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

Re: [Boost-users] Turn off versioning in Serialization
by Brian Nantz 03 Dec '08

03 Dec '08

Robert, Thanks for the quick reply. I was able to turn all the headers off but there is still one number (which seems to be thre string length) that I can not turn off. If this is unable to be turned off then I will proceed to the Case Study you mentioned. Brian Brian Nantz wrote: > I am using serialization split member (save & load) and it works > great. I am using a text archive, but I do not want the framework to > put the "version header" in the string (e.g. 22 > serialization::archive 4 1303 ). This is the serialization library version. When you create the archive you can specify the flag no_header to suppress it. I want to simply serialize the > string and handle the versioning myself in the load function. Is > there a way to turn this off? THis sounds like your talking about class version - which is different from the above. this can be suppressed on a class by class basis. in the documentation Reference Serializable Concept Class Serialization Traits Implementation level. > If not, where can I find detailed documentation on implementing a > custom archive or build in another type of serialization (other than > binary and xml nvp)? I have looked through mailing lists and > documentation but I don't see a detailed description of how to extend > the design. Try looking at Case Studies Derivation from an existing archive cass > > Brian Robert Ramey

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Problem on Boost using stlport4 on Sun C++
by a_disabatino 03 Dec '08

03 Dec '08

Hi everybody, please help me, I tried to use boost 1.34.1 and 1.36.0 same problems, I got this error: 1/boost/array.hpp", line 75: Error: Too few arguments for template std::reverse_iterator<boost::T*>. boost/boost_1_34_1/boost/array.hpp", line 289: Where: While specializing "boost::array<boost::T, boost::N>". boost/boost_1_34_1/boost/array.hpp", line 289: Where: Specialized in non-template code. /boost/boost_1_34_1/boost/array.hpp", line 76: Error: Too few arguments for template std::reverse_iterator<const boost::T*>. boost/boost_1_34_1/boost/array.hpp", line 289: Where: While specializing "boost::array<boost::T, boost::N>". boost/boost_1_34_1/boost/array.hpp", line 289: Where: Specialized in non-template code. "/opt/SUNWspro/prod/include/CC/Cstd/./iosfwd", line 148: Information: Library has instance std::ostringstream::basic_ostringstream(int). "/opt/SUNWspro/prod/include/CC/Cstd/./ostream", line 471: Information: Library has instance std::operator<<(std::ostream &, const char*). "/opt/SUNWspro/prod/include/CC/Cstd/./iosfwd", line 145: Information: Library has instance std::ostream::operator<<(unsigned). "/opt/SUNWspro/prod/include/CC/Cstd/./iosfwd", line 148: Information: Library has instance std::ostringstream::str() const. "/opt/SUNWspro/prod/include/CC/Cstd/./string", line 858: Information: Library has instance std::string::basic_string(const char*, const std::allocator<char>&). if I compile Boost using the flag -library=stlport4 i was able to solve that problem, but my applications uses libCstd Sun standard library since when I tried to link the library into my application I got core. So I'd like to compile boost just using libCstd I mean sun implementation. do you have some suggests on thi issue please? you welcome Tony

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Re: [Boost-users] [review][constrained_value] Review of Constrained Value Library begins today
by Jesse Perla 03 Dec '08

