August 2010 - Boost-users - lists.preview.boost.org

[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

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[statechart] Passing parameters from event to State Local Storage
by Christophe Bourez 16 Nov '16

16 Nov '16

I need to maintain a parameter into the state local storage. This parameter is initially contained in the event that causes the transition to the target state. I give hereafter a small illustrative example. typename sc = boost::statechart; class EvTest : public sc::event<EvTest> { public: EvTest(std::size_t val) : value(val) {} std::size_t getValue() const { return this->value; } private: std::size_t value; }; class MyStateMachine; class StSource; class StTarget; class StSource : public sc::simple_state<StSource, MyStateMachine> { public: typedef sc::custom_reaction<EvTest> reactions; sc::result react(const EvTest &event) { // How to pass event.getValue() to the target state ? transit<StTarget>(); } }; class StTarget : public sc::simple_state<StTarget, MyStateMachine> { public: StTarget(std::size_t val) : val(value) {} private: std::size_t value; }; Thanks, Christophe

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Statechart serialization
by mbrodeur65 04 Mar '15

04 Mar '15

Hi, I'm looking for a solution to serialize boost::statechart objects. I'm aware that this feature is on the statechart library todo list but was wondering if there are any workaround to achieve this with the latest boost release (1.34) ? thanks for your help ! mbrodeur65 -- View this message in context: http://www.nabble.com/Statechart-serialization-tf4131326.html#a11749139 Sent from the Boost - Users mailing list archive at Nabble.com.

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[Statechart] How to decide between post_event and process_event atrun time ?
by Philippe DAVID 22 Jul '14

22 Jul '14

Hi, I have a method in which I want to post/process an event. The thing is, this method can be called from outside the state machine (so I need to call process_event), or indirectly by a reaction of the state machine (in this case I must call post_event since process_event is not reentrant). I don't want to write 2 distinct methods to do this (one that calls post, and the other process), I would much rather prefer adding a 'if' in my method that tells me if I have to call process_event or post_event (if I'm being called indirectly by the state machine or not). Is there a way to do this with statechart ? regards, Philippe

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[asio] resolver::cancel() problem
by Matthew Edwards 14 Mar '14

14 Mar '14

In my application (and a separate test program) it seems as though the cancel() function on the resolver does not work as intended. For async resolves, the cancel functionality should abort them immediately and pass an 'operation aborted' error code to the callback handler. In my tests, I will resolve an invalid domain (this causes the resolve to take a few seconds, to demonstrate the problem), sleep for 100ms, then call cancel on the resolver object. No cancelling actually occurs, and the callback is simply triggered after a few seconds with a "No host found" error code, not the expected operation aborted. Has anyone experienced this before, or know how I might be using the resolver incorrectly?

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[BGL] Having a cost function as weight map
by Maxime van Noppen 06 Sep '13

06 Sep '13

Hi, I can't find how to do this pretty basic thing : having a function instead of a field to compute the cost of edges for various path finding algorithms. I couldn't find the answer in the documentation and Google was of no help. Did I miss something obvious ? Example : ------------------- #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> struct my_edge { double cost() const { return cost_ * 2; } double cost_; }; struct my_node { }; int main() { typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS, my_node, my_edge > graph_t; typedef boost::graph_traits<graph_t>::vertex_descriptor vertex_t; graph_t graph; vertex_t v /*= ... */; using boost::weight_map; // Works : boost::dijkstra_shortest_paths(graph, v, weight_map(boost::get(&my_edge::cost_, graph))); // Doesn't compile : //boost::dijkstra_shortest_paths(graph, v, // weight_map(boost::get(&my_edge::cost, graph))); } ------------------- Thanks ! -- Maxime

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can't get first example in boost tutorial to work
by 7stud 11 Mar '13

