Item 10 - static_assert (English)

static_assert

static_assert is a keyword introduced in C++11 for performing assertion checks at compile-time. If the condition is not satisfied, it generates an error during compilation. This is particularly useful for checking static invariant conditions or assertions, especially in functions related to templates.

Main idea

The main idea is to detect issues at compile-time whenever possible, minimizing the time required for fixing them.

Problems encountered during runtime might be related to external data or environments. Even after making corrections, one would need to rerun the program to confirm the fixes, consuming a significant amount of time.

Of course, having unit tests in your project can also reduce the time spent on fixing bugs.

Examples where static_assert is not suitable In fact, similar to constexpr, static_assert performs checks during compilation, so the situations where it is not suitable are also the same.

1. Cases where decisions are made dynamically at runtime: Since static_assert performs assertion checks at compile-time, it cannot be used for conditions that depend on external factors at runtime.

2. Situations depending on external states: If the conditions for assertion checks depend on external states, such as system status or user input, static_assert cannot be used because it operates at compile-time.

3. Conditions that are overly complex: If the conditions for assertion checks are too complex to be statically evaluated at compile-time, static_assert cannot be used. It is suitable only for simple conditions that can be evaluated statically during compilation.

template <typename T>
void process_data(T data) {
    static_assert(std::is_integral<T>::value, "Can only process integral types");

    // Processing data of integral types
    std::cout << "Processing data..." << std::endl;
}

int main()
{
    process_data(5);  // Correct, because the parameter is of integral type
    process_data(1.1);  // Error, because the parameter is of floating-point type, which will cause the static_assert to fail

    return 0;
}

Result