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[function] function wrapping with no exception safety guarantee
by Daniel Walker 15 Nov '10

15 Nov '10

Hi all, A few weeks ago, there was a request to remove boost::function's dependency on boost::throw_exception when the user ensures that boost::function is always initialized before attempting a call. https://svn.boost.org/trac/boost/ticket/4646 Providing an alternative invocation method in addition to the call operator is an unattractive solution for many reasons; e.g. boost::function would be less function-like syntacticly. Instead, why not provide an alternative function wrapper with no exception safety guarantee and no dependency on boost::throw_exception? Thanks to Boost.Function's implementation design, which uses preprocessor metaprogramming to generate many function wrappers with different arities, it is simple to generate a function wrapper with no exception safety guarantee. I have submitted a feature request with a patch that implements boost::unsafe_function -- a function wrapper with no exception safety guarantee -- along with tests and updated documentation. https://svn.boost.org/trac/boost/ticket/4720 unsafe_function's API and semantics are identical to boost::function except that the behavior of operator() is undefined when uninitialized. Also, swap, constructor and assignment operators have been added to allow an unsafe_function to wrap the target of a boost::function and vice versa. unsafe_function is primarily useful in certain environments in which exceptions and/or compiler optimizations are unavailable, such as some embedded systems. On contemporary PC hardware, unsafe_function typically would not have an advantage over boost::function. For example, with object code generated by gcc -O2, I could only detect a ~1% difference between the two in terms of runtime costs using a simple benchmark; i.e. less than a nanosecond. However, with -O1, unsafe_function costs ~15% less than boost::function due to the lack of overhead from the strong exception safety guarantee. Thoughts? Daniel Walker

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[1.45][thread] TSS showstopper?
by John Maddock 15 Nov '10

15 Nov '10

The recent changes to Boost.Thread in both Trunk and Release branches have broken one of the regex tests: testing.capture-output ..\..\..\bin.v2\libs\regex\test\regex_regress_threaded.test\msvc-10.0\debug\asynch-exceptions-on\threading-multi\regex_regress_threaded.run ====== BEGIN OUTPUT ====== TSS Initialisation failed with message: boost::thread_resource_error **** error return code: -1 ******** errors detected; see standard output for details ******** EXIT STATUS: 1 ====== END OUTPUT ====== I assume it's quite likely that if this effects the regex lib, then it will equally impact on user code that uses thread_specific_pointer? Regards, John.

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Re: [boost] [Boost-commit] svn:boost r66577 - trunk/libs/numeric/ublas/test
by Jürgen Hunold 15 Nov '10

15 Nov '10

Hi David, This commit On Sunday, 14. November 2010 20:34:07 david.bellot(a)gmail.com wrote: > Author: david.bellot > Date: 2010-11-14 14:34:04 EST (Sun, 14 Nov 2010) > New Revision: 66577 > URL: http://svn.boost.org/trac/boost/changeset/66577 > > Log: > update jamfile > > Text files modified: > trunk/libs/numeric/ublas/test/Jamfile.v2 | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > Modified: trunk/libs/numeric/ublas/test/Jamfile.v2 > ============================================================================ --- trunk/libs/numeric/ublas/test/Jamfile.v2 (original) > +++ trunk/libs/numeric/ublas/test/Jamfile.v2 2010-11-14 14:34:04 EST > (Sun, 14 Nov 2010) @@ -134,4 +134,6 @@ > ] > [ run test_assignment.cpp > ] > + [ test_boost_ublas_size_0.cpp > + ] > ; just broke the test. First, the call is totally wrong, should read "run test_boost-..." ../libs/numeric/ublas/test/Jamfile.v2:138: in modules.load rule test_boost_ublas_size_0.cpp unknown in module Jamfile</home/hunold/src/devel/boost/libs/numeric/ublas/test>. Second,test_boost_ublas_size_0.cpp is missing from svn. error: Unable to find file or target named error: 'test_boost_ublas_size_0.cpp' error: referred from project at error: '.' Please add at least the missing file. Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! Ingenieurgesellschaft für * voice: ++49 511 262926 57 ! Verkehrs- und Eisenbahnwesen mbH * fax : ++49 511 262926 99 ! Lister Straße 15 * juergen.hunold(a)ivembh.de ! www.ivembh.de * * Geschäftsführer: ! Sitz des Unternehmens: Hannover * Prof. Dr.-Ing. Thomas Siefer ! Amtsgericht Hannover, HRB 56965 * PD Dr.-Ing. Alfons Radtke !