11 Mar '13

I'm trying to install boost on mac osx 10.4.7. I followed the tutorial "Getting Started on Unix Variants" found here: http://www.boost.org/doc/libs/1_35_0/ more/getting_started/unix-variants.html Following the instructions in the tutorial, I installed boost in /usr/local as instructed, so my directory structure is: /usr/local/boost_1_34_1/boost But when I run the first example in the tutorial: #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each(in(std::cin), in(), std::cout << (_1 * 3) << " " ); } I get the error(among others): error: boost/lambda/lambda.hpp: No such file or directory If I change the include path to: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> I get the error(among others): error: boost/lambda/core.hpp: No such file or directory But core.hpp is in the lambda directory: /usr/local/boost_1_34_1/boost/lambda$ ls algorithm.hpp control_structures.hpp lambda.hpp bind.hpp core.hpp loops.hpp casts.hpp detail numeric.hpp closures.hpp exceptions.hpp switch.hpp construct.hpp if.hpp I'm using the Xcode 2.4 IDE to run my C++ programs. I also tried to execute the program from the command line with the original include path: #include <boost/lambda/lambda.hpp> but I get the same error: ~/2testing/dir1$ g++ prog1.cpp prog1.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope I get the same errors again with the full include path: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> $ g++ prog1.cpp In file included from prog1.cpp:1: /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:14:33: error: boost/lambda/core.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:21:52: error: boost/lambda/detail/operator_actions.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:22:61: error: boost/lambda/detail/operator_lambda_func_base.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:23:63: error: boost/lambda/detail/operator_return_type_traits.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:26:45: error: boost/lambda/detail/operators.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:30:46: error: boost/lambda/detail/member_ptr.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope What path should I be using? Or, should I set an environment variable somewhere?

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Re: [Boost-users] asio HTTP Server 3 example memory leak
by admin＠thefireflyproject.us 25 Aug '12

25 Aug '12

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[multi_array] operator= requires resize - why?
by Markus Werle 04 Jun '12

04 Jun '12

Hi! IMHO the behaviour of operator= for multi_array is a little bit broken. A lot of preconditions required: template <typename ConstMultiArray> multi_array_ref& operator=(const ConstMultiArray& other) { [...] // make sure the dimensions agree assert(other.num_dimensions() == this->num_dimensions()); assert(std::equal(other.shape(),other.shape()+this->num_dimensions(), this->shape())); Besides the fact that I get mad about asserts instead of exceptions (please change this to a way users may choose) why do we have such an odd behaviour here? >From page 1, line 3 of the docs I cite: "The interface design is in line with the precedent set by the C++ Standard Library containers" - this is not true for operator=, since std::<container>::operator= works fine for me all the time _without_ any resize. Could we please change the behaviour of multi_array::operator= to take care of resize where in need to? IMHO operator= should result in a true copy ignoring previous state. Markus

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MSVC Visualizers Update
by Filip Konvička 28 Jul '11

28 Jul '11

Hi all, I've just updated the Boost visualizers wiki page at https://svn.boost.org/trac/boost/wiki/DebuggerVisualizers I updated the visualizer for Boost.MultiIndex, which did not work since Boost 1.35. I also added new visualizers for Boost.DateTime (ptime and time_duration) and a simple boost::shared_ptr visualizer. The visualizers are available for checkout via SVN at https://svn.boost.org/svn/boost/sandbox/boost_docs/subprojects/DebuggerVisu… Cheers, Filip

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Asio unhandled exception
by Łukasz Majewski 20 May '11

20 May '11

Hello, I created a server single thread async (linux) and clinet (win). Every time client is close while server is writing to the socket connected to this client exception appears: terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::system::system_error>>' what(): Transport endpoint is not connected Aborted and server is terminated. I dont know why this exception is unhandled. int main( int argc, char** argv ) { try { boost::asio::io_service io_service; quotation_server server( io_service ); while ( true ) { try { io_service.run(); } catch( ... ){} } } catch ( std::exception& e ) { LOG << e.what() << std::endl; } catch( ... ) { LOG << "Unexpected exception" << std::endl; } return 0; }

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vs 2010 can't find correct boost lib version?
by Li, Tieniu 30 Mar '11

30 Mar '11

I built boost with visual studio 2010. Libraries of *-vc100-* are generated correctly. When trying to using boost.thread, VS 2010 generated error message: can't find *-vc90-*.lib. Any idea and fixing? Thanks a lot.

