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[interprocess][multi_index] emplace() is not sufficient for maps
by Thorsten Ottosen 25 Sep '09

25 Sep '09

Hi Ion and Joaquín, This issue is related to node-based containers. I think you both have added emplace() to provide efficient in-place construction. However, I often encounter a situation where emplace() is not sufficient for me. The situation is characterized by the need to calculate the key after the mapped value (a heavy object) has been placed in the pair. To calculate the key the mapped value needs to be modified (the key is calculated as a side-effect). I therefore suggest that we add a new function: typedef ... map; map m; map::node_ptr p = m.get_node_ptr(<like emplace, but only for constructing the mapped value>); p->pair.first = modify( p->pair.second ); m.insert( boost::move(p) ); Thoughts? -Thorsten

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Boost build problem
by Emil Dotchevski 25 Sep '09

25 Sep '09

I'm trying to use <link>static and <runtime-link>static with my own code, which depends on boost filesystem, and I have the problem that the linker is passed libboost_filesystem-vc80-mt-sgd-1_41.lib while the debug\link-static\runtime-link-static folder has libboost_filesystem-vc80-sgd-1_41.lib. (I've built bjam from the latest trunk sources and I'm using the latest trunk revision of boost build.) HALP! :) Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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[rdb] Uploaded 0.0.08
by Jean-Louis Leroy 24 Sep '09

24 Sep '09

Tonight: * insert...where (but doesn't check consistency between insert list and values returned form select) * like J-L

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boost::variant -- this code compiles fine -- I think it should not compile
by Peter Foelsche 24 Sep '09

24 Sep '09

#include <boost/variant.hpp> struct test { }; int main(int argc, char **argv) { boost::variant<std::string, int, double> s; boost::get<test>(s); return 0; }

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Matrix Library
by Cem Kalyoncu 24 Sep '09

24 Sep '09

As a part of our graphics study, we have built a 2D matrix class to implement few matrix operation. After the study we have expanded our aim for matrix operations system and started building a matrix and possibly a math library. Currently matrix library is quite near to the finish. To make it as generic as possible, we have used templates. Current state of the project can be accessed from http://sourceforge.net/projects/mathlibcpp/ (SVN: https://mathlibcpp.svn.sourceforge.net/svnroot/mathlibcpp/) A simple search revealed that there is no matrix module for boost libraries. We are willing to resolve compatibility issues and lend our support this module. However, before taking any action, I would like to ask your opinions. Thanks in advance, Cem Kalyoncu Following functions exists in the library: Set/Get/GetData/() Resize/GetSize/GetCols/GetRows isSquare/isIdentity Compare/==/!= =/Copy constructor/CopyTo [Row|Col|]Min/Max/Average/Sum/Median [Row|Col]MinIndex/MaxIndex SortRows RemoveCol/RemoveRow matrix operators (+, -, *, +=, -=, *=) scalar operator (+, -, /, *, +=, -=, *=, /=) Transpose/Determinant/Inverse/Minor/Cofactor/Adjoint Uses a managedbuffer and allows temporary matrixes which are not copied Identity/ZeroFilled/RandomFilled/RobertsCross/SobelX|Y conversion to string and output to a stream is supported

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pool allocation
by Stefan Strasser 24 Sep '09

24 Sep '09

I took a closer look at Boost.Pool today to replace some default allocation of small objects. what I found there was a little disappointing, at least for my use case. the object_pool has 2 major downsides: - no dynamic block allocation - destroying one(!) object is O(N), with N being the number of unused objects in the pool so I wrote some code for my own use. I'm not suggesting this code should be added to boost, but something like it. struct A{ ... }; { pool<A,100> pool; A *a; for(int c=0;c<250;++c){ a=pool.new_(); // O(1) } pool.delete_(a); //O(1), destructs } //destruction of 249 objects, O(N) this allocates 3 memory blocks. but it also has one pointer memory overhead per object, to achieve constant time deletion. but you can use that pointer while the object is in use, which was what lead to this code: I needed to store unused boost.intrusive nodes: struct A : intrusive::[s]list_base_hook<>{ ... }; { [s]list_pool<A,[s]list_base_hook<>,100> pool; //same as above } this has no memory overhead, as the list hook can be used by the pool. here's the code: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=intrus…

