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static-print

Changelog

• 4/7/17 - Fixed issue which prevented the compiler from compiling during second stage (bootstrapping).

What is it

This