vcpkg install spdlog

sudo apt install libspdlog-dev

include(FetchContent)
FetchContent_Declare(spdlog
    GIT_REPOSITORY https://github.com/gabime/spdlog.git
    GIT_TAG v1.13.0
)
FetchContent_MakeAvailable(spdlog)
target_link_libraries(MyApp spdlog::spdlog)

#include <spdlog/spdlog.h>

#include <spdlog/spdlog.h>
 
int main() {
    spdlog::info("Hello, {}!", "world");
    spdlog::warn("Warning: value is {}", 42);
    spdlog::error("Error code: {}", -1);
    spdlog::critical("Critical failure!");
    spdlog::debug("Debug: x={}, y={}", 1.5, 2.5);
    spdlog::trace("Trace level message");
}
// Output: [2024-01-01 12:00:00.000] [info] Hello, world!

// Levels (lowest to highest):
// trace < debug < info < warn < error < critical < off
 
spdlog::set_level(spdlog::level::debug); // show debug and above
spdlog::set_level(spdlog::level::warn);  // show warn and above only
 
spdlog::debug("This shows if level <= debug");
spdlog::info("This shows if level <= info");

#include <spdlog/spdlog.h>
 
auto logger = spdlog::stdout_color_mt("my_logger");
logger->info("Message from named logger");
logger->set_level(spdlog::level::debug);
 
// Retrieve logger by name anywhere in code
auto same = spdlog::get("my_logger");
same->warn("Retrieved logger");

#include <spdlog/sinks/stdout_color_sinks.h>
 
auto console = spdlog::stdout_color_mt("console");
console->info("Colored console output");
 
// stderr
auto err_logger = spdlog::stderr_color_mt("stderr");
err_logger->error("Error to stderr");

#include <spdlog/sinks/basic_file_sink.h>
 
auto file_logger = spdlog::basic_logger_mt("file_logger", "logs/app.log");
file_logger->info("Logged to file");
 
// Truncate on open
auto trunc = spdlog::basic_logger_mt("trunc", "logs/app.log", true);

#include <spdlog/sinks/rotating_file_sink.h>
 
// Max 5MB per file, keep 3 files
auto rotating = spdlog::rotating_logger_mt(
    "rotating", "logs/app.log",
    1024 * 1024 * 5,  // 5MB
    3                  // 3 files
);
rotating->info("This rotates when file hits 5MB");

#include <spdlog/sinks/daily_file_sink.h>
 
// New file every day at 02:30
auto daily = spdlog::daily_logger_mt("daily", "logs/daily.log", 2, 30);
daily->info("Daily log entry");

#include <spdlog/sinks/stdout_color_sinks.h>
#include <spdlog/sinks/rotating_file_sink.h>
#include <spdlog/logger.h>
 
auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
auto file_sink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(
    "logs/multi.log", 1024*1024, 5);
 
spdlog::logger logger("multi", {console_sink, file_sink});
logger.info("Goes to both console and file");

#include <spdlog/async.h>
#include <spdlog/sinks/basic_file_sink.h>
 
// Initialize async thread pool: queue size, thread count
spdlog::init_thread_pool(8192, 1);
 
auto async_logger = spdlog::basic_logger_async_mt(
    "async_logger", "logs/async.log");
 
async_logger->info("Non-blocking async log");
 
// Flush before exit
spdlog::shutdown();

// Pattern flags:
// %Y-%m-%d  date
// %H:%M:%S  time
// %e        milliseconds
// %l        log level
// %n        logger name
// %v        message
// %t        thread id
// %s        source file
// %#        source line
 
spdlog::set_pattern("[%Y-%m-%d %H:%M:%S.%e] [%n] [%l] [thread %t] %v");
spdlog::info("Custom pattern message");
// [2024-01-01 12:00:00.123] [root] [info] [thread 1234] Custom pattern message

// Flush on every error or above
spdlog::flush_on(spdlog::level::err);
 
// Periodic flush every 3 seconds
spdlog::flush_every(std::chrono::seconds(3));
 
// Manual flush
spdlog::get("my_logger")->flush();