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[asio] Mixing of sync and async calls
by Roland Schwarz 24 Sep '09

24 Sep '09

Is it legal to mix async and sync function calls? (I was not able to find the answer in the doc.) E.g. socket.async_read_some(buf); socket.write_some(otherbuf); Also when in a blocking sync call, will it be possible to "cancel" it from another thread, e.g. by posting to the io_service which will invoke a close on the socket? Thank you in advance. -- _________________________________________ _ _ | Roland Schwarz aka. speedsnail |_)(_ | sip:speedsnail@ekiga.net | \__) | mailto:roland.schwarz@chello.at ________| http://www.blackspace.at

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[BGL] read_graphviz()/read_graphml() and subgraphs
by Giuseppe Di Guglielmo 24 Sep '09

24 Sep '09

Dear all, I read on the 'read_graphviz()' page in BGL library doc http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/read_graphviz.html * read_graphviz treats subgraphs as syntactic sugar. It does not reflect subgraphs as actual entities in the BGL. Rather, they are used to shorten some edge definitions as well as to give a subset of all nodes or edges certain properties. For example, the DOT graphs digraph { a -> subgraph {b -> c} -> e } and digraph { a -> b -> e ; a -> c -> e ; b -> c} are equivalent. Is this actually true? Can I read sub-graph from DOT description and obtain a subgraph object? http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/subgraph.html Eventually are subgraph supported by 'read_graphml()' function? http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/read_graphml.html Thanks, G.

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[multi_index] Missing mutex lock?
by Anatoly Pinchuk 23 Sep '09

23 Sep '09

Possible traversal and modifications of a safe container iterators list inside safe_mode::detach_equivalent_iterators function are not protected with locking like the following one in safe_iterator_base::detach function. #if defined(BOOST_HAS_THREADS) boost::detail::lightweight_mutex::scoped_lock lock(cont->mutex); #endif Unless some kind of synchronization is provided by callers of the safe_mode API, the list above can be traversed/modified and modified concurrently in BOOST_HAS_THREADS environment. It would be great if somebody can confirm or deny that there is the access synchronization problem. Regards, Anatoly

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Re: [boost] scoped_ptr deleter
by Berserker 22 Sep '09

22 Sep '09

Stewart, Robert wrote: > That change creates multiple, distinct classes. > shared_ptr<T,boost::checked_deleter<T>> is not the same as shared_ptr<T,my_deleter<T>>. > By embedding the deleter in the shared_ptr with type erasure, > shared_ptr<T> is shared_ptr<T> is shared_ptr<T>, regardless of the deleter. Sure and that's the point :) As I wrote, since the "noncopyable nature" of scoped_ptr (shared_ptr is copiable by design), the creation of distinct classes isn't a problem. I think that the "real problem" here is to provide a solution that doesn't require extra memory overhead. _________________________________________________________________ Gossip, Sport, Notizie... Accendi la Messenger TV! http://www.messenger.it/messengerTV.aspx

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Re: [boost] [Boost-users] Parallel BGL status in Boost
by Craig Henderson 22 Sep '09