03 Dec '08

As someone who was about to try to write something similar out of necessity, let me throw out a few practical considerations and a use case. These are a wish list from a library user that is not a generic library programmer: What I really want is to have a "type" that contains bounds information, rather than for bounds checking itself (which is gravy). And I want to use this for pretty functional programming, and see this as an incredibly useful library and integral to taking C++ to the next level for programming mathematics. I do not see this as primarily an equivalence to units, though I understand that use case. My primary cases for this are: 1. For functors that contain domain/range sets to match the blackboard mathematics I am implementing in code. Including "operators" that map functors to functors (my main case being a derivative operator or a conditional expectation). 2. To use this an optimizer framework. The problem is that you end up having to keep around lists of reasonable bounds on what values the optimizer should be allowed to use. But this information becomes separated from the real "type" of the variable, even though that is where it conceptually belongs. And when you call optimizers you need to have both. Of course, this optimizer/root finder problem is really the same issue as maintaining range/domain for functors. So a few comments on what I would love to be able to do to support this: 1. The closed/open bounds in here is necessary, especially for optimizers where you frequently have asymptotes at the bounds (virtually always in the dynamic programming for economics problems I work with). 2. I would go further than saying that the closed/open bounds is a starting point and that the library should ultimately be designed to accomodate (runtime) unions of intervals and discrete points i.e. [x,x] in intervals. This would be very useful for game theory applications where you could get non-connected sets of equilibrium conditions. Or functions where you can have asymptotes in the middle that are not defined, but it is defined on both sides. Last, would be nice to allow for a discrete set of real values as bounds. If the design of the library could support this (maybe by returning an iterator over the ranges if necessary?) then it could be implemented later. Keep in mind that my need is to access/set the bounds at runtime rather than just boundschecking by writing my own bounds checking predicate. 3. Turning off the bounds-checking at runtime could be useful (though certinaly not through NDEBUG!), but you would NEVER want to turn off the availability of the bounds information at runtime since that is the core usefulness of the library. 4. If it is true in general, then this statement: http://student.agh.edu.pl/~kawulak/constrained_value/constrained_value/rati… makes this library practically useless. I understand the rationale, but since all optimizers take floats or doubles, and 99% of functions map doubles to doubles for me, this is an unreasonable constraint. If the problem here is just for the bounds checking, then I am not worried since I really want type information. 5. Sometimes you want to have compile-time fixed bounds , other times modifiable at runtime. So I like this, but they need to behave the same way. But what I really want to do is change the bounds of the type itself at runtime, not just the bounds on an individual instantiation. See the following to see if I am misundertanding the library: typedef bounded<double> interest_rate; interest_rate r1, r2; change_bounds(r1, .8, .99); Now the interest rate bounds on r2 don't exist, right? This is a big problem for me... It would mean that the bounds information is not kept on the type, but on the instantiation... this has extra data and has completely different semantics from the static bounds case where it really is associated with the type. What I would really want is some kind of static data associated with the type. I understand the difficulty here, but nevertheless this is the main usefulness of the library. I also note that this means the "typedef" approach may be a problem as it is set up since the library would have no way to tell the difference between these types to store static bounds, even though this is exactly what I want.: typedef bounded<double> interest_rate; typedef bounded<double> risk_aversion; interest_rate r; risk_aversion crra ; change_bounds(r, .8. .99); //Storing this statically change_bounds(crra, 1.0, 10.0); //Statically. interest_rate r_guess; //Want the right bounds! Can't exist here? Of course, with static bounds this kind of thing works. Perhaps it is reasonable to throw in some sort of useless trick for the compiler to separate when storing static data to keep semantics with the static bounds the same? I don't know if this is a good approach, but it would be reasonable to ask of library users: typedef bounded<double, "INTEREST RATE"> interest_rate; //In fact, I wouldn't even mind having the "name" available at runtime for pretty_printing... typedef bounded<double, "RISK_AVERSION"> risk_aversion; interest_rate r; risk_aversion crra ; change_bounds(r, .8. .99); //Storing this statically, now the two types are distinct? change_bounds(crra, .5, 10); //Statically. interest_rate r_guess; //Want the right bounds. Naturally, there are other cases where you might want to change the bounds on an instantiation. If both could be supported (and returned through the same bounds function, modified through different ones) that would be nice, but the above use case is far more important to me. 6) Is there any way to get the library to compile: std::max(2, i) instead of using i.value() as mentioned in the tutorial for a constrained i? This really is essential to make the library equivalent to normal operations, but with extra type information. Again, I am willing to forgo ease of use on the bounds checking for this... What I really want is the instantiation to behave EXACTLY the same as an underlying type. So overloading the ++, +, etc. are useful, but I would go further to say that perhaps everything could be done by just going back to the underlying type... with abolutely no overhead since it would make this useless for numeric programming. If I multiply or add these kinds of values, I would want the result to be of the underlying type and don't care about the mechanics of ensuring that the result type is bounded itself, etc. I can construct my own bounded type for the return type if I have to... Thanks for listening. And if people have better ideas of a framework or approach to do this kind of stuff, please tell me. I may be stretching the expectations of this library... -Jesse

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[Thread] barrier destruction after wait() results in assertion
by Peter Klotz 03 Dec '08

03 Dec '08

Boost 1.37.0, Red Hat Enterprise Linux 5 x86_64, gcc 4.1: The following simple test establishes a barrier with thread count 2. One of the threads destroys the barrier after returning from wait(). This results in sporadic assertions from ~mutex(). boost/thread/pthread/mutex.hpp:45: boost::mutex::~mutex(): Assertion `!pthread_mutex_destroy(&m)' failed. #1 0x00000038306295d6 in __assert_fail () from /lib64/libc.so.6 #2 0x000000000040245a in ~mutex (this=0x1f63f010) at boost/thread/pthread/mutex.hpp:45 #3 0x0000000000402488 in ~barrier (this=0x1f63f010) at boost/thread/barrier.hpp:24 I assume that this usage of barrier is not supported/allowed. One cannot assume that the barrier can be destroyed just because the corresponding thread returned from wait(). Is this conclusion correct? Regards, Peter. #include <boost/scoped_ptr.hpp> #include <boost/thread/barrier.hpp> #include <boost/thread/thread.hpp> boost::scoped_ptr<boost::barrier> barrier; void f() { barrier->wait(); } int main(void) { barrier.reset(new boost::barrier(2)); boost::thread thread(boost::bind(&f)); barrier->wait(); barrier.reset(); thread.join(); return 0; }

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Threads - Access in invalid memory Boost 1.36.0 BCB 5.8.3
by Stephen Kierzewski 03 Dec '08