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[BGL] Separating twin vertices
by Shaun Jackman 19 Mar '11

19 Mar '11

Hi, I have a directed graph where every vertex has a twin vertex. It is known ahead of time which pairs of vertices are twins. I want to remove as few vertices as possible from the graph such that no vertex and its twin is in the same connected component. Could someone suggest an appropriate algorithm? I've just started delving into the BGL. So far I'm suitably impressed! Cheers, Shaun

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Simple serial port demonstration with boost asio asynchronous I/O
by Jeff Gray 26 Jan '11

26 Jan '11

A couple of weeks ago I posted a simple asynchronous demonstration of a telnet client using boost asio TCP network code. I have changed this code to turn it into a simple serial terminal application using the serial port support in the new version of boost asio. It required no changes at all the the read or write code. I just altered the initialization to use a serial port instead of a socket. Note that this is not intended to show how a fully functional application would work. There are plenty of areas that are not handled in this code. But it shows the idea and it's easy to build on this once you've got it working. Hope this helps someone else get started... Jeff

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[units] subtract_typeof_helper<> help!
by Terry Golubiewski 04 Jan '11

04 Jan '11

I'm trying to use boost::geometry and boost::units together. For some reason boost::geometry doesn't represent the difference of two points as vectors. So, I'm making my own Vector class and defining Vector = Point - Point. The sample program below doesn't compile because I need to tell the units library about the special properties of point subtraction (I think). terry #include <boost/geometry/geometry.hpp> #include <boost/units/systems/si.hpp> #include <boost/units/quantity.hpp> #include <boost/units/io.hpp> #include <iostream> #include <iomanip> using namespace std; using namespace boost; using namespace boost::geometry; using namespace boost::units; typedef point<double, 3, cs::cartesian> Point; class Vector { Point _impl; friend Vector operator-(const Point& lhs, const Point& rhs); explicit Vector(Point p) : _impl(p) { } public: Vector() : _impl(0) { } Vector(double dx, double dy, double dz=0) : _impl(dx, dy, dz) { } friend ostream& operator<<(ostream& os, const Vector& v) { return os << dsv(v._impl); } }; // Vector inline Vector operator-(const Point& lhs, const Point& rhs) { Point tmp(lhs); subtract_point(tmp, rhs); return Vector(tmp); } inline ostream& operator<<(ostream& os, const Point& pt) { return os << dsv(pt); } int main() { Point p1(1, 2, 3); Point p2(4, 5, 6); typedef quantity<si::length, Point> Position; typedef quantity<si::length, Vector> Displacement; Position start( p1 * si::meters); Position finish(p2 * si::meters); Displacement disp(finish - start); cout << "disp=" << disp << endl; return EXIT_SUCCESS; } // main

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[statechart] optional<event> - warning
by Igor R 07 Dec '10

07 Dec '10

Hello, When I define optional<my_event>, I get a warning (MSVC10): warning C4291: 'void *boost::statechart::event<MostDerived>::operator new(size_t,void *)' : no matching operator delete found; memory will not be freed if initialization throws an exception In class statechart::event I see 2 overloads of operator new: void * operator new( std::size_t size ) void * operator new( std::size_t, void * p ) But only 1 operator delete: void operator delete( void * pEvent ) i.e., no placement delete. Is this intentional? Thanks.

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[Program Options] Positional args in help message
by Lindley M French 10 Nov '10

10 Nov '10

The examples for how to use positional arguments are great and seem to work fine. However, I'm wondering if there's an automatic way to include that information in the help message. In particular, since the tutorial goes to the trouble of telling you how to exclude the positional options from the options help, it would be nice to know what to replace it with. I could manually write a line detailing the usage before outputting the options description, of course, but I was wondering if there was anything in PO to handle this automatically.

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[Asio]What's the behavior of socket.async_write() after socket.close() is called?
by 鑫炜廖 05 Nov '10

05 Nov '10

Hi, If I call socket.close() but I still have some data in my buffer, can I call async_write() later? When I call socket.close(), maybe an async_write operation is running, when it's complete I want to send data in another buffer(data written while previous async_write() is running, before socket.close() was called), but the socket is closed.Does it work in this situation?If not, what's the alternative way? The code looks like this: char front_buffer[kBufferSize]; char back_buffer[kBufferSize]; void HandleWrite(...) { //socket is closed. Does this work? socket.async_write(back_buffer, ...); } socket.async_write(front_buffer, HandleWrite); // write data to back_buffer socket.close();

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Polymorphic serialization with polymorphic archives problems... [part 2]
by Bogdan 03 Nov '10