22 Sep '09

> Nick Edmonds wrote: > >> On Sat, Sep 12, 2009 at 9:42 PM, Nick Edmonds > <ngedmond(a)cs.indiana.edu> wrote: > >> > >>> yet). There's also a very nascent project to do multi-core/highly > >>> multi-threaded BGL, starting from the BGL sources as opposed to > PBGL. > >> > >> Any pointers ? It would be nice if they look at using the map-reduce > >> library (boost candidate) > >> > > It's very early stages so no, no docs/code yet, it's basically some > new PhD students in my lab with me and another post-doc mentoring > them. I would anticipate that map-reduce is too > coarse-grained/BSP-like to capture the fine grained dependencies we > need to capture to get good performance in a memory-bandwidth bound > domain like sparse graphs, but I'll mention it and see if they want to > write a sample algorithm with it and run some numbers. We're > investigating a few different options for organizing/parallelizing the > work, including starting from scratch. > > It would be nice to see how the map-reduce library performs though. > Do you have any performance data for using it on highly multi-threaded > architectures (Sun Niagara, Cray XMT, anything with >8 cores really)? > Hi Nick, the Map/Reduce library is available in the sandbox and in the vault. The performance is as much down to the implementation of the map and reduce tasks as the framework itself. Jose has compared performance of my library with Standford University's Pheonix implementation and the performance is comparable (http://lists.boost.org/Archives/boost/2009/08/155759.php) I have tested the library on MS Windows on servers with 16-cores and performance has scaled well - if you get the input's segregated sufficiently to avoid contention. I don't yet have any benchmarks, but am looking for some suitable algorithms if you're interested in contributing. Regards -- Craig

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Creating a new toolset for System i *SRVPGMs
by Jon Brisbin 22 Sep '09

22 Sep '09

We're integrating our C++ development with our RPG/400 development and since we use Boost on the PC end, we'd really like to use Boost on the AS400/System i integration stuff. I can successfully compile service programs on the 400 that use boost header-only libraries (with some minor tweaking of the Boost source...I'm finding various things that have to be changed to accommodate the 400 compiler) using the "ixlc" compiler. I think what I need to do to use Boost.Build on the 400 is to create a new toolset that is like gcc, but uses the "ixlc" and "ixlclink" commands to compile *MODULEs and *SRVPGMs. I'm just not familiar enough with Boost.Build to figure out how to do this. I'm actually a Java programmer and not even very experienced in C++, though I've been a unix geek for a long time, so I'm very familiar with the build tools. Since the library/file(member) convention of working with these files on the 400 doesn't translate directly across to files on a unix-like filesystem, I'm thinking I'll have to have directories that correspond to libraries and the source file basename that corresponds to the object name. For example, source file: cpplib/mycpptest.cpp would be compiled using "ixlc" like: ixlc -ocpplib/mycpptest -qdbgview=all -qprint (other options) cpplib/ mycpptest.cpp this would create a *MODULE object called "MYCPPTEST" in library "CPPLIB". How would I translate this to a boost build toolset that I could use by writing a Jamfile like the following...? module cpplib/mycpptest : cpplib/mycpptest.cpp ; srvpgm cpplib/mycpptest : cpplib/mycpptest cpplib/myothrmod ; at some point, I'd probably like to specify a default library, but I can probably do that by using variables in my project's root file. Can anyone help me with this, even though you may not have direct experience with the AS400 (it would be great if there were boost developers who worked on or with 400's, though! ;)? Jon Brisbin Portal Webmaster NPC International, Inc.

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[serialization] serialize shared_from_this() pointer
by Zoran Cvetkov 22 Sep '09

22 Sep '09

Does someone have experience serializing a class that inherits from a shared_from_this() pointer? If I just do nothing I am getting 0 pointer during deserialization. What would be the proper syntax for serializing it, if it's needed?

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review request: addition to type_traits library of is_less_comparable<T> and others
by Frédéric Bron 22 Sep '09

22 Sep '09

Hi folks, I would like to propose to your review the following addition to the type_traits library. The addition is attached to this email and also available in the sandbox at https://svn.boost.org/trac/boost/browser/sandbox/type_traits The purpose of the addition is to add type traits to detect if type T is comparable in the sens of <, <=, >, >=, == or != operators, i.e. if t1<t2 has a sens when t1 and t2 are of type T (same for <=, >, >=, ==, !=). The following traits are added: is_equal_to_comparable<T> is_greater_comparable<T> is_greater_equal_comparable<T> is_less_comparable<T> is_less_equal_comparable<T> is_not_equal_to_comparable<T> The names are based on the corresponding names of the standard template library (<functional> header, section 20.3.3 of the standard). The compilation has been tested with g++ 4.3.2 and icpc 10.0 on linux 64 bits, g++ 3.4.4 on cygwin, mingw32 3.4.4 on cygwin. I must add that I did not invent the code (I obtained some help from the boost mailing list) but I put it together in a form that should be acceptable to boost. Regards, Frédéric

