April 2020 - Boost-users - lists.preview.boost.org

[Boost.Test] linking with shared lib (cannot find main)
by Andrew McFarlane 06 Apr '20

06 Apr '20

Hi all, I have been using Boost.Test for about a month now. Big fan so far, except for the atrocious compilation times, hence why I am moving toward using the shared library. using b2 to build and install Boost.Test's libs was simple enough, though after making the noted changes here: https://www.boost.org/doc/libs/1_72_0/libs/test/doc/html/boost_test/adv_sce… to customize the module's entry point, g++ cannot find the main executable: Undefined symbols for architecture x86_64: "_main", referenced from: implicit entry/start for main executable ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [Guest_T] Error 1 I tried digging through the docs for more information, but I came up short. For more context, I have written unit tests for each of my classes. For example, if my classes were A, B, and C, I would have A_T.cpp, B_T.cpp, and C_T.cpp for unit tests. - Should each of the unit tests have their own main() function? (I would think not..) - If not, how do I instruct g++ to first compile main.cpp before attempting to compile anything else? If you are curious, here are the contents of my Makefile: PROG := main CC := g++ SDIR := ../src PKG_DIRS := $(shell ls $(SDIR)) CXXFLAGS = -v -Wall -std=c++11 -I$(SDIR_TEST) \ $(addprefix -I$(SDIR)/,$(PKG_DIRS)) -I$(BOOST_ROOT) \ -L$(BOOST_LIBS) -Wl,-rpath,$(BOOST_LIBS) -lboost_unit_test_framework ODIR_TEST = ./bin SDIR_TEST = ./src OUTDIR = ./execs ODIR = ../sim/bin TEST_EXEC_NAMES = $(notdir $(basename $(wildcard $(SDIR_TEST)/*.cpp))) $(OUTDIR)/$(PROG) : $(SDIR_TEST)/main.cpp $(CC) $(CXXFLAGS) -o $@ $< $(OUTDIR)/$(PROG) : $(TEST_EXEC_NAMES) $(CC) $(CXXFLAGS) -o $@ $^ % : $(SDIR_TEST)/%.cpp $(CC) $(CXXFLAGS) -o $(OUTDIR)/$@ $^ >From what I can tell, g++ is failing to find the main the executable because it is attempting to compile one of my unit test files first. This may or may not be the case; either way, I would appreciate some help or direction as to what I should read to learn more about this. Let me know if you need more info. Thanks in advance. - AJ

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[Boost.Test] duplicate symbol '_main' (manual test registration)
by Andrew McFarlane 06 Apr '20

06 Apr '20

Hi all, As the subject line suggests, I am attempting to manually employ a master test suite that registers several sub test suites. - Each subtest suite has its own header and translation unit. - Each header has a public "init_test_suite()" method and several private "test_case<number>()" methods, all of which are declared static. The public method creates a test suite, adds all the test cases for that translation unit, and adds the suite to the master test suite. This method is intended to be called from main.cpp. Here is a simplified version of my main.cpp: #define BOOST_TEST_DYN_LINK #define BOOST_TEST_NO_MAIN #include <boost/test/unit_test.hpp> #include "A.h" #include "B_T.h" #include "C_T.h" bool register_test_suites() { A_T::init_test_suite(); B_T::init_test_suite(); C_T::init_test_suite(); return 0; } int main(int argc, char *argv[], char *envp[]) { return boost::unit_test::unit_test_main(&register_test_suites, argc, argv); } Here's the issue. Despite the fact that I have defined BOOST_TEST_NO_MAIN, it appears that my compiler is still generating 2 objects files for the main executable entry: duplicate symbol 'register_test_suites()' in: /var/folders/bc/v2yqpsf96kn31tx8ybvy9gyw0000gn/T/main-58c6b3.o bin/main.o duplicate symbol '_main' in: /var/folders/bc/v2yqpsf96kn31tx8ybvy9gyw0000gn/T/main-58c6b3.o bin/main.o ld: 2 duplicate symbols for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [execs/main] Error 1 As you might be wondering, all of my test translation units define BOOST_TEST_DYN_LINK, and none of them define BOOST_TEST_MODULE, as the documentation suggests. I tried removing BOOST_TEST_NO_MAIN from main.cpp but that did not appear to do anything. I also tried removing the static and shared Boost.Unit lib files from my stage/lib directory and rebuilding only the shared version, and that did not work either. Also not that my g++ command does have the expected -L and -l flags for linking with Boost.Test: -L/usr/local/boost_1_72_0/stage/lib -lboost_unit_test_framework I am lost here. No idea why main() is being defined twice. Thanks in advance. - AJ

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BOOST_TEST_STRING_VIEW
by Leo Carreon 06 Apr '20

06 Apr '20

Hi Boost Users, Does anyone know what BOOST_TEST_STRING_VIEW is for? Kind regards, Leo

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Issue upgrading boost from 1.5.6 to 1.7.2
by Luke Knoble 06 Apr '20

06 Apr '20

Ello!! This is my first time using a mail group! I'm using Visual Studio 2019. My error is this: error C2977: 'boost::mpl::map': too many template arguments I'm using about 139 arguments for this map. Do I need to rebuild Boost with some custom flag? Thanks, Luke

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boost range dynamic joined_range
by Lars Sunde 06 Apr '20

06 Apr '20

Hello, How can I create a Boost Range for multiple vectors without setting any limitation to the number of vector at compile time? Using Boost 1.70 and it is not an option to store all data in one vector. The following code compile on Visual Studio 2017 and will output the number 1 to 9. However, this code is compiled to support 3 vectors inside the foo struct. In order to support 4 vectors I would need to re-compile the code. The number of vectors is only known at runtime. How can this code be improved to support a dynamic number of vectors ? #include <iostream> #include <vector> #include <boost/range.hpp> #include <boost/range/join.hpp> struct foo { typedef boost::range::joined_range< boost::range::joined_range< std::vector<int>, std::vector<int>>, std::vector<int>> range; std::vector<std::vector<int>> vec; foo() { vec = { {1,2,3}, {4,5,6}, {7,8,9} }; } range my_range() { auto range1 = boost::join(vec[0], vec[1]); return boost::join(range1, vec[2]); } }; int main() { foo f1; for (auto item : f1.my_range()) std::cout << item << " "; return 0; } Appreciate any input. Kind regards, Lars

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[type-erasure?] callable configurable type-erasure
by Igor R 05 Apr '20

05 Apr '20

Hi, In my project I need a callable type-erasure - just like std::function/boost::function, but with a *configurable* small-object optimization (I will use it in a context where dynamic allocation is highly discouraged, so I'm going to make relatively big "static" holder). Is it possible to use TypeErasure library this way? Or maybe we have some other facilities in Boost that could be useful for this purpose? Thanks.

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asio and custom socket implementation
by Stanislav Zaikin 03 Apr '20

03 Apr '20

Hello! I have a custom network stack (it processed packets in userspace) which exposed some functions in C. It has its own listen, bind, accept functions and many other, and furthermore even custom epoll, select and poll. I want to expand asio in some away, just to support my application with this custom network stack. But I'm a bit confused how I can do it. Should I write my own basic io class? Or should I write custom socket service class like (reactive_socket_service_base)? And is it possible to use basic tcp classes (with any of them)? If there are any examples in open source please let me know. -- Best regards Stanislav Zaikin

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