND(__GNUC_MINOR__, BOOST_TESTED_AT(0)) ) \ /**/ ... #endif but I can see from the regression reports that GCC 4.0 is not picking up the workaround code. What am I doing wrong? Jonathan .

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Singleton Library Ready for Review
by Jason Hise 12 Feb '05

12 Feb '05

Recent changes: * The dependency lifetime now works by using the pointers themselves as dependencies, and using lazy creation to determine whether creation of the pointer or dereferencing of the pointer creates the instance. Using the pointer instead of a separate dependency class allows the lifetime to achieve a consistent interface with the other lifetime policies. * All lifetime policies now work uniformly for Singletons, Multitons, and potentially any Somethingtons that an end user might choose to implement (HashedMultiton, TwoKeyedMultiton, etc...). The only caveat is that the Multiton instance holder (a singleton used in the implementation of the multiton), must use a leaky lifetime. If any other type of lifetime is used, combining the longevity lifetime policy with the multiton ends up being disastrous. If the OS cleans up leaked memory when the program exits, this should not be a problem. Even so, I would like to find a better solution if possible. Because I have no experience with multi threading, I need someone to verify that I am locking in all of the right places, and that any singleton/multiton operations that need to be thread safe actually are thread safe. A sample test program is provided below, whose lifetime policies can be easily edited to verify order of creation and destruction in all circumstances. I am fairly confident that my singleton library is now complete. What are the next steps to take in adding it to Boost? -Jason // Sample Program #include <sstream> #include <fstream> #include "../Include/StaticAllocator.h" #include "../Include/MallocAllocator.h" #include "../Include/LongevityLifetime.h" #include "../Include/Singleton.h" #include "../Include/Multiton.h" using namespace boost::singleton; using std::stringstream; using std::ofstream; class TestLog : public Singleton < TestLog, LongevityLifetime < TestLog, 10 > > { private: ofstream out; protected: TestLog ( ) : out ( "log.dat" ) { out << "Test log created.\n"; } ~ TestLog ( ) { out << "Test log destroyed.\n"; out.close ( ); } public: void Write ( const char * msg ) { out << msg; } }; class A : public Multiton < int, A, LongevityLifetime < A, 5 > > { private: TestLog :: Pointer log; protected: A ( ) { log->Write ( "A created.\n" ); } ~ A ( ) { log->Write ( "A destroyed.\n" ); } }; // lifetime longevity higher than A, to verify that even though A is created first, it is still destroyed after B class B : public Singleton < B, LongevityLifetime < B, 7 > > { private: TestLog :: Pointer log; A :: Pointer a1; A :: Pointer a2; A :: Pointer a3; protected: B ( ) : a1 ( 0 ), a2 ( 1 ), a3 ( 1 ) { log->Write ( "B created.\n" ); } ~ B ( ) { log->Write ( "B destroyed.\n" ); } public: void foo ( ) { log->Write ( "foo called.\n" ); } }; int main ( ) { B::Pointer ptr; ptr->foo ( ); }

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CVS has a stale lock
by Carlo Wood 12 Feb '05

12 Feb '05

This is majorly annoying, can this be fixed ASAP please? cvs checkout: Updating boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:46:22] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:46:52] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:47:22] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:47:52] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:48:22] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:48:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:49:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:49:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:50:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:50:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:51:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:51:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:52:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:52:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:53:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:53:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:54:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:54:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:55:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:55:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:56:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:56:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:57:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:57:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:58:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:58:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:59:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [04:59:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:00:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:00:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:01:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:01:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:02:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:02:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:03:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:03:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:04:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:04:53] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:05:23] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:05:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:06:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:06:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:07:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:07:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:08:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:08:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:09:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:09:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:10:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:10:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:11:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:11:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:12:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:12:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:13:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:13:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:14:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:14:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:15:24] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib cvs checkout: [05:15:54] waiting for david_abrahams's lock in /cvsroot/boost/boost/tools/build/v1/example/sublib_use/sublib etc -- Carlo Wood <carlo(a)alinoe.com>

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unit-test always seg-faulting
by amerio 12 Feb '05

12 Feb '05

Hello, We are trying to use boost unit test framework for our unit tests. It works fine, except it will always seg fault when quitting. Even the smallest simplest empty test will seg fault. Compiler is gcc 2.95.4, on a Woody Debian. Compiling with -g -pg -pthread Linking with -g -pg -lboost_thread-gcc-mt -lboost_unit_test_framework-gcc-1_32 unit_test.cpp is only : #define BOOST_AUTO_TEST_MAIN #include <boost/test/auto_unit_test.hpp> #include <iostream> BOOST_AUTO_UNIT_TEST(autofct) { std::cout <<"ok" << std::endl; } Seg fault is when calling dispose(), in shared_count::release() (line 147) Thanks for your help.

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Unordered associative containers and swap's exception safety
by Daniel James 12 Feb '05

12 Feb '05

Hello everyone, I've got an exception safety problem implementing the hash containers. The draft standard says (from 6.3.1.1): 'For unordered associative containers, no swap function throws an exception unless that exception is thrown by the copy constructor or copy assignment operator of the container's Hash or [equality] Pred object (if any).' This is a problem, because for the container to be valid, its hash buckets, equality predicate and hash function need to consistent. Since both the hash and predicate can throw, this is impossible (or hard?) to achieve. If swapping/copying the first one succeeds, and the second one throws they won't match. Any ideas on what I should do? I don't think this can cause any major problems, like memory leaks or access to unowned memory, but it can cause unpredictable behaviour - since equal keys can end up in different buckets. Basically the invariant ends up totally broken. The only solution that I've come up with, is to store the two function objects in a seperate structure, allocated on the heap, so that only pointers have to be swapped. But this seems unfortunate since most function objects won't throw. This problem also applies to the copy assignment operator. Daniel

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