c ++ – Optimizing log function calls based on global logging level

I am a member of a university team that designs a nanosatellite.
We decided to implement our own (lighter) logging library to use, instead of, for example, that of Google. glog, spdlog, plog and Boost::Log.

  • The concept of different levels of logging is introduced, allowing log messages to be divided into subcategories based on their severity and eventuality.
  • In addition, a "global log level" can be defined.
    Anything less serious than the severity defined as global journal level do not to be connected.

Due to obvious restrictions, it is imperative that log calls below the global log level be optimized at compile time.

The first attempt looked like this (single header file):
log levels:

// We can set the global log level by defining one of these
#if defined LOGLEVEL_TRACE
#define LOGLEVEL Logger::trace
#elif defined LOGLEVEL_DEBUG
#define LOGLEVEL Logger::debug
#elif defined LOGLEVEL_INFO
#define LOGLEVEL Logger::disabled

the levels themselves are enum members:

enum LogLevel {
        trace = 32, // Very detailed information, useful for tracking the individual steps of an operation
        debug = 64, // General debugging information
        info = 96, // Noteworthy or periodical events

A operator<< overload for better readability:

Logger::LogEntry& operator<<(Logger::LogEntry& entry, const T value) {
    etl::to_string(value, entry.message, entry.format, true);

    return entry;

And the macroconstexpr ritual to make the compiler do what we want:

#define LOG(level)
    if (Logger::isLogged(level)) 
        if (Logger::LogEntry entry(level); true) 
// (...)
static constexpr bool isLogged(LogLevelType level) {
        return static_cast(LOGLEVEL) <= level;

There were a lot of problems with this code (see MR discussion for more).

  • An operator of call enum LogLevel has been added to return a new static LogEntry.
  • It is inlineto force const spread to -O1.
  • Two LogEntry enums has been created.
  • The second is a nop with all inline.
  • if constexpr the syntax has been added.

and more (see here and below for justification.)

It's the (hashed) state of the code currently:



#if defined LOGLEVEL_TRACE
#define LOGLEVEL Logger::trace
#elif defined LOGLEVEL_DEBUG
#define LOGLEVEL Logger::debug
#elif defined LOGLEVEL_INFO
#define LOGLEVEL Logger::info
#elif defined LOGLEVEL_NOTICE
#define LOGLEVEL Logger::notice
#elif defined LOGLEVEL_WARNING
#define LOGLEVEL Logger::warning
#elif defined LOGLEVEL_ERROR
#define LOGLEVEL Logger::error
#define LOGLEVEL Logger::emergency
#define LOGLEVEL Logger::disabled

#define LOG_TRACE     (LOG())
#define LOG_DEBUG     (LOG())
#define LOG_INFO      (LOG())
#define LOG_NOTICE    (LOG())
#define LOG_WARNING   (LOG())
#define LOG_ERROR     (LOG())

class Logger {

    Logger() = delete;

    typedef uint8_t LogLevelType;

    enum LogLevel : LogLevelType {
        trace = 32,
        debug = 64,
        info = 96,
        notice = 128,
        warning = 160,
        error = 192,
        emergency = 254,
        disabled = 255, 

    enum class NoLogEntry {};

    struct LogEntry {
        std::string message = "";
        LogLevel level;

        explicit LogEntry(LogLevel level);


        LogEntry(LogEntry const&) = delete;

        Logger::LogEntry& operator<<(const T value) noexcept {

            return *this;

        Logger::LogEntry& operator<<(const std::string& value);

    static constexpr bool isLogged(LogLevelType level) {
        return static_cast(LOGLEVEL) <= level;

    static void log(LogLevel level, std::string & message);

constexpr inline auto LOG() {
    if constexpr (Logger::isLogged(level)) {
        return Logger::LogEntry(level);
    } else {
        return Logger::NoLogEntry();

((maybe_unused)) constexpr Logger::NoLogEntry operator<<(const Logger::NoLogEntry noLogEntry, T value) {
    return noLogEntry;

int main() {
    LOG_NOTICE << "I am getting optimized away!";
    LOG_EMERGENCY << "I am not getting optimized away, and rightfully so";

    return 0;

As you can see in the compiler explorer, for example, LOG_NOTICE becomes optimized far from -O1.

Do you have any suggestions?

image quality – what is the global market value of Photo Booth

A Photo booth is a digital cash dispenser consisting of a camera and a film processor specifically used for capturing photographs for official documents and for entertainment purposes. In recent years, the photo booth market has developed thanks to its simple business model. Photo booths have become popular because of its adoption at weddings, parties, corporate events and government services.

