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[Boost.Python] C++/Python Hybrid App in 2020
by Andrew McFarlane 22 Feb '20

22 Feb '20

Hi all, I read on the Boost.Python FAQ that for Mac OSX users, the library is currently known only to work with the GCC compiler. Thus far, I have been using clang++. I will make the switch, so long that it does increase my odds of encountering difficulties down the road. What do we think here? In the context of front-end dev in Python for a C++ application, is Boost.Python worth making the switch from clang++ to gcc? Would I be better off using something else (i.e. wxPython)? I really love using Boost (I've found use for Test, Signals2, and Asio), but I don't want to let my Boost bias lead me to make a poor choice. I know this question is a tad subjective; I apologize for that. I would like the Python extension to be as seamless as possible, and I am only going to be using Python for front-end code. The interface between the two would likely be with sockets. I am sure I could answer this myself via experimentation, but I wanted to get a feel from the Boost community before doing so. Thanks in advance! *- AJ*

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Newbie Question Shared Memory Containers/Allocators
by Da Xu 14 Feb '20

14 Feb '20

Hi everybody, how are you? I am a completely noob when it comes to Boost. :D But not a noob when it comes to C++. Though, am a bit noobish when it comes to C++14 and beyond :D I am trying to construct a complex data container, which has a vector of floats, on managed shared memory. I followed the documentation, added the appropriate headers and made the following declarations: typedef managed_windows_shared_memory::segment_manager segment_manager_t; typedef allocator<void, segment_manager_t> void_allocator; typedef basic_string<char, std::char_traits<char>, char_allocator> shared_string; typedef allocator<float, segment_manager_t> float_allocator; typedef vector<float, float_allocator> float_vector; typedef allocator<float_vector, segment_manager_t> float_vector_allocator; class ComplexContainer {shared_string name;float_vector channelData; public:ComplexContainer(const char * name_, const float* data_start, const float* data_end, const void_allocator& void_alloc) : name(name_), channelData(data_start, data_end, void_alloc) {} ComplexContainer(const void_allocator& void_alloc) : name(void_alloc), channelData(void_alloc){} ComplexContainer() {} } but I am getting these errors at compile: 1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(310,23): error C2512: 'boost::interprocess::allocator<float,segment_manager_t>::allocator': no appropriate default constructor available1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(308): message : while compiling class template member function 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>::vector_alloc_holder(void) noexcept(false)'1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(832): message : see reference to function template instantiation 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>::vector_alloc_holder(void) noexcept(false)' being compiled1>D:\Libraries\boost_1_72_0\boost\container\vector.hpp(779): message : see reference to class template instantiation 'boost::container::vector_alloc_holder<boost::interprocess::allocator<float,segment_manager_t>,unsigned __int64,boost::move_detail::integral_constant<unsigned int,2>>' being compiled message : see reference to class template instantiation 'boost::container::vector<float,float_allocator,void>' being compiled That doesn't make a whole lot of sense, since it seems to be referring to the "float_allocator" typedef. But float is not an object, it has no constructor. Any help would be greatly appreciated! Thank you! Da.

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Re: [Boost-users] boost float128 and Intel's _Quad with Tux Eigen
by Alex.Durie 04 Feb '20

