Hi, This is hard to debug remotely but here is the catch: - you have a shared datastructure that you have put into a local object. - you need to make sure that both propagator and brancher destruct the local handle but only if neither needs it any longer. If you make use of the local handle in both propagator as well as brancher then everything should be fine. - for the propagator it means you have to use the AP_DISPOSE thing as you did. In its dispose method you have to add an explicit call to the destructor of the local handle, say that the local object is names lo and of type Foo. Then lo.~Foo() will do the trick. - for the brancher you also have to call in its dispose method the destructor.
My guess is that the error comes from the fact that the shared object has already been destroyed by either propagator or brancher and the other still tries to access it. Cheers Christian -- Christian Schulte, www.gecode.org/~schulte Professor of Computer Science, KTH, cschu...@kth.se Expert Researcher, SICS, cschu...@sics.se -----Original Message----- From: users-boun...@gecode.org [mailto:users-boun...@gecode.org] On Behalf Of Peter Backeman Sent: Saturday, January 7, 2017 02:02 To: users@gecode.org Subject: [gecode-users] Using LocalHandles and LocalObjects with External Resources Hello, I've implemented a custom propagator and brancher which are sharing a data-structure (a matrix of values), To share the structure in an efficient (and convenient) way I have looked at using LocalHandle and LocalObject. In MPG (Sec 31.4, page 391) this is described how to be implemented, however I am doing something wrong because I keep on getting some kind of memory error. My main problem is with the notice for disposal (since external resources are used). If I do not use home.notice(*this, AP_DISPOSE) (line 17 in attached file), my program does run without errors, but I suspect it might lead to memory leaks. I've tried figuring out how this should work, but I have yet to find a full example using LocalHandle/LocalObject (i.e. together with a model) and no previous issues around this. I'm attaching a minimum failing example (main.cpp), I'm compiling it on ubuntu using g++ version 5.4.0. and Gecode version 5.0.0 (I'm fairly sure, do not know how to exactly check this) using the following command: g++ -g -o main src/main.cpp -lgecodedriver -lgecodegist -lgecodesearch -lgecodeminimodel -lgecodeint -lgecodekernel -lgecodesupport and when running it I receive the following error (gdb output): ---------------------------------------------------------------------------- - Program received signal SIGSEGV, Segmentation fault. Gecode::VarImp<Gecode::Int::IntVarImpConf>::update (sub=<synthetic pointer>, home=...) at ./gecode/kernel/core.hpp:4438 4438 ./gecode/kernel/core.hpp: No such file or directory. (gdb) where #0 Gecode::VarImp<Gecode::Int::IntVarImpConf>::update (sub=<synthetic pointer>, home=...) at ./gecode/kernel/core.hpp:4438 #1 Gecode::Space::update (sub=0x64e380, this=0x64e220) at ./gecode/kernel/var-imp.hpp:484 #2 Gecode::Space::_clone (this=0x63c6a0, share_data=share_data@entry=true, share_info=share_info@entry=true) at gecode/kernel/core.cpp:584 #3 0x00007ffff776b813 in Gecode::Space::clone (share_info=true, share_data=true, this=<optimized out>) at ./gecode/kernel/core.hpp:3262 #4 Gecode::Search::Sequential::BAB::next (this=0x64db38) at ./gecode/search/sequential/bab.hh:149 #5 Gecode::Search::WorkerToEngine<Gecode::Search::Sequential::BAB>::next (this=0x64db30) at ./gecode/search/support.hh:86 #6 0x0000000000411ad9 in Gecode::Search::Base<MyScript>::next (this=<optimized out>) at /usr/local/include/gecode/search/base.hpp:51 #7 Gecode::Driver::ScriptBase<Gecode::Driver::IgnoreStepOption<Gecode::IntMinim izeSpace> >::runMeta<MyScript, Gecode::BAB, Gecode::SizeOptions, Gecode::Driver::EngineToMeta> (o=..., s=0x63c6a0) at /usr/local/include/gecode/driver/script.hpp:360 #8 0x0000000000408e15 in Gecode::Driver::ScriptBase<Gecode::Driver::IgnoreStepOption<Gecode::IntMinim izeSpace> >::run<MyScript, Gecode::BAB, Gecode::SizeOptions> (o=..., s=0x0) at /usr/local/include/gecode/driver/script.hpp:274 #9 0x0000000000405536 in main (argc=1, argv=0x7fffffffe0d8) at src/main.cpp:63 ---------------------------------------------------------------------------- - Any ideas on what might be the problem is greatly appreciated. My guess is that perhaps the destructor of the LocalHandle (LH) class have to make sure dispose is called on the LocalObject (LHO), however my skills in C++ and Gecode are not enough to know how I can try this. If someone just have an implementation using LocalHandles/LocalObjects which is working, just letting me have a look on that would be very helpful! Best regards, Peter Backeman
smime.p7s
Description: S/MIME cryptographic signature
_______________________________________________ Gecode users mailing list users@gecode.org https://www.gecode.org/mailman/listinfo/gecode-users