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Possible submission: Dynamic library policy loading library?
by Rob Meijer 22 Sep '09

22 Sep '09

In the Open Computer Forensics Architecture library ( http://sourceforge.net/projects/ocfa/ ), a simple template sub library is used for policy loading with shared libraries. This stuff is currently buried in a large library, and it would seem prety usefull to extract this sub library into an enviroment (like boost) where it can be used within a wider scope. To show apptoximately how this sub library is used, I've taken a few lines from a part of OcfaLib that uses this functionality: The below example is used to load an implementation of the abstract TreeGraphFactory class within a loadable library "libtesttreegraph.so" with a constructor function named "constructor" in it. std::string module="testtreegraph"; //Define a type for the constructor. typedef SinglePointerConstructor< TreeGraphFactory, std::map< std::string,misc::Scalar > > CTreegraphType; //Define a type for the policy loader. typedef PolicyLoader<CTreegraphType> PLTreeGraph; //Create a new policy loader object for a given module and constructor function name. PLTreeGraph *mPolicyLoader=new PolicyLoader<CTreegraphType>(module,"constructor"); //Fetch the constructor from the policy loader. CTreegraphType *constructor = mPolicyLoader->constructor(); //Construct an object using the constructor TreeGraphFactory * mActiveFileSystem =(*constructor)(attributes); For more info, the relevant headers in the ocfa source tree are: OcfaLib/inc/misc/PolicyLoader.hpp OcfaLib/inc/misc/VoidToFunction.hpp It probably needs some work on portability and needs more constuctor templates to be fully generically usable, but I feel this has the potential to be a very usefull extention to boost. Do you people feel this should be further explored and submitted as a possible extension for boost? Rob

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Feed pointers to a container, however use the member of the data type which pointer refer to
by 路邓 22 Sep '09

22 Sep '09

Dear All: In the following codes, I feed the container with B*, however I user the member of B as the index. Can somebody explain to me how this work out? And It seems that if smart pointers are feeded into the container, it still works out. #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */ #include <boost/multi_index_container.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/member.hpp> #include <iostream> using namespace boost::multi_index; class B { public: int idx; }; typedef boost::multi_index_container< B*, indexed_by< ordered_unique< BOOST_MULTI_INDEX_MEMBER(B, int, idx) > > >Container; int main() { Container container; B* p1 = new B; B* p2 = new B; p1->idx = 2; p2->idx = 1; container.insert(p1); container.insert(p2); Container::iterator iter; for(iter=container.begin();iter!=container.end();iter++) { B* tmp = (*iter); std::cout << tmp->idx << std::endl; } return 0; } ___________________________________________________________ 好玩贺卡等你发，邮箱贺卡全新上线！ http://card.mail.cn.yahoo.com/

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Feed pointers to a container, however use the member of the data type which pointer refer to as an index
by 路邓 22 Sep '09

22 Sep '09

Dear All: In the following codes, I feed the container with B*, however I user the member of B as the index. Can somebody explain to me how this work out? And It seems that if smart pointers are feeded into the container, it still works out. #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */ #include <boost/multi_index_container.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/member.hpp> #include <iostream> using namespace boost::multi_index; class B { public: int idx; }; typedef boost::multi_index_container< B*, indexed_by< ordered_unique< BOOST_MULTI_INDEX_MEMBER(B, int, idx) > > >Container; int main() { Container container; B* p1 = new B; B* p2 = new B; p1->idx = 2; p2->idx = 1; container.insert(p1); container.insert(p2); Container::iterator iter; for(iter=container.begin();iter!=container.end();iter++) { B* tmp = (*iter); std::cout << tmp->idx << std::endl; } return 0; } 好玩贺卡等你发，邮箱贺卡全新上线！ ___________________________________________________________ 好玩贺卡等你发，邮箱贺卡全新上线！ http://card.mail.cn.yahoo.com/

