Log() method and LOG macro

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KasperskyOS API > LogRR component > LogRR program API > logrr_cpp library > Log() method and LOG macro

Log() method and LOG macro

The logrr::Log() method writes to the log.

Method parameters:

logLevel: Log level LogLevel.
sourceLocation: Object that determines the location in the source code (file name, function name, line number and column number). The std::source_location class is used in C++20, while the std::experimental::source_location class is used in earlier versions.
format: Message text formatting string.
args: Parameters to be inserted into the format formatting string.

The logrr::Log() method is intended for use in C++ programs. In C-language programs, use the static function ClogLog() or CLOG macro.

A description of the logrr::Log() method and macros for quick access to it are provided in the file /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/component/logrr/cpp/logger.h.

component/logrr/cpp/logger.h (fragment)

namespace logrr {

namespace details {

__rtl_public
void PrintErrorMessage(std::string_view fileName, std::uint32_t line, std::string_view exMsg) noexcept;

} // namespace details

__rtl_public
void Init(std::string_view providerName) noexcept;

__rtl_public
bool ShouldLog(logrr::LogLevel logLevel) noexcept;

__rtl_public
void SendMessage(
    std::string_view module,
    LogLevel logLevel,
    std::string_view file,
    const uint32_t line,
    std::string_view function,
    std::string_view msg) noexcept;

template <typename... Args>
__rtl_public
void Log(
    logrr::LogLevel logLevel,
    kos::rtl::SourceLocation sourceLocation,
    std::string_view format,
    Args&&... args) noexcept
{
    Log(logLevel, sourceLocation.file_name(), sourceLocation.line(),
        sourceLocation.function_name(), format, std::forward<Args>(args)...);
}

template <typename... Args>
__rtl_public
void Log(
    std::string_view module,
    logrr::LogLevel logLevel,
    kos::rtl::SourceLocation sourceLocation,
    std::string_view format,
    Args&&... args) noexcept
{
    Log(module, logLevel, sourceLocation.file_name(), sourceLocation.line(),
        sourceLocation.function_name(), format, std::forward<Args>(args)...);
}

template <typename... Args>
__rtl_public
void Log(
    logrr::LogLevel logLevel,
    std::string_view file,
    const uint32_t line,
    std::string_view function,
    std::string_view format,
    Args&&... args) noexcept
{
    Log("", logLevel, file, line, function, format, std::forward<Args>(args)...);
}

template <typename... Args>
__rtl_public
void Log(
    std::string_view module,
    logrr::LogLevel logLevel,
    std::string_view file,
    const uint32_t line,
    std::string_view function,
    std::string_view format,
    Args&&... args) noexcept
{
    if (ShouldLog(logLevel))
    try
    {
        constexpr auto MaxLength = static_cast<std::size_t>(LOGRR_LOG_MESSAGE_MAX_SIZE - 1);
        if constexpr (!sizeof...(args))
        {
            SendMessage(module, logLevel, file, line, function, format.substr(0, MaxLength));
        }
        else
        {
            std::array<std::uint8_t, MaxLength> fmtBuf;

            const auto endIt{fmt::format_to_n(
                fmtBuf.begin(),
                MaxLength,
                format,
                std::forward<Args>(args)...).out};

            const std::string_view formattedStr{
                reinterpret_cast<const char*>(fmtBuf.data()),
                static_cast<std::size_t>(std::distance(fmtBuf.begin(), endIt))};

            SendMessage(module, logLevel, file, line, function, formattedStr);
        }
    }
    catch (const std::exception& e)
    {
        details::PrintErrorMessage(file, line, e.what());
    }
}

} // namespace logrr

namespace {

const std::string_view LOG_MODULE;

} // namespace
#define __CPPLOG_LEVEL_TRACE__    logrr::LogLevel::Trace
#define __CPPLOG_LEVEL_DEBUG__    logrr::LogLevel::Debug
#define __CPPLOG_LEVEL_INFO__     logrr::LogLevel::Info
#define __CPPLOG_LEVEL_WARNING__  logrr::LogLevel::Warning
#define __CPPLOG_LEVEL_ERROR__    logrr::LogLevel::Error
#define __CPPLOG_LEVEL_CRITICAL__ logrr::LogLevel::Critical

#define LOG_INIT(providerName) \
    logrr::Init(providerName)

#define CALL_LOG(level, ...) \
    logrr::Log(LOG_MODULE, level, kos::rtl::SourceLocation::current(), __VA_ARGS__)

#define CALL_LOG_SL(level, file, line, func, ...) \
    logrr::Log(LOG_MODULE, level, file, line, func, __VA_ARGS__)

#define LOG(level, ...) CALL_LOG(__CPPLOG_LEVEL_ ## level ## __, __VA_ARGS__)
#define LOG_SL(level, file, line, func, ...) CALL_LOG_SL(__CPPLOG_LEVEL_ ## level ## __, file, line, func, __VA_ARGS__)

A macro for quick access to the Log() method

Instead of calling the static method Logger::Log(), you can use the macro whose description is provided in the file component/logrr/cpp/logger.h. This macro is variadic (takes a variable number of parameters), which lets you avoid specifying all parameters of the Logger::Log() method. When calling this macro, you only need to specify the log level and message formatting string with the values of parameters. The applied log level logLevel is determined by the first parameter of the macro: An example of using these macros is provided in the section titled Using macros to send messages to a log.

Article ID: logrr_api_cpp_log, Last review: Feb 20, 2025

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