How to use Boost C++ Libraries on MacOS

Question

I am trying to use Boost Libraries on MacOS.

I installed boost using brew install boost. This installed boost in usr/local/Cellar/boost.

I compiled 2 programs with the same command g++ --std=c++11 main.cpp -o main and then ./main

However the first one compiled successfully while the second one doesn't. What should I do?

Program1.

#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) << " " );
}

Program2.

#include <boost/test/unit_test.hpp>

int add( int i, int j ) { return i+j; }

BOOST_AUTO_TEST_CASE( my_test )
{
    BOOST_CHECK( add( 2,2 ) == 4 );       

    BOOST_REQUIRE( add( 2,2 ) == 4 );     

    if( add( 2,2 ) != 4 )
      BOOST_ERROR( "Ouch..." );      

    if( add( 2,2 ) != 4 )
      BOOST_FAIL( "Ouch..." );           

    if( add( 2,2 ) != 4 ) throw "Ouch..."; 

    BOOST_CHECK_MESSAGE( add( 2,2 ) == 4, 
                         "add(..) result: " << add( 2,2 ) );

    BOOST_CHECK_EQUAL( add( 2,2 ), 4 );  
}

I get the following error when I compile program 2.

Undefined symbols for architecture x86_64:
  "boost::test_tools::tt_detail::report_assertion(boost::test_tools::assertion_result const&, boost::unit_test::lazy_ostream const&, boost::unit_test::basic_cstr
ing<char const>, unsigned long, boost::test_tools::tt_detail::tool_level, boost::test_tools::tt_detail::check_type, unsigned long, ...)", referenced from:
      my_test::test_method() in del-9b4dcb.o

      bool boost::test_tools::tt_detail::check_frwd<boost::test_tools::tt_detail::equal_impl_frwd, int, int>(boost::test_tools::tt_detail::equal_impl_frwd, boost
::unit_test::lazy_ostream const&, boost::unit_test::basic_cstring<char const>, unsigned long, boost::test_tools::tt_detail::tool_level, boost::test_tools::tt_det
ail::check_type, int const&, char const*, int const&, char const*) in del-9b4dcb.o
  "boost::unit_test::unit_test_log_t::set_checkpoint(boost::unit_test::basic_cstring<char const>, unsigned long, boost::unit_test::basic_cstring<char const>)", r
eferenced from:
      my_test_invoker() in del-9b4dcb.o
      my_test::test_method() in del-9b4dcb.o
  "boost::unit_test::test_case::test_case(boost::unit_test::basic_cstring<char const>, boost::unit_test::basic_cstring<char const>, unsigned long, boost::functio
n<void ()> const&)", referenced from:
      boost::unit_test::make_test_case(boost::function<void ()> const&, boost::unit_test::basic_cstring<char const>, boost::unit_test::basic_cstring<char const>,
 unsigned long) in del-9b4dcb.o
  "boost::unit_test::ut_detail::auto_test_unit_registrar::auto_test_unit_registrar(boost::unit_test::test_case*, boost::unit_test::decorator::collector&, unsigne
d long)", referenced from:
      ___cxx_global_var_init.1 in del-9b4dcb.o
  "boost::unit_test::ut_detail::normalize_test_case_name(boost::unit_test::basic_cstring<char const>)", referenced from:
      boost::unit_test::make_test_case(boost::function<void ()> const&, boost::unit_test::basic_cstring<char const>, boost::unit_test::basic_cstring<char const>,
 unsigned long) in del-9b4dcb.o
  "vtable for boost::unit_test::unit_test_log_t", referenced from:
      boost::unit_test::unit_test_log_t::unit_test_log_t() in del-9b4dcb.o
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "_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)

Answer 1

Looking at boost's documentation you may want to try the following include statement.

#include <boost/test/included/unit_test.hpp>

Answer 2

Linker errors happen when the compiler fails to find required library binaries. You need to specify the path to the boost test library. The thing is where your boost libraries are - probably not /usr/local/lib, but /usr/local/Cellar/boost/.../lib on Mac.

So use something like

g++ -L/usr/local/Cellar/boost/.../lib main.cpp -o main -lboost_unit_test_framework