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[variant]anyone working on variadic template version?
by Larry Evans 22 Sep '09

22 Sep '09

Is anyone working on a variadic template version of variant, i.e. one that defined as: template<typename... T>class variant; instead of: template < typename T0 = detail::variant::void_ , typename T1 = detail::variant::void_ ... , typename T19 = detail::variant::void_ > class variant; ? I'm thinking of attempting that, but I'd hate to waste time if someone else has already done it or made some progress on it. Although BoostCon09 did have a workshop on CXX0x: http://www.boostcon.com/community/wiki/show/Start/HandsOnCXX0x/ the sandbox directory for that: https://svn.boost.org/svn/boost/sandbox/boost0x didn't appear to use the variadic template feature in variant: https://svn.boost.org/svn/boost/sandbox/boost0x/boost/variant/variant_fwd.h… TIA. -regards, Larry

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[rdb] 0.04
by Jean-Louis Leroy 21 Sep '09

21 Sep '09

I have uploaded a new version of my relational database library to the vault. It implements the ideas I described in another thread. This time it even puts things in a real (odbc) database and retrieves them. I see that 12 have downloaded the previous versions. If you have time please send me feedback. Have you been able to compile it ? Has anybody tried on Unix or with other compilers ? Please note: * It's a work in progress ; for the curious only. * I develop on Windows with Visual Studio Express 2008. There is a solution file in the msvc dir. Nothing bjam works yet. * Currently the doc is the test suite Jean-Louis Leroy

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[rdb] 0.05 - also a fusion problem
by Jean-Louis Leroy 21 Sep '09

21 Sep '09

This upload is mostly for fixing an embarassing bug that the test suite would have detected if I had not put a "return 0" in the middle of it. In addition I have restructured the tests into suites and cases. Jam files begin to work, at least they allow me to build with bjam from the boost tree. While I'm at it, here's the bug, in case somebody has an idea. I have to initially create my fusion::list's of expressions and tables with `push_back(list<>(), val)' instead of just `make_list(val)', otherwise I get access violations. I see in the debugger that the first element of my list is damaged during the next function call, most probably because a reference to a temporary was created along the way. Has anybody had this kind of problem ? I use boost 1.39. J-L

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Problems testing compiling on AS400/i5/whatever
by Jon Brisbin 21 Sep '09

21 Sep '09

I'm using the QSH environment on AS400 and the "ixlc" compiler (basically just CRTCPPMOD), trying to compile the following test program: #include <iostream> #include <boost/foreach.hpp> int main(int argc, char** argv) { std::string hello = "Hello, world!"; BOOST_FOREACH( char ch, hello ) { std::cout << ch << std::endl; } return (EXIT_SUCCESS); } Which results in the following errors: The compilation failed. /home/jbrisbin/include/boost/type_traits/is_member_pointer.hpp Line 000054 "/home/jbrisbin/include/boost/type_traits/ is_member_pointer.hpp", line 54.63: CZP0403(30) "template <class T, class U> struct boost::is_member_pointer<U T::* const>" is alread ERROR 1 001 /home/jbrisbin/include/boost/type_traits/is_member_pointer.hpp Line 000055 "/home/jbrisbin/include/boost/type_traits/ is_member_pointer.hpp", line 55.63: CZP0403(30) "template <class T, class U> struct boost::is_member_pointer<U T::* volatile>" is alr ERROR 1 001 /home/jbrisbin/include/boost/type_traits/is_member_pointer.hpp Line 000056 "/home/jbrisbin/include/boost/type_traits/ is_member_pointer.hpp", line 56.63: CZP0403(30) "template <class T, class U> struct boost::is_member_pointer<U T::* const volatile>" ERROR 1 001 2 000051 The full text of the error complains that these are already defined. Does anyone have pointers or tricks that could point me in the right direction to compile programs that use header-only Boost libs on the AS400? Any help would be appreciated! :) Jon Brisbin Portal Webmaster NPC International, Inc.

