Examples

Simple

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

#include "quill/std/Array.h"

#include <string>
#include <utility>

int main()
{
  quill::BackendOptions backend_options;
  quill::Backend::start(backend_options);

  // Frontend
  auto console_sink = quill::Frontend::create_or_get_sink<quill::ConsoleSink>("sink_id_1");
  quill::Logger* logger = quill::Frontend::create_or_get_logger("root", std::move(console_sink));

  // Change the LogLevel to print everything
  logger->set_log_level(quill::LogLevel::TraceL3);

  // A log message with number 123
  int a = 123;
  std::string l = "log";
  LOG_INFO(logger, "A {} message with number {}", l, a);

  // libfmt formatting language is supported 3.14e+00
  double pi = 3.141592653589793;
  LOG_INFO(logger, "libfmt formatting language is supported {:.2e}", pi);

  // Logging STD types is supported [1, 2, 3]
  std::array<int, 3> arr = {1, 2, 3};
  LOG_INFO(logger, "Logging STD types is supported {}", arr);

  // Logging STD types is supported [arr: [1, 2, 3]]
  LOGV_INFO(logger, "Logging STD types is supported", arr);

  // A message with two variables [a: 123, b: 3.17]
  double b = 3.17;
  LOGV_INFO(logger, "A message with two variables", a, b);

  for (uint32_t i = 0; i < 10; ++i)
  {
    // Will only log the message once per second
    LOG_INFO_LIMIT(std::chrono::seconds{1}, logger, "A {} message with number {}", l, a);
    LOGV_INFO_LIMIT(std::chrono::seconds{1}, logger, "A message with two variables", a, b);
  }
}

Logging to file

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

#include <utility>

int main()
{
  // Start the backend thread
  quill::BackendOptions backend_options;
  quill::Backend::start(backend_options);

  // Frontend
  auto file_sink = quill::Frontend::create_or_get_sink<quill::FileSink>(
    "trivial_logging.log",
    []()
    {
      quill::FileSinkConfig cfg;
      cfg.set_open_mode('w');
      cfg.set_filename_append_option(quill::FilenameAppendOption::StartDateTime);
      return cfg;
    }(),
    quill::FileEventNotifier{});

  quill::Logger* logger =
    quill::Frontend::create_or_get_logger("root", std::move(file_sink),
                                          quill::PatternFormatterOptions { "%(time) [%(thread_id)] %(short_source_location:<28) "
                                          "LOG_%(log_level:<9) %(logger:<12) %(message)",
                                          "%H:%M:%S.%Qns", quill::Timezone::GmtTime });

  // set the log level of the logger to debug (default is info)
  logger->set_log_level(quill::LogLevel::Debug);

  LOG_INFO(logger, "log something {}", 123);
  LOG_DEBUG(logger, "something else {}", 456);
}