April 2008 - Boost-users - lists.preview.boost.org

[Boost][Signals]Can a threadpool implementation be done using signals??
by sankar lingam 06 Apr '08

06 Apr '08

I had a look into boost Signals and I just want to know whether a threadpool implementation can be done using signals(as they are thread safe).? However will this be efficient in terms of performance when I do the threadpool implementation using a thread safe queue(guarded by mutexes) where in tasks are queued into the queue and worker threads in the threadpool pick out tasks and execute them.. Regards, Sankar

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Does MPI use ASIO?
by Jeff 06 Apr '08

06 Apr '08

Hello everyone, Does the new MPI Library use ASIO for its network ops? Thanks, Jeff

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[GIL] image_view::size_type and out of core images on 32 bits platforms
by N L 06 Apr '08

06 Apr '08

Hi everyone, I'm currently setting up an image processing pipeline for large (out of core) GIS images using GIL. I'm quite glad with the results I get right now, but I stumbled upon a problem with the default image_view size / iterator handling. Currently, image_view::size_type is defined as std::size_t, and image_view::end is implemented as begin()+(difference_type)size<http://stlab.adobe.com/gil/html/structboost_1_1gil_1_1size.html> (); As my images pixel count exceed the max value of std::size_t on my dev platform (win32), the image_view::end member function fails to give a valid iterator... As nearly every types defined in image_view are given by the templated locator type, I'm thinking that the size_type should not be an exception, and should be given by the locator type. I also tend to think that the 'image iterators' should not share the difference_type type with the '1D iterators' - but these are mainly performance considerations in my case, as my image iterators should be 64bits, and my 1d iterators can be 32 bits. For now, I changed my GIL working copy to patch image_view definition, as I did not see any way to work around the iterator problem. Did I miss anything ? Is there any user-level workaround I could use, or should the image_view class be modified ? Any thoughts would be welcome :) Thanks, Nicolas.

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boost::asio::deadline_timer - Invalid Argument
by j.c. 06 Apr '08

06 Apr '08

Hi, I have a deadline_timer object that fires every second to perform network house keeping tasks. I am having what looks like a race condition or runaway IO when my timer fires and performs an async_connect. The following is my output: parent_connection::tick parent_connection::connect: trying next address:port 10.0.1.198:4315 Press any key to continue... CONNECTING ===> 10.0.1.198 CONNECT FAILED: Connection refused 00:00:01.001559 parent_connection_manager::disconnected parent_connection::connect: trying next address:port 10.0.1.198:4316 CONNECTING ===> 10.0.1.198 CONNECT FAILED: Invalid argument 00:00:01.002813 parent_connection_manager::disconnected parent_connection::connect: trying next address:port 10.0.1.198:4317 CONNECTING ===> 10.0.1.198 CONNECT FAILED: Invalid argument 00:00:01.000404 parent_connection_manager::disconnected parent_connection::connect: trying next address:port 10.0.1.198:4318 CONNECTING ===> 10.0.1.198 CONNECT FAILED: Invalid argument 00:00:01.000449 parent_connection_manager::disconnected parent_connection::connect: trying next address:port 10.0.1.198:4319 CONNECTING ===> 10.0.1.198 CONNECT FAILED: Invalid argument * Note the first call succeeds because it was not called from with a timer. So I guess the question is "How can I call async sockets on the same io_service trough a timer?" thanks in advance jc

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[1.35.0][build] where o where have my little libs and dlls gone?
by Andrew Schweitzer 06 Apr '08

06 Apr '08

[bjam --toolset=msvc stage] doesn't seem to generate nearly as much as it used to, and my vc8 program now complains it can't find: libboost_program_options-vc80-mt-sgd-1_35.lib I can't find it either... I tried the latest bjam, 3.1.16. I tried --build_type=complete, I tried -a. I suspect I'm doing something obvious wrong... any suggestions? Thanks, Andy

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regex tr1 constructor
by gast128 05 Apr '08

05 Apr '08

Dear all, Peter Becker's book 'the c++ standard library extensions' describes various tr1::regex constructors. One of them is the following (16.4.2, p.387): char expr1[] = "abc[d-f]"; regex rgx2(expr1, 3); >From the boost headers I can see that it picks up the wrong costructor, since the constructor with length specification has 3 arguments (and the last has no default specification). Who is wrong? I am using Visual Studio 2003 and boost 1.34.0.

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[Accumulators] Iterate through values in an accumulator_set
by Olivier Tournaire 05 Apr '08

05 Apr '08

Hi all, I would like to know if it is possible to iterate through the values of an accumulator_set. I know how to fill the accumalator, extract results, but not how the get the values it contains. Best regards, Olivier

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boost::accumulators and boost 1.35
by Olivier Tournaire 05 Apr '08

05 Apr '08

Hi all, I m trying to compile a small piece of code using boost::accumulators. I have compile problems : fatal error C1083: Impossible d'ouvrir le fichier include : 'boost/fusion/sequence/adapted/mpl.hpp' : No such file or directory This file does not exist in the boost svn trunk. I downloaded the accumulators lib from boost vault. So, is boost::accumulators still compliant with boost 1.35 ? Another question : as this library has been accepted, could you tell me why it is not in the last boost release ? Best regards, Olivier

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Floating Point Utilities Review Result
by John Maddock 05 Apr '08

05 Apr '08

Floating Point Utilities Review Result. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There were 6 positive reviews and no negative ones, so Johan Rade's Floating Point Utility library has been accepted into Boost. The main issues and topics that came up for discussion were: 1) A couple of minor bugs were uncovered relating to signed NaN testing when using the SSE2 registers, and deserialising NaN's: both were fixed during the review period. 2) We had a discussion about the usefulness or otherwise of signed NaN's and the changesign function: Johan agreed to drop support for these as the signbit of NaN's is not considered part of the NaN payload and need not be preserved by the compiler, this could usefully be summarised in a rationale: especially now that negative NaN's are not formatted with a "-" sign? 3) JM made a few quite fruitless suggestions about optimising away calls to memcpy: this should be documented in a rationale to prevent JM from making the same mistake again :-) 4) John Phillips raised the issue of finding these tools - making sure that they don't get lost amongst all the other special functions and "stuff" in Boost.Math. JM and Johan have agreed to work together to ensure this doesn't happen. 5) There were a couple of suggestions for a convenience function for installing the facets in a locale/iostream: Johan agreed to add this. 6) There was +1 vote for manipulators rather than flags to the facet constructors - further investigation suggested this was problematic in a header only library - so the suggestion was dropped. 7) There was one comment about the library not using quickbook for documentation: ideally it would be nice to see this fixed so that the docs integrate seamlessly with the rest of Boost.Math - but see #4 as well. Many thanks to Johan for making these utilities available. John Maddock. Review Manager for the Floating Point Utilities.

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Compiling boost static libraries with vc8
by Sean Farrow 04 Apr '08

04 Apr '08

Hi: How do I compile static libarieswith bjam and vc 8.0? it only seems to compile dlls, when I invoke bjam and it auto detects the toolset. Any help apreciated. Sean.

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