04 Feb '20

Thanks John, >The good news is that Intel on Linux does support GCC's __float128 type, >so my suggestion would be to: >* Remove the #define BOOST_MP_USE_QUAD >* Build with -std=gnu++14 rather than -std=c++14 >* Remove the -Qoption,cpp,--extended_float_type option. Unfortunately that didn't work, I get the new compiler error; /home/alex/boost/boost_1_71_0/boost/multiprecision/detail/number_base.hpp(216): error: static assertion failed with "is_integral<T>::value || is_enum<T>::value || std::numeric_limits<T>::is_specialized" BOOST_STATIC_ASSERT(is_integral<T>::value || is_enum<T>::value || std::numeric_limits<T>::is_specialized); Are you able to help? Many thanks, Alex ________________________________ From: Boost-users <boost-users-bounces(a)lists.boost.org> on behalf of boost-users-request(a)lists.boost.org <boost-users-request(a)lists.boost.org> Sent: 04 February 2020 10:56 To: boost-users(a)lists.boost.org <boost-users(a)lists.boost.org> Subject: Boost-users Digest, Vol 5318, Issue 1 CAUTION: This mail comes from outside the University. Please consider this before opening attachments, clicking links, or acting on the content. Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. boost float128 and Intel's _Quad with Tux Eigen (Alex.Durie) 2. [boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition? (Eko palypse) 3. Re: [boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition? (Mateusz Loskot) 4. Re: [boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition? (Eko palypse) 5. Re: boost float128 and Intel's _Quad with Tux Eigen (John Maddock) ---------------------------------------------------------------------- Message: 1 Date: Mon, 3 Feb 2020 21:33:13 +0000 From: Alex.Durie <alex.durie(a)open.ac.uk> To: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> Subject: [Boost-users] boost float128 and Intel's _Quad with Tux Eigen Message-ID: <CWLP265MB0244A9FE67071B7EE7C7E2BFA3000(a)CWLP265MB0244.GBRP265.PROD.OUTLOOK.COM> Content-Type: text/plain; charset="iso-8859-1" Hi, I have written a short program utilising boost::float128 together with tux Eigen which successfully compiles and runs using g++, however it fails when I use icc. The compiler error is /home/alex/boost/boost_1_71_0/boost/multiprecision/float128.hpp(727): error: no suitable constructor exists to convert from "const _Quad" to "boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>" static number_type (min)() BOOST_NOEXCEPT { return BOOST_MP_QUAD_MIN; } ^ How can I resolve this? My example code is; #include <iostream> #include <cmath> #include <Eigen/Dense> #include <Eigen/Eigenvalues> #include <iomanip> #include <boost/cstdfloat.hpp> #include <boost/multiprecision/float128.hpp> #include <boost/math/special_functions.hpp> #include <boost/math/constants/constants.hpp> #include <quadmath.h> #define BOOST_MP_USE_QUAD using namespace Eigen; using namespace std; int main(){ typedef Matrix<complex<boost::multiprecision::float128>, Dynamic, Dynamic> MatrixXcmp; MatrixXcmp C = MatrixXcmp::Random(8,8); cout<<setprecision(128)<<C<<endl<<endl; ComplexEigenSolver<MatrixXcmp> ces; ces.compute(C); return 0; } It only fails compilation when I put in the line 'ces.compute(C);'. I compile with icpc quadtest.cpp -std=c++14 -Qoption,cpp,--extended_float_type -O2 -DMKL_LP64 -lmkl_intel_lp64 -fp-model precise -lmkl_sequential -lmkl_core -lpthread -lm -ldl -lquadmath Many thanks in advance, Alex

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boost float128 and Intel's _Quad with Tux Eigen
by Alex.Durie 04 Feb '20

04 Feb '20

Hi, I have written a short program utilising boost::float128 together with tux Eigen which successfully compiles and runs using g++, however it fails when I use icc. The compiler error is /home/alex/boost/boost_1_71_0/boost/multiprecision/float128.hpp(727): error: no suitable constructor exists to convert from "const _Quad" to "boost::multiprecision::number<boost::multiprecision::backends::float128_backend, boost::multiprecision::et_off>" static number_type (min)() BOOST_NOEXCEPT { return BOOST_MP_QUAD_MIN; } ^ How can I resolve this? My example code is; #include <iostream> #include <cmath> #include <Eigen/Dense> #include <Eigen/Eigenvalues> #include <iomanip> #include <boost/cstdfloat.hpp> #include <boost/multiprecision/float128.hpp> #include <boost/math/special_functions.hpp> #include <boost/math/constants/constants.hpp> #include <quadmath.h> #define BOOST_MP_USE_QUAD using namespace Eigen; using namespace std; int main(){ typedef Matrix<complex<boost::multiprecision::float128>, Dynamic, Dynamic> MatrixXcmp; MatrixXcmp C = MatrixXcmp::Random(8,8); cout<<setprecision(128)<<C<<endl<<endl; ComplexEigenSolver<MatrixXcmp> ces; ces.compute(C); return 0; } It only fails compilation when I put in the line 'ces.compute(C);'. I compile with icpc quadtest.cpp -std=c++14 -Qoption,cpp,--extended_float_type -O2 -DMKL_LP64 -lmkl_intel_lp64 -fp-model precise -lmkl_sequential -lmkl_core -lpthread -lm -ldl -lquadmath Many thanks in advance, Alex

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[boost build] - How to create symbols (.pdb) files on windows using VS2017 Community Edition?
by Eko palypse 03 Feb '20

03 Feb '20

How can I build pdb files using b2 tool? If I run b2 -a --with-regex toolset=msvc-14.1 debug-symbols=on address-model=64 architecture=ia64 variant=debug it creates the needed lib but no pdb files are created. Thank you Eren

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Re: [Boost-users] Boost-users Digest, Vol 5315, Issue 1
by Andrew McFarlane 31 Jan '20