03 Nov '10

First I would like to confirm I tested Robert Ramey's fix (@60273) for multiple registrations and it looks good in my runs. Thank you Robert! On the other hand, I am under the impression there is a bug in void_caster::recursive_unregister(), although I am not 100% certain about the reason: that function member is called in the destructors of the void caster template classes and makes use of the void_caster_registry singleton (more specifically the type_set). I believe it searches the set for all the void caster entries that are descendants of the current one (i.e., the one being destroyed) and performs the following ops: - delete the shortcuts. - remove the corresponding entries from the set. However, void_caster::recursive_unregister() DOESN'T REMOVE FROM THE REGISTRAR the entry corresponding to the current void_caster(). This creates the problem below: consider a scenario where a dll containing some serialization functionality is loaded explicitly at runtime (i.e., using LoadLibrary() on Windows or dlopen on Unix). There are no parent-child relationships among the serialized classes registered by that DLL: all serialized classes are derived from one abstract base. While unloading the library, its void_caster singletons are destroyed but there are no shortcuts to remove from the global registrar since there are no parent-child relationships. All entries corresponding to those are still in the global registrar and POINT TO THE void_caster SINGLETONS ALREADY DESTROYED AND DISCARDED. When the main process exits, the registrar traversal repeats for whatever process-bound void_caster singletons are about to be destroyed. During these subsequent traversals, void_caster::recursive_unregister() visits the entries left after the previous explicit dll download and tries to identify the parent-child relationship. In doing so, it accesses the dangling vc pointers generating access violations: void_cast.cpp(Line 286): const void_caster * vc = *it; void_cast.cpp(Line 287): if(vc->m_parent == this){ //<--------------------- here is the access violation I can reproduce the crash systematically, but I am not sure about the reason or whether a simple unregistration is enough. I believe this is (again) a question for Robert, but I thank for any feedback I might get. Bogdan

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[Boost.MPI] question about serializing custom object
by Cristobal Navarro 16 Oct '10

16 Oct '10

hello everybody, this is first post i have some questions after reading the Boost documentation of serialization and MPI, is it possible to serialize my custom objects with Boost.serialize and then send/receive them using plain openMPI as MPI_BYTE type?? the other question is on the tutorials i only found examples of serializing objects to archive and saving to file, but i didnt find any example where they serialize it to a binary form and send them through mpi, is there any example of this type on the documentation? best regards Cristobal

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upgrade_to_unique_lock doesn't compile with vc2010
by Braden McDaniel 16 Sep '10

16 Sep '10

Using Boost 1.43, this program: # include <boost/thread.hpp> int main() { boost::shared_mutex mutex; boost::upgrade_lock<boost::shared_mutex> lock(mutex); boost::upgrade_to_unique_lock<boost::shared_mutex> write_lock(lock); } ... produces this error when compiled with Visual C++ 2010: C:\Users\braden>cl /I include/boost-1_43 /MD /EHsc upgrade_to_unique_lock_test.cpp Microsoft (R) C/C++ Optimizing Compiler Version 16.00.30319.01 for x64 Copyright (C) Microsoft Corporation. All rights reserved. upgrade_to_unique_lock_test.cpp include/boost-1_43\boost/thread/locks.hpp(823) : error C2679: binary '=' : no operator found which takes a right-hand operand of type 'boost::unique_lock<Mutex>' (or there is no acceptable conversion) with [ Mutex=boost::shared_mutex ] include/boost-1_43\boost/thread/locks.hpp(659): could be 'boost::upgrade_lock<Mutex> &boost::upgrade_lock<Mutex>::operator =(boost::upgrade_lock<Mutex>&)' with [ Mutex=boost::shared_mutex ] include/boost-1_43\boost/thread/locks.hpp(710): or 'boost::upgrade_lock<Mutex> &boost::upgrade_lock<Mutex>::operator =(boost::detail::thread_move_t<T>)' with [ Mutex=boost::shared_mutex, T=boost::upgrade_lock<boost::shared_mutex> ] include/boost-1_43\boost/thread/locks.hpp(717): or 'boost::upgrade_lock<Mutex> &boost::upgrade_lock<Mutex>::operator =(boost::detail::thread_move_t<T>)' with [ Mutex=boost::shared_mutex, T=boost::unique_lock<boost::shared_mutex> ] while trying to match the argument list '(boost::upgrade_lock<Mutex>, boost::unique_lock<Mutex>)' with [ Mutex=boost::shared_mutex ] include/boost-1_43\boost/thread/locks.hpp(820) : while compiling class template member function 'boost::upgrade_to_unique_lock<Mutex>::~upgrade_to_unique_lock(void)' with [ Mutex=boost::shared_mutex ] upgrade_to_unique_lock_test.cpp(7) : see reference to class template instantiation 'boost::upgrade_to_unique_lock<Mutex>' being compiled with [ Mutex=boost::shared_mutex ] I've searched a bit for previous reports of this sort of thing and I haven't found any. Hopefully that means I'm just doing something wrong. -- Braden McDaniel <braden(a)endoframe.com>

