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Fwd: Lexical cast between narrow and wide strings
by Andrew Marlow 11 Jun '14

11 Jun '14

I hope this is the right place to post my question. I expected to be able to convert between narrow and wide strings using boost lexical cast but it fails to compile. I suppose that conversion is not supplied or supported. It would be really useful to me if it was. I am developing on win32 for wince and on wince there seeem to be many places where wide strings are required, especially when using the win32 API. Is there any chance this could be added to boost? I checked using boost 1.55.0 -- Regards, Andrew Marlow http://www.andrewpetermarlow.co.uk

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Is boost asio appropriate for this use case ?
by Aaron Boxer 10 Jun '14

10 Jun '14

I am decoding an image file: the file has tagged header info mixed with 4K pixel code blocks. Platform is primarily windows, but could be osx or linux. Once I read in a code block, I can launch (asynchronously) my decode routine on this block, while continuing to read the file for header info and code blocks. Currently, I do synchronous reads using fread(...). Is is worthwhile to switch to boost asio to asynchronously read in the code blocks? The read callback could trigger my decode routine. But I wouldn't have to wait for the read before I carry on to the next code block. If so, can anyone point me to a reference/tutorial covering boost::asio asynch reads from disk?

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[boost] [pimpl] Boost.Pimpl review canceled
by Glen Fernandes 09 Jun '14

09 Jun '14

Hi everyone, Vladimir has elected to withdraw Boost.Pimpl submission and cancel the formal review. On behalf of Vladimir, thank you for the feedback provided in response to the pre-view announcement mail: it was especially useful to him. Best, Glen

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memory mapped file thread safety
by Aaron Boxer 09 Jun '14

09 Jun '14

Simple question: If I call get_address() on a region, can I pass this pointer to another thread and have this thread access the memory ? Thanks!

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Boost Build
by skk 09 Jun '14

09 Jun '14

I am building Boost for MSVS10.0. I have generated the bjam.exe file and run it with the command line: bjam toolset=msvc10.0 variant=debug,release threading=multi link=static Looking at the libraries built, there are no sgd libs and the linker wants: libboost_regex-vc100-mt-sgd-1_55.lib Don't know how to get the sgd libs. Thanks -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-Build-tp4663758.html Sent from the Boost - Users mailing list archive at Nabble.com.

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[Filesystem] remove and recursive_directory_iterator
by gast128 09 Jun '14

09 Jun '14

I couldn't find a description of the iterator stability of recursive_directory_iterator but it gives problems when you remove the directory which is being iterated even when that directory is empty. For example if you want to remove all empty directories, the following code will throw an exception in ++it after the 'remove' call: fs::path pthDirectory = ...; fs::recursive_directory_iterator itEnd; for (fs::recursive_directory_iterator it(pthDirectory); it != itEnd; ++it) { boost::system::error_code ec; const fs::path& rPath = it->path(); if (fs::is_directory(rPath, ec)) { if (fs::is_empty(rPath, ec)) { fs::remove(rPath, ec); } } } It seems solvable with the way one erases a map (i.e. using while (it != itEnd) and using the equivalent of map.erase(it++)). Maybe add a note to the documentation or did I overlook something?

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Writing a dynamic string into a shared memory using Boost Library
by Hany Assasa 09 Jun '14

09 Jun '14

I want to share a dynamic array of characters between two processes using Boost Shared Memory. I use the following two pieces of code to do that: *Producer Process:* char *data;unsigned int share_length;unsigned int offset; std::string data_to_share(data + offset, data + offset + share_length); boost::interprocess::managed_shared_memory managed_shm(boost::interprocess::create_only, "SomeName", 1024*1024);typedef boost::interprocess::allocator<char, boost::interprocess::managed_shared_memory::segment_manager> CharAllocator;typedef boost::interprocess::basic_string<char, std::char_traits<char>, CharAllocator> my_string; managed_shm.construct<my_string>("DataToShare")(data_to_share.c_str(), managed_shm.get_segment_manager()); *Consumer Process:* boost::interprocess::managed_shared_memory managed_shm(boost::interprocess::open_read_only, "SomeName");typedef boost::interprocess::allocator<char, boost::interprocess::managed_shared_memory::segment_manager> CharAllocator;typedef boost::interprocess::basic_string<char, std::char_traits<char>, CharAllocator> my_string; std::pair<my_string *, size_t > data = managed_shm.find<my_string>("DataToShare"); cout << "Data Size=" << data.first->length() << endl; The problem is when I try to print the length of the DataToShare in the Consumer Process it is wrong, so what is the problem in my code, is it in the Producer Part since I am doing data_to_share.c_str()which is a std::string type instead of of my_string type? *Possible Answer:* I believe the answer to my question is, converting std::string into my_string type. so can anyone tell me how to do that?

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[mpl] Cannot open include file
by Christian Henning 09 Jun '14

09 Jun '14

I have the following error when using Visual Studio 2013 on the boost master branch: 1>c:\boost\boost\mpl\vector\aux_\include_preprocessed.hpp(49): fatal error C1083: Cannot open include file: 'boost/mpl/vector/aux_/preprocessed/plain/vector10.hpp': No such file or directory I have run "b2 headers". Here is the code I'm trying to compile: // cpp_test.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <boost/mpl/vector_c.hpp> int _tmain(int argc, _TCHAR* argv[]) { return 0; } Manually I can find vector10.hpp in C:\boost\boost\mpl\vector but I don't have the folder c:/boost/mpl/vector/aux_/preprocessed/plain/ Any ideas? Thanks, Christian Regards, Christian

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Using a vertex type
by Mads Jensen 09 Jun '14

09 Jun '14

Hi, I'm planning on writing an implementation of the Gomory Hu cut tree algorithm (for learning purposes, and as a side bonus, have some code in open source), but have some initial difficulties. I posted some code at: http://codepad.org/yTt3xNsK I had tried something like: template<class OrdinaryVertex> struct gomory_hu_vertex { std::vector<OrdinaryVertex> vertices; }; and the graph definition: typedef adjacency_list<listS, vecS, undirectedS, GHVertex> GHGraph; but with the insert operation, I get a compiler error. When I get it working, I want to submit it to the boost library. Are there restrictions on what type of features you can use, e.g., anything from C++11 is ruled out? Thank you, Mads

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[serialization] serialize object tree and values
by Daniel Krikun 07 Jun '14

07 Jun '14

Hello, I have an application which creates some objects connected between them using boost::shared_ptr and then executes a main loop. The object graph structure is almost constant over time but primitive member fields of the objects change over time. I would like to serialize the whole object graph *each cycle* saving both the object graph structure and primitive member fields. Currently I don't know how to achieve this: when I try to serialize via pointer only first value is saved. Also, I'm not sure if I should turn object tracking off, because indeed it should be a single instance of each, it just should be modified over time. Thanks!

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