31 Jan '20

@Gavin @Edward: Success! The program is now executing as expected, *thanks to all of your helpful suggestions.* Here's what I did: 1. added --with-chrono to my b2 command, which placed .a and .dylib files for chrono in stage/lib. 2. after invoking the following compiler command: g++ -v -Wall -L ${BOOST_ROOT}/stage/lib -lboost_chrono -lboost_date_time -lboost_system -lboost_system -I${BOOST_ROOT} -o main main.cpp I added to my RPATH using install_name_tool: sudo install_name_tool -add_rpath ${BOOST_ROOT}/stage/lib main >From what I have read from this article here: https://medium.com/@donblas/fun-with-rpath-otool-and-install-name-tool-e3e4… This command appends to the RPATH (@rpath), which is used by LC_LOAD_DYLIB to locate shared library dependencies for the executable. After executing these two commands, my program runs successfully! *Thank you.* However, the learning never ends. That said, I have a bit of an unrelated follow-up question if that is okay. If not, feel free to shun me and I will look elsewhere for an answer. Running these two commands from my terminal is painful and tedious. For troubleshooting, I don't mind, but I want to move toward automation. 1. I tried putting these two commands into a simple script. When I ran the script, main could not be found. *How would I ensure that the main executable from the g++ invocation is outputted into the cwd before the install_name_tool command is executed?* The script I wrote here is just for the sake of experimentation and learning. Ideally, I would use a build tool (i.e. make) for this sort of thing, which I am actually reading about right now. It should be okay to close this issue after my last question is answered/shunned. Thanks again for all of your helpful suggestions, I am starting to like this community already. - AJ On Fri, Jan 31, 2020 at 4:01 AM <boost-users-request(a)lists.boost.org> wrote: > Send Boost-users mailing list submissions to > boost-users(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost-users > or, via email, send a message with subject or body 'help' to > boost-users-request(a)lists.boost.org > > You can reach the person managing the list at > boost-users-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost-users digest..." > > > Today's Topics: > > 1. [Newbie][Interprocess] Placing a boost interprocess vector in > an existing (not managed) shared memory (Gaier, Bjoern) > 2. Re: [Boost.Asio] tutorial #1 code does not compile (g++) > (Andrew McFarlane) > 3. Re: [Boost.Asio] tutorial #1 code does not compile (g++) > (Edward Diener) > 4. Re: [Boost.Asio] tutorial #1 code does not compile (g++) > (Gavin Lambert) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 30 Jan 2020 08:19:02 +0000 > From: "Gaier, Bjoern" <Bjoern.Gaier(a)horiba.com> > To: "boost-users(a)lists.boost.org" <boost-users(a)lists.boost.org> > Subject: [Boost-users] [Newbie][Interprocess] Placing a boost > interprocess vector in an existing (not managed) shared memory > Message-ID: > < > OSAPR01MB3171A3A1ED46336ACEDE2786E2040(a)OSAPR01MB3171.jpnprd01.prod.outlook.com > > > > Content-Type: text/plain; charset="iso-8859-1" > > Hello Boost-Mailing-List, > > I have a question about the boost interprocess library - and I hope I can > explain it correctly. > > I looked at the "Quick guide for the impatient" about the interprocess > library - but I'm not sure if I can use this for our purpose. > The main goal is to insert a STL vector (or different container) in a > predefined portion of an already existing shared memory. The main problem > is, that we cannot use the managed_shared_memory code from boost, because > we rely on a different API to allocate the shared memory between Windows > and other devices. Also the container should be placed at a fixed offset > inside the created shared memory. > > I'm a complete newbie with boost and the interprocess library, that is why > I'm not sure which interface I have to provide for the interprocess vector > to be setup correctly. I hoped I could do something like: > > new (srh_mem_base + offset) boost::interprocess::vector<allocator>; > > I tried looking into the headers of the library to get an idea of that, > but I honestly got lost. > > I'm really sorry if this a stupid or obvious question - and I thank for > any help in advance! > > Kind greetings > Bj?rn > Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, > USt.ID-Nr. DE 114 165 789 Gesch?ftsf?hrer: Dr. Hiroshi Nakamura, Dr. Robert > Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. > Junichi Tajika >

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Re: [Boost-users] [Boost.Asio] tutorial #1 code does not compile (g++)
by Andrew McFarlane 31 Jan '20