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Help with shared_ptr and template
by Mario Chacon 10 Sep '10

10 Sep '10

Hello: I have this problem and I do not how to fix it, I know I cannot write template typedefs, its a limitiation of the C++ syntax, right? or I'm wrong? I saw that the best way is to wrap your typedefs in a struct, which can be templated, but I'm still stack with problems. The best way to explain it's with an example: #include <cstdlib> #include <iostream> #include <boost/shared_ptr.hpp> template< typename tvalue > class CValue { public: CValue( tvalue value ) : value_(value) {}; private: tvalue value_; }; template< typename tvalue > struct Type{ typedef boost::shared_ptr< CValue< tvalue > > pValue; }; int main(int argc, char *argv[]) { Type<bool>::pValue a; return EXIT_SUCCESS; } How can I create a shared_ptr for the template class "CVALUE"?? Please I do not know what else I can prove... :( Thank you.. Mario.. Salu2...

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[test] Windows Vista: "The application failed to initialize properly (0xc0000005)."
by Daniel Trebbien 09 Sep '10

09 Sep '10

I am using MinGW on Windows to try to compile a working shared binary of Unit Test Framework. My GCC version is the latest for MinGW, 4.5.0, and I used the following line to compile libboost_unit_test_framework-mgw45-mt-1_44.dll: bjam toolset=gcc link=shared --with-test release I have tried both Boost 1.43.0 and 1.44.0 beta 1 sources, but with each, bjam succeeds and my test program that uses UTF fails with the message dialog: The application failed to initialize properly (0xc0000005). Click OK to terminate the application. My test program compiles and runs fine on Debian Linux using Boost 1.42. Is anyone else experiencing this problem?

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Building Boost on Mac Snow Leopard
by Andrew Maclean 08 Sep '10

08 Sep '10

Hi All, If I build boost using bjam (no problems there) and set in .bashrc: export DYLD_LIBRARY_PATH="$DYLD_LIBRARY_PATH:${BOOST_ROOT}/stage/lib" Things seem to work OK when when calling applications from the command line in a terminal. However if I invoke the application e.g. x.app from the Finder the boost dynamic libraries are not found. If I run for example, otool -D /Users/andrewmaclean/Code/GeneralLibraries/boost_1_44_0/stage/lib/libboost_date_time.dylib /Users/andrewmaclean/Code/GeneralLibraries/boost_1_44_0/stage/lib/libboost_date_time.dylib: libboost_date_time.dylib Clearly no absolute path is set. It seems to me that Finder is ignoring the DYLD_LIBRARY_PATH variable, I even changed it to DYLD_FALLBACK_LIBRARY_PATH to see if it would make any difference. So the only solution I have is to install boost into the default system libraries, where it works perfectly. Now comes the interesting question. If I build VTK then the absolute paths are put into the dynamic libraries. So something in CMake/gcc actually adds these paths into the dynamic libraries. Why doesn't bjam do this? Is there a parameter I am missing? Rgeards Andrew -- ___________________________________________ Andrew J. P. Maclean Centre for Autonomous Systems The Rose Street Building J04 The University of Sydney 2006 NSW AUSTRALIA Ph: +61 2 9351 3283 Fax: +61 2 9351 7474 URL: http://www.acfr.usyd.edu.au/ ___________________________________________

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How to store on exception object ?
by Timothy Madden 07 Sep '10

07 Sep '10

Hello In a callback function I need to store and save an exception object for until the callback is finished and the control is returned to my application code. The callback is invoked by the C language code in minizip library from zlib-1.2.3 contrib directory, and I need to throw the exception when control returns to my application invoking minizip functions. This is true for any exception that might get thrown and caught in my callback, so I would like to do that for any exception type. However how can I store a thrown object for later re-throw without the actual exception type ? Is there a way to do that ? Thank you, Timothy Madden

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