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[PBGL] and [MTGL]
by Cosimo Calabrese 21 Sep '09

21 Sep '09

Hi to all, I open this discussion as a "branch" of "[BGL] Multithread problem inserting edges and exploring the same graph". Can someone tell me if the PBGL and MTGL can help me? I report my problem below, for sake of comfort. Thanks in advance, Cosimo Calabrese. ************************************************** I've a problem on BGL. My environment is WinXP, Visual Studio 2005, Boost 1.37. I'm trying to use BGL in the following way. I've a single graph in my application, that is an adjacency_list< vecS, vecS, ... >, and I've 2 kind of threads that work on the graph: - some "Explorer" threads, that executes a Dijkstra's algorithm repeatedly; - some "Integrator" thread, that call the add_edge() function repeatedly. The program often crashes, because it cannot dereference some graph elements, some auto_ptr... The crash isn't sistematic, so I think there's a concurrency problem. [...] **************************************************

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Python 3 support has landed on boost trunk
by Stefan Seefeld 21 Sep '09

21 Sep '09

Hi there, as some of you may know, Haoyu Bai has worked over the summer on Python 3 support for Boost.Python. This work happened on a branch, which I merged back into trunk last night. Now we need to set up testers to run the testsuite with some Python 3 variant, as that is a new platform to track. I will see whether I can set one up on one of my machines. Regards, Stefan -- ...ich hab' noch einen Koffer in Berlin...

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[filesystem] Compatibility with STLPort
by Andrey Semashev 21 Sep '09

21 Sep '09

Hi, I've created ticket #3241 some time ago, with a patch attached. It's about Boost.Filesystem compatibility with STLPort expression templates feature. So far no activity has appeared on it, although the fix is trivial. Is it OK if I go ahead and commit the patch? PS: Ticket URL is https://svn.boost.org/trac/boost/ticket/3241

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unsigned long vs unsigned int vs std::size_t (32b platform)
by Christoph Mathys 21 Sep '09

21 Sep '09

Hello! First: I'm working on 32b Linux (gcc 4.2.4) and 32b XP (Visual Studio 9 SP1). I tried to switch from stdint.h to boost/cstdint.hpp, but had to find out that this is not as straight forward as I thought. The compilers handle 'unsigned int' and 'unsigned long' as different types, even though on 32b it is AFAIK the same type. This by itself is OK, but gcc and VS9 seem to disagree in where it comes to defining std::size_t. The result is that the code at the end compiles on visual studio, but not on gcc: asdf.cpp: In function ‘void someFunc(size_t)’: asdf.cpp:6: error: redefinition of ‘void someFunc(size_t)’ asdf.cpp:5: error: ‘void someFunc(uint32_t)’ previously defined here asdf.cpp: In function ‘int main(int, char**)’: asdf.cpp:16: error: call of overloaded ‘someFunc(long unsigned int&)’ is ambiguous asdf.cpp:4: note: candidates are: void someFunc(uint16_t) asdf.cpp:5: note: void someFunc(uint32_t) In the stdint.h we used for visual studio previously, this error did not occur because uint32_t was typedefd to 'unsigned __int32'. Now, the questions are: - should boost::uint32_t be typedefed to the same thing that std::size_t is on 32b platforms? - Is the size of std::size_t fixed or dependant on the platform it is used on? - Did I do something wrong and there is a much better way of doing it avoiding those problems in the first place? #include <boost/static_assert.hpp> #include <boost/cstdint.hpp> void someFunc(boost::uint16_t) { } void someFunc(boost::uint32_t) { } void someFunc(std::size_t) { } int main(int, char**) { BOOST_STATIC_ASSERT(sizeof (unsigned long) == sizeof (unsigned int)); BOOST_STATIC_ASSERT(sizeof (unsigned long) == sizeof (std::size_t)); unsigned long ul = 42; unsigned int ui = 1337; std::size_t st = 2; someFunc(ul); someFunc(ui); someFunc(st); return 0; }

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