How to set the severity level of Boost log library

Question

I have been successfully using the Boost Log library in my project. In other words, I am emitting log messages via BOOST_LOG_TRIVIAL(info) << "My message";

Now I want to control the severity of logging, and I followed the example from the Boost Log library documentation:

#include <boost/log/trivial.hpp>
#include <boost/log/core.hpp>

namespace logging = boost::log;

void init()
{
    logging::core::get()->set_filter
    (
        logging::trivial::severity >= logging::trivial::info
    );
}

However, I am getting this compilation error:

main.cpp:22:25: error: ‘severity’ is not a member of ‘boost::log::v2s_mt_posix::trivial’
   22 |       logging::trivial::severity >= logging::trivial::info

Here is the relevant section of my CMakeLists.txt:

SET(Boost_USE_STATIC_LIBS ON)
find_package(Boost 1.71 COMPONENTS log graph REQUIRED)
include_directories(${Boost_INCLUDE_DIRS})

add_executable(ls_router main.cpp)
target_link_libraries(ls_router PUBLIC ${Boost_LIBRARIES} pthread)

I am on Ubuntu and installed Boost via sudo apt install libboost-all-dev.

dpkg -l | grep libboost-log
ii  libboost-log-dev                       1.71.0.0ubuntu2                       amd64        C++ logging library (default version)
ii  libboost-log1.71-dev                   1.71.0-6ubuntu6                       amd64        C++ logging library
ii  libboost-log1.71.0                     1.71.0-6ubuntu6                       amd64        C++ logging library

According to this SO question, this might be a CMake configuration issue. Boost.Log with CMake causing undefined reference error. However, none of the suggestions in the question solved my issue.

score 1 · Accepted Answer · answered Nov 14 '21 at 23:12

The severity keyword is defined in boost/log/detail/trivial_keyword.hpp. Apparently it's not being included.

The minimal set of includes I could find:

#include <boost/log/core.hpp>
#include <boost/log/trivial.hpp>
#include <boost/log/expressions.hpp>

namespace logging = boost::log;

void init()
{
    logging::core::get()->set_filter(logging::trivial::severity >=
                                     logging::trivial::info);
}

int main() { init(); }

According to this SO question, this might be a CMake configuration issue

That's about linker errors, which this isn't.

How to set the severity level of Boost log library

1 Answers1