03 Dec '08

Hello, I have a simple OpenGL program that is using Boost Threads and I had it working fine under Boost 1.34. I have switched to 1.36 for some of the newer mutex locking functionality and everything works fine, but.. I keep getting an invalid memory access error. My program will run fine if i skip past the offending call. Wondering if anyone has any ideas? The offending call happens when the rendering thread is created. The call stack is as follows: Access in invalid memory in process: solarsystemT.exe(4056) - :\development\boost_1_36_0\boost/thread/win32/once.hpp#125 Attempt to access 4 byte(s) at 0x00417084. 0x00411056 - E:\development\boost_1_36_0\boost/thread/win32/once.hpp#125 0x0041137B - E:\development\boost_1_36_0\libs\thread\src\win32\thread.cpp#44 0x00411A61 - E:\development\boost_1_36_0\libs\thread\src\win32\thread.cpp#151 The memory that boost::call_once is accessing is current_thread_tls_init_flag created earlier by boost::once_flag current_thread_tls_init_flag=BOOST_ONCE_INIT; I can see that this flag was created and initialized to zero. Thank you for any insight. Stephen Kierzewski

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Boost.Build newbie
by frederic.bron＠alcan.com 03 Dec '08

03 Dec '08

I have read the documentation of boost.build on boost.org and I have a few questions: 1.) I do not understand what's more in boost.build compared to bjam; I see no reference to something else than bjam in boost.build doc. 2.) Is it true that the dependencies must be specified manually in a Jamfile; dependenceis are not automatically found with header files. I understood this from this page of the doc : http://www.boost.org/doc/tools/build/doc/html/bbv2/tutorial/libs.html However, the example is with a library dependency and not with source file dependecies. Today I use the makedepend utility and a bash script to build a valid Makefile. However, it is hard to maintain and I would like to add msvc compiler on windows and it causes me much trouble. Boost.build seems to do that but if I have to manually track the dependencies, I prefer to continue with gcc only. Regards, F. Bron Avis : Ce message et toute pièce jointe sont la propriété d'Alcan et sont destinés seulement aux personnes ou à l'entité à qui le message est adressé. Si vous avez reçu ce message par erreur, veuillez le détruire et en aviser l'expéditeur par courriel. Si vous n'êtes pas le destinataire du message, vous n'êtes pas autorisé à utiliser, à copier ou à divulguer le contenu du message ou ses pièces jointes en tout ou en partie. Notice: This message and any attachments are the property of Alcan and are intended solely for the named recipients or entity to whom this message is addressed. If you have received this message in error please inform the sender via e-mail and destroy the message. If you are not the intended recipient you are not allowed to use, copy or disclose the contents or attachments in whole or in part.

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how to work with shared pointers to avoid clumsiness
by Roman Shmelev 03 Dec '08

03 Dec '08

Hi, I've tried to read boost docs and some forums but still cannot understand how to make things simple and right. 1) I have an object that is dynamically allocated and I want it to delete itself (so I understood I need to use shared_ptr) 2) The object must be deleted not after the last shared_pointer to it will be destroyed, because some external functions will call it later one more time. And then it must be destroyed. 3) Of course, that external functions cannot accept shared_ptrs. 4) So, I need my object to know when all shared_ptrs to it are destroyed. Then it sets some flag (I_CAN_DESTROY_MYSELF_SOON) and when some external code (that holds simple pointer to this object) will call its function, then it will destroy itself. How to solve this in an elegant way? I'm currently do not use shared_ptr, but my implementation is cumbersome. Maybe I need one more shared_ptr inside the object.. I don't know. Thank you.

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[program_options]
by Vitaly Grechko 03 Dec '08

03 Dec '08

Could _WIN32 be removed from program_options\parsers.hpp? There is no way in UNIX to parse command line independently from string. To use the library I had to dublicate parsers.hpp and winmain.cpp files localy with _WIN32 removed, which is ugly. Before this I tryed to define _WIN32 before including parsers.hpp and undef after - this affected other boost headers and did not compile. I don't see the reason to have _WIN32 macro there because the code is just an algorithm and complied successfuly in all platforms. The meaning of the algorithm is in the name of the function 'split_winmain(...)'. The use case example: command lines from Windows client machines go to Unix server for validation and logging. In this case split_winmain is regularly used on UNIX Vitaly

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basic functions
by boost001 03 Dec '08

03 Dec '08

New to Boost, want to find the following basic functions, please tell me where to find them: 1. sleep function; 2. get current working directory; 3. get current system time; 4. get file separator or directory separator; thanks, -- View this message in context: http://www.nabble.com/basic-functions-tp20803583p20803583.html Sent from the Boost - Users mailing list archive at Nabble.com.

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Asio
by Cain 03 Dec '08

03 Dec '08

Hi, I'm making a program that has a GUI and i was planning on using Asio because of it's SSL support, i thought it was just simple callback structure etc but then i got told that io_service::run() blocks? i understand that would be fine in server applications but in this case the GUI would block. How would any of you use asio in my situation?

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