//Create and return a shared_ptr to a multithreaded console logger.
#include "spdlog/sinks/stdout_color_sinks.h"
auto console = spdlog::stdout_color_mt("some_unique_name");

spd::register_logger(my_logger)

//Create rotating file multi-threaded logger
#include "spdlog/sinks/rotating_file_sink.h"
auto file_logger = spdlog::rotating_logger_mt("file_logger", "logs/mylogfile", 1048576 * 5, 3);
...
auto same_logger= spdlog::get("file_logger");

#include "spdlog/async.h"
void async_example()
{
    // default thread pool settings can be modified *before* creating the async logger:
    // spdlog::init_thread_pool(8192, 1); // queue with 8k items and 1 backing thread.
    auto async_file = spdlog::basic_logger_mt<spdlog::async_factory>("async_file_logger", "logs/async_log.txt");
    // alternatively:
    // auto async_file = spdlog::create_async<spdlog::sinks::basic_file_sink_mt>("async_file_logger", "logs/async_log.txt");

}

auto sink = std::make_shared<spdlog::sink::stdout_sink_mt>();
auto my_logger = std::make_shared<spdlog::logger>("mylogger", sink);

std::vector<spdlog::sink_ptr> sinks;
sinks.push_back(std::make_shared<spdlog::sinks::stdout_sink_st>());
sinks.push_back(std::make_shared<spdlog::sinks::daily_file_sink_st>("log_file", 23, 59));
auto logger = std::make_shared<spdlog::logger>("mylogger", begin(sinks), end(sinks));
spdlog::register_logger(logger);

auto sharedFileSink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("fileName.txt");
auto firstLogger = std::make_shared<spdlog::logger>("first", sharedFileSink);
auto secondLogger = std::make_unique<spdlog::logger>("second", sharedFileSink);

some_logger->sinks()[0]->set_pattern(">>>>>>>>> %H:%M:%S %z %v <<<<<<<<<");
some_logger->sinks()[1]->set_pattern("..");

#include "spdlog/sinks/base_sink.h"

template<typename Mutex>
class my_sink : public spdlog::sinks::base_sink <Mutex>
{
...
protected:
    void sink_it_(const spdlog::details::log_msg& msg) override
    {

    // log_msg is a struct containing the log entry info like level, timestamp, thread id etc.
    // msg.raw contains pre formatted log

    // If needed (very likely but not mandatory), the sink formats the message before sending it to its final destination:
    spdlog::memory_buf_t formatted;
    spdlog::sinks::base_sink<Mutex>::formatter_->format(msg, formatted);
    std::cout << fmt::to_string(formatted);
    }

    void flush_() override 
    {
       std::cout << std::flush;
    }
};

#include "spdlog/details/null_mutex.h"
#include <mutex>
using my_sink_mt = my_sink<std::mutex>;
using my_sink_st = my_sink<spdlog::details::null_mutex>;

inline std::vector<spdlog::sink_ptr> &spdlog::logger::sinks()
{
    return sinks_;
}


spdlog::get("myExistingLogger")->sinks().push_back(myNewSink);

spdlog::get("logger1")->info("hello");
.. 
.. 
some other source file..
..
auto l = spdlog::get("logger1");
l->info("hello again");

spdlog::drop("logger_name");
//or remove them all
spdlog::drop_all()

#include "spdlog/async.h"
void async_example()
{
    // default thread pool settings can be modified *before* creating the async logger:
    // spdlog::init_thread_pool(8192, 1); // queue with 8k items and 1 backing thread.
    auto async_file = spdlog::basic_logger_mt<spdlog::async_factory>("async_file_logger", "logs/async_log.txt");
}

auto async_file = spdlog::create_async<spdlog::sinks::basic_file_sink_mt>("async_file_logger", "logs/async_log.txt");    

auto async_file = spdlog::create_async_nb<spdlog::sinks::basic_file_sink_mt>("async_file_logger", "logs/async_log.txt");

spdlog::init_thread_pool(queue_size, n_threads);
auto logger = std::make_shared<spdlog::async_logger>("as", some_sink, spdlog::thread_pool(), async_overflow_policy::block);

auto tp = std::make_shared<details::thread_pool>(queue_size, n_threads);
auto logger = std::make_shared<spdlog::async_logger>("as", some_sink, tp, async_overflow_policy::block);

auto logger = spdlog::create_async_nb<spdlog::sinks::basic_file_sink_mt>("async_file_logger", "logs/async_log.txt");
// or directly:
 auto logger = std::make_shared<async_logger>("as", test_sink, spdlog::thread_pool(), spdlog::async_overflow_policy::overrun_oldest);

spdlog::init_thread_pool(queue_size, n_threads);

auto tp = std::make_shared<details::thread_pool>(128, 1);
auto logger = std::make_shared<async_logger>("as", some_sink, tp, async_overflow_policy::overrun_oldest);

auto tp2 = std::make_shared<details::thread_pool>(1024, 4);  // create pool with queue of 1024 slots and 4 backing threads
auto logger2 = std::make_shared<async_logger>("as2", some_sink, tp2, async_overflow_policy::block);

my_logger->flush_on(spdlog::level::err); 

spdlog::flush_every(std::chrono::seconds(5));

spdlog::set_default_logger(some_other_logger);
spdlog::info("Use the new default logger");

my_logger->flush();                            // flush now
my_logger->flush_on(spdlog::level::info);      // auto flush when "info" or higher message is logged
spdlog::flush_on(spdlog::level::info);         // auto flush when "info" or higher message is logged on all loggers
spdlog::flush_every(std::chrono::seconds(5));  // flush periodically every 5 seconds (caution: must be _mt logger)

#define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_INFO // All DEBUG/TRACE statements will be removed by the pre-processor
#include "spdlog/spdlog.h"
...
SPDLOG_DEBUG("debug message to default logger"); // removed at compile time
SPDLOG_LOGGER_TRACE(my_logger, "trace message"); // removed at compile time
SPDLOG_INFO("info message to default logger");   // included

spdlog::shutdown();