31 Jan '20

Okay, so I have made a bit of progress. After building Boost.Asio with: b2 --with-system --with-thread --with-date_time --with-regex --with-serialization stage , and building Boost.Chrono with (replacing bjam with b2): bjam libs/chrono/build The code is now compiling with the following g++ command: g++ -v -Wall -L ${BOOST_ROOT}/stage/lib -L ${BOOST_ROOT}/bin.v2/libs/chrono/build/clang-darwin-11.0/debug/threading-multi/visibility-hidden -lboost_chrono -lboost_date_time -lboost_system -I. -I${BOOST_ROOT} -o main main.cpp However, when I go to run main, the program crashes with the following message: dyld: Library not loaded: @rpath/libboost_chrono.dylib Referenced from: /Users/ajm/Projects/boost-threads/ex1/./main Reason: image not found Abort trap: 6 I suspect that there is something wrong with the Boost.Chrono dynamic library file that was built (probably because of how I built it), but I am not sure what it would be. Any suggestions? Thanks, *Andrew J. E. McFarlane*

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Re: [Boost-users] [Boost.Asio] tutorial #1 code does not compile (g++)
by Andrew McFarlane 29 Jan '20

29 Jan '20

Hi Richard, I suspect you and David are both correct; I need to link boost_chrono. I found here https://www.boost.org/doc/libs/1_72_0/doc/html/chrono/users_guide.html "If BOOST_CHRONO_HEADER_ONLY <https://www.boost.org/doc/libs/1_72_0/doc/html/chrono/reference.html#chrono…> is not defined you need to compile it and build the library before use". This aligns with what you are saying. However, the command it mentions to use, >> bjam libs/chrono/build does not work, even when I am in the boost directory (bjam is not defined). In addition, adding -lboost_chrono or -L{BOOST_ROOT} does not help my case. After reading this article about static and dynamic linked libraries https://medium.com/@dkwok94/the-linking-process-exposed-static-vs-dynamic-l… I suspect I must append the path of boost_chrono to my LD_LIBRARY_PATH variable. Am I correct in this thinking? If so, where the heck is boost_chrono located? I could not find a .a or .so file in libs/chrono/ anywhere. Do I need to build the static/dynamic library myself? Please advise. I apologize for the elementary questions; my compiler and Unix knowledge could be way better, which is something I am working on. Thanks *Andrew J. E. McFarlane* *Cell: (236) 888-1376* On Tue, Jan 28, 2020 at 11:33 PM <boost-users-request(a)lists.boost.org> wrote: > Send Boost-users mailing list submissions to > boost-users(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost-users > or, via email, send a message with subject or body 'help' to > boost-users-request(a)lists.boost.org > > You can reach the person managing the list at > boost-users-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost-users digest..." > > > Today's Topics: > > 1. [Boost.Asio] tutorial #1 code does not compile (g++) > (Andrew McFarlane) > 2. Re: [Boost.Asio] tutorial #1 code does not compile (g++) > (Vinnie Falco) > 3. Re: [Boost.Asio] tutorial #1 code does not compile (g++) > (Andrew McFarlane) > 4. Re: [Boost.Asio] tutorial #1 code does not compile (g++) > (Richard Hodges) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 28 Jan 2020 17:14:58 -0800 > From: Andrew McFarlane <andrew.mcfarlane52(a)gmail.com> > To: boost-users(a)lists.boost.org > Subject: [Boost-users] [Boost.Asio] tutorial #1 code does not compile > (g++) > Message-ID: > <CAG90r9SPGR= > wRUykmftmxTM6oUKbTZYoyat_BR9ufaNpQ0g4Rw(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi All, > > I am attempting to get acquainted with C++ multithreaded network > programming. I have a background in such topics within Java but considering > how different C++ is, I am starting from ground zero. > > I have copied the code from tutorial #1 into my IDE, Timer.1: Using a timer > synchronously: > > https://www.boost.org/doc/libs/1_72_0/doc/html/boost_asio/tutorial/tuttimer… > (follow > the link for code). > > When I tried to compile this (using g++) with the following command: > > g++ -v -I${BOOST_ROOT} -I. -o main main.cpp > (BOOST_ROOT is where I have boost installed), I get the following output: > > Undefined symbols for architecture x86_64: > > "boost::chrono::steady_clock::now()", referenced from: > > boost::asio::detail::chrono_time_traits<boost::chrono::steady_clock, > boost::asio::wait_traits<boost::chrono::steady_clock> >::now() in > main-c86634.o > > ld: symbol(s) not found for architecture x86_64 > > clang: error: linker command failed with exit code 1 (use -v to see > invocation) > Note this is the non-verbose output (I would rather not post the verbose > output, as I am trying to keep this post short). > > I did some digging of my own on Boost's steady_timer documentation and > tried to follow that style, as you can find here: > > https://www.boost.org/doc/libs/1_72_0/doc/html/boost_asio/reference/steady_… > In other words, I replace the two-parameter boost::asio::steady_timer ctor > call with a single-parameter ctor call in which I pass an io_context, > followed by > t.expires_after(std::chrono::seconds(5)); > > This generated another compiler error, this one to do with 'no viable > conversion'. See here: > > main.cpp:10:21: error: no viable conversion from 'std::chrono::seconds' > (aka > > 'duration<long long>') to 'const > > boost::asio::basic_waitable_timer<boost::chrono::steady_clock, > > boost::asio::wait_traits<boost::chrono::steady_clock>, > > boost::asio::executor>::duration' (aka 'const duration<long long, > > ratio<(1L), (1000000000L)> >') > > t.expires_after(std::chrono::seconds(5)); > Again, there is more output that I have omitted for brevity. If anyone > would like to see the rest of the output, I will gladly supply it. > > The bottom line is I am not sure what the problem is, or why I am having to > debug tutorial code in the first place. This should be relatively simple to > "plug & play", should it not? Does this have to do with my compiler? BTW, I > am running Mac OS X. > > Thanks in advance for the help. > > Sincerely, > > *AJ* >

