I tried to build this example and got a linkage error:
hekto@ubuntu:~$ g++ -g -Wall -std=c++11 -pthread -DBOOST_LOG_DYN_LINK -pthread sample.cpp -o sample -lboost_log -lboost_thread -lboost_system
/tmp/cc2EUizv.o: In function `boost::log::v2_mt_posix::basic_formatter<char> boost::log::v2_mt_posix::parse_formatter<char>(char const*)':
/usr/include/boost/log/utility/setup/formatter_parser.hpp:207: undefined reference to `boost::log::v2_mt_posix::basic_formatter<char> boost::log::v2_mt_posix::parse_formatter<char>(char const*, char const*)'
collect2: error: ld returned 1 exit status
How to overcome that?
I'm answering my own question, following the @Praetorian help and suggestion.
The Boost Log relies on two libraries (I thought it was only one):
hekto@ubuntu:~$ ls -l /usr/lib/x86_64-linux-gnu/libboost_log*
-rw-r--r-- 1 root root 3510082 Mar 6 2018 /usr/lib/x86_64-linux-gnu/libboost_log.a
-rw-r--r-- 1 root root 2441460 Mar 6 2018 /usr/lib/x86_64-linux-gnu/libboost_log_setup.a
lrwxrwxrwx 1 root root 28 Mar 6 2018 /usr/lib/x86_64-linux-gnu/libboost_log_setup.so -> libboost_log_setup.so.1.65.1
-rw-r--r-- 1 root root 671944 Mar 6 2018 /usr/lib/x86_64-linux-gnu/libboost_log_setup.so.1.65.1
lrwxrwxrwx 1 root root 22 Mar 6 2018 /usr/lib/x86_64-linux-gnu/libboost_log.so -> libboost_log.so.1.65.1
-rw-r--r-- 1 root root 905752 Mar 6 2018 /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1
If you compile and link on Linux, you'll have to provide a list of Boost libraries on the command line. According to an answer to this question, given by the main developer (@AndreySemashev) of the Boost Log, these libraries on the command line should look like this:
-lboost_log_setup -lboost_log
Probably it makes sense to provide two libraries instead of one (for example, when you link statically), but I couldn't find any recommendations about when we should use a single library, and when - both of them.