Photo booths companies primarily offer rental services on an hourly basis, thus contributing significantly to the growth of the market. The main equipment required for the photo booth is the camera, background, accessories and other peripherals such as the printer and software, which reduces the investment needed to support many newcomers to the camera. market. Photo booths are mainly used to capture photos of official documents such as passports, driving licenses and other documents. On top of that, he has gained tremendous popularity in weddings, parties and another entertainment occasion, propelling the growth of the market.

Need help creating Sharepoint Global search Query URI

I'm trying to search for a file by passing a query text. When I try in a specific site with the help of https://graph.microsoft.com/v1.0/drives/b!l17-JY94D0CQp-2TBvsujaBLMUF2WrJHp5VylCDZThrZfpCdF-7uQ6MRp6t-MSRb/root/searchhr= well and i am able to get the answer with the name of the file. Since we have multiple sites and we want to search all sites when I try to perform a global search in all sites and drives with the help of http: // {server} / _api / search / query? Querytext = & # 39; sharepoint & # 39; Get the method, I do not receive any resposne. when I click Run Query in Graph API Eplorer, it does not load at all. Anyone can help me please about this.

global money drop | NewProxyLists

World monetary unit

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[ Global Warming ] Open question: In the last 70 years, which parts of the globe are not warming?

A recent question and the best answer about the warming "percentage" of the globe implied that it may only be a small area. There is a tool that lets you watch this, I played it a little bit and I found only places that cool (or stay the same) south of 70S – that is- to say in Antarctica. Can you find places on the rest of the globe that do not heat up? https://data.giss.nasa.gov/gistemp/stdata/ This is a real question and I really want to know the answer. I hoped that more people would use the link to find places that did not warm up. If you click on the link and scroll to the bottom of the page, you can click on the sites that enter the NASA GISS temperature and look directly at the stations. Our resident geologist could not even attempt to answer this question. He tells people that he is a scientist, but his answer is largely an uncontrollable, misleading political stalemate. . (tagsToTranslate) yahoo (t) answers (t) questions (t) Environment (t) Global warming

Geometry dg.differential – Transformation of coordinates of Poincaré into global coordinates in $ mathrm {AdS} _2 $

For two-dimensional anti-sitter space $ mathrm {AdS} _2 $ we can consider the coordinates of Poincaré $ mathrm {d} s ^ 2_P = -r ^ 2 mathrm {d} t ^ 2 + frac {1} {r ^ 2} mathrm {d} r ^ 2 $ which only covers half of the space-time. Most of the time, we use global coordinates $ mathrm {d} s ^ 2_ {G1} = – (1 + r ^ 2) mathrm {d} t ^ 2 + frac {1} {1 + r ^ 2} mathrm {d} r ^ 2 $, or the latter with an additional transformation $ r = mathrm {sinh} ( rho) $: $ mathrm {d} s ^ 2_ {G2} = – mathrm {cosh} ( rho) mathrm {d} t ^ 2 + mathrm {d} rho ^ 2 $. This question seems to be more trivial, but what is the explicit transformation of the coordinates of $ mathrm {d} s ^ 2_P $ is $ mathrm {d} s ^ 2_ {G1} $ or $ mathrm {d} s ^ 2_ {G2} $?

dnd 3.5e – For damage due to falling objects, does the maximum of 20d6 apply only to additional damage caused by distance, or is it? a global maximum?

According to the DMG, page 303:

For 200 pounds of an item's weight, it deals 1d6 damage, as long as it falls at least 10 feet. The distance also comes into play, adding 1d6 additional damage for each 10-foot increment falling beyond the first (up to a maximum of 20d6 points of damage).

I read that it meant that the damage added by the distance of the hats dropped to 20d6, but that the damage based on the weight of the object had no hat.

One of my friends said that it remembers a lot of talk about the subject years ago and a decision that the damage caused by the fall of an object has a strict ceiling of 20d6, regardless extra weight.

Unfortunately, he can not find where the things he remembers have been told, and all we need to go on is the text of the book. Does anyone know what is the correct answer? Preferably with a source?

your comments on global IP networks (gipnetworks.com)

For many years on the hosting industry, we have finally started buying our own servers. We chose Global Ip Networks for the roommate and I want to say that the first month everything looks great! High speed, great meeting with the CEO (Reyner) and his team. I will update this post a few months later.

At this moment five stars

Thank you!

True or false: do you like to discuss global warming with your mother?

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