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[1.45] Where are we in the release process?
by John Maddock 14 Nov '10

14 Nov '10

I'm asking because someone's just assigned a Boost.Interval issue to me: https://svn.boost.org/trac/boost/ticket/4799#comment:1 Seems like there is a trivial fix in Trunk, but as the library appears not to have been maintained for while, it looks like none of the patches that some folks have applied to Trunk have been merged to release :-( On a related note, I believe there are quite a few old and unmerged changes to the Utility lib as well. We really need to figure out a better way of dealing with this... John.

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Minimizing Dependencies within Generic Classes for Faster and Smaller Programs
by vicente.botet 14 Nov '10

14 Nov '10

Hi, I have found this paper "Minimizing Dependencies within Generic Classes for Faster and Smaller Programs" http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2911.pdf quite iteresting. The gain in performances and reduced space could be considerable. I was wondering if Boost should not take this as a guideline and whether the Boost authors would check his libraries to see if this technique could improve its performances, in particular for all the container and the the forthcomming Boost.Container libraries. I would be interested in knowing if this has been adopted for C==0x containers. Good reading, _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

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Standard stream from C fopen()
by Claude 14 Nov '10

14 Nov '10

Hi! I Use this code for make a standard stream from a C fopen() FILE* : FILE *fd = fopen("Prova", "w"); if (fd) { // io::stream_buffer<io::file_descriptor_source> fpstream (fileno(fd)); //std::istream in (&fpstream); istream in = boost::iostreams::file_descriptor(fileno(fd)); } But I obtain an error (G++ on Linux Ubuntu): [...] error: conversion from ‘boost::iostreams::file_descriptor’ to non-scalar type ‘std::istream’ requested| [...] error: call of overloaded ‘path(const int&)’ is ambiguous| [...] Why? What is the correct method? -- View this message in context: http://boost.2283326.n4.nabble.com/Standard-stream-from-C-fopen-tp3040002p3… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[1.45.0] Permission to merge trunk to release for Boost.Optional
by Fernando Cacciola 13 Nov '10

13 Nov '10

Hi, As reported by Eric Niebler, the release brunch did not had the swap member that existed in the trunk for a long time. I just merged it locally and run the tests on the release branch. Can I commit the changes? P.S: The test suite changed as well due to the different swap. P.S.2: I've also been reported on a couple of minor documentation issues, so I've fixed this on both the trunk and the release branch. P.S.3: Going over all the differences I've found a trivial change in the testsuite for value_initialized: The trunk version uses the lightweight "minimal" test tools instead of the full test tools. I've merged this one as well. Can I commit these changes to the release branch? --- Fernando Cacciola SciSoft Consulting, Founder http://www.scisoft-consulting.com

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[FunctionTypes] Removing the ClassTransform when invoking parameter_types
by Edward Diener 12 Nov '10

12 Nov '10

When invoking boost::function_types::parameter_types with a member function pointer as the first template parameter, what do I susbstitute as the second template parameter so that no transform is done ?

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[exception] [1.44] you own a showstopper
by Eric Niebler 12 Nov '10

12 Nov '10

Emil, The following bug in exception is marked as a Showstopper for the 1.44 release. What are your plans for it? If you're planning on fixing it, can you do so soon? If you feel it is not a showstopper, can you set its priority appropriately? https://svn.boost.org/trac/boost/ticket/4768 Thanks, -- Eric Niebler BoostPro Computing http://www.boostpro.com

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Type traits extension & Bitfield reviews
by Joel Falcou 12 Nov '10

12 Nov '10

I've just seen these libraries hanging out in the review queue for quite some time now. Considering their potential usefulness adn my personnal interest, I consider stepping up as a review manager for these. What's the formal sequence to follow to apply for such a task ?

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