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[Boost.Asio] tutorial #1 code does not compile (g++)
by Andrew McFarlane 29 Jan '20

29 Jan '20

Hi All, I am attempting to get acquainted with C++ multithreaded network programming. I have a background in such topics within Java but considering how different C++ is, I am starting from ground zero. I have copied the code from tutorial #1 into my IDE, Timer.1: Using a timer synchronously: https://www.boost.org/doc/libs/1_72_0/doc/html/boost_asio/tutorial/tuttimer… (follow the link for code). When I tried to compile this (using g++) with the following command: g++ -v -I${BOOST_ROOT} -I. -o main main.cpp (BOOST_ROOT is where I have boost installed), I get the following output: Undefined symbols for architecture x86_64: "boost::chrono::steady_clock::now()", referenced from: boost::asio::detail::chrono_time_traits<boost::chrono::steady_clock, boost::asio::wait_traits<boost::chrono::steady_clock> >::now() in main-c86634.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) Note this is the non-verbose output (I would rather not post the verbose output, as I am trying to keep this post short). I did some digging of my own on Boost's steady_timer documentation and tried to follow that style, as you can find here: https://www.boost.org/doc/libs/1_72_0/doc/html/boost_asio/reference/steady_… In other words, I replace the two-parameter boost::asio::steady_timer ctor call with a single-parameter ctor call in which I pass an io_context, followed by t.expires_after(std::chrono::seconds(5)); This generated another compiler error, this one to do with 'no viable conversion'. See here: main.cpp:10:21: error: no viable conversion from 'std::chrono::seconds' (aka 'duration<long long>') to 'const boost::asio::basic_waitable_timer<boost::chrono::steady_clock, boost::asio::wait_traits<boost::chrono::steady_clock>, boost::asio::executor>::duration' (aka 'const duration<long long, ratio<(1L), (1000000000L)> >') t.expires_after(std::chrono::seconds(5)); Again, there is more output that I have omitted for brevity. If anyone would like to see the rest of the output, I will gladly supply it. The bottom line is I am not sure what the problem is, or why I am having to debug tutorial code in the first place. This should be relatively simple to "plug & play", should it not? Does this have to do with my compiler? BTW, I am running Mac OS X. Thanks in advance for the help. Sincerely, *AJ*

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[Regex]: Can a possible non-matched group be prevented from being reported?
by Eko palypse 24 Jan '20

24 Jan '20

Hopefully I'm not posting this again. Hello, I'm wrapping boost::regex with cython to be able to call it from python. Assuming a "Hello World" text and a regex (\w+)*. This results in two matches. groups ('Hello', 'Hello') lastindex 1 group:0 Hello start 0 end 5 group:1 Hello start 0 end 5 groups ('', '') lastindex 1 group:0 start 5 end 5 group:1 start -1 end -1 I understand, that there is always the main match in group0 and matches from capturing groups in group1 ... As we see, the second match, the zero-length-width match, reports two groups but the second group returns -1. Is it possible to prevent such matches to be reported beforehand? Or is it needed to iterate over the groups to eliminate those? Just in case it is needed to see my code logic, this is what I'm doing currently def unicode_research_iter(const wchar_t* text, wchar_t* pattern, int flags): cdef: wcmatch what size_t _length size_t _position wcregex_iterator start, end try: start = make_regex_iterator(text, <wregex>pattern, match_flags.match_perl) end = wcregex_iterator() while (start != end): what = <wcmatch>deref(start) if not what.empty(): match_object = UnicodeMatch.from_instance(what) yield match_object else: print('Empty match result: ??') inc(start) # increment except Exception as e: raise RuntimeError(f'{e}') Thank you Eren

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