There are a number of text conventions used throughout this book.

constexpr: Indicates code words in text, numbers, folder names, filenames, file extensions, pathnames, dummy URLs, and user input. Here is an example: "The noexcept specifier is used to tell the compiler whether a function may or may not throw a C++ exception."

A block of code is set as follows:

int main(void)
{
    the_answer is;
    return 0;
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

int main(void)
{
    auto execute_on_exit = finally{[]{
        std::cout << "The answer is: 42
";
    }};
}

Any command-line input or output is written as follows:

> mkdir build && cd build
> cmake ..
> make recipe04_examples

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, important words appear in the text like this. Here is an example: "In this recipe, we will learn why throwing exceptions in a destructor is a bad idea."