Necessary singletons are not exposed when compiling shared library with hidden visibility

[ZijunH]

Consider the following toy example:

CMakeLists.txt:

cmake_minimum_required(VERSION 3.21)

project(foo)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED true)
set(CMAKE_CXX_VISIBILITY_PRESET hidden)

set(CMAKE_BUILD_TYPE RelWithDebInfo)

add_subdirectory(quill)

add_library(logger_lib SHARED logger_lib.cpp)
target_link_libraries(logger_lib PUBLIC
  quill::quill
)

add_executable(logger logger.cpp)
target_link_libraries(logger PUBLIC
  logger_lib
)

logger_lib.cpp

#include "quill/Backend.h"
#include "quill/Frontend.h"
#include "quill/LogMacros.h"
#include "quill/Logger.h"
#include "quill/sinks/ConsoleSink.h"

[[gnu::visibility("default")]] quill::Logger* start_logger() {
    quill::Backend::start();

    auto console_sink = quill::Frontend::create_or_get_sink<quill::ConsoleSink>("sink_id_1");
    return quill::Frontend::create_or_get_logger("root", std::move(console_sink));
}

logger.cpp

#include "quill/Backend.h"
#include "quill/Frontend.h"
#include "quill/LogMacros.h"
#include "quill/Logger.h"
#include "quill/sinks/ConsoleSink.h"

quill::Logger* start_logger();

int main(){
  LOG_INFO(start_logger(), "This is a log info example {}", 123);
}

When compiled, the the logger does not print anything to the terminal. This is because the singletons (the static instance()) functions are not properly exposed in the shared library.

This is a similar issue to #222. Manually exporting the various static instance() functions by [[gnu::visibility("default")]] solves the issue on linux.

[odygrd]

Hey, thanks for reporting. I think I removed those since the library is header only i wasn't expecting it to build as shared library anymore. I will get it fixed over the next few days

[odygrd]

this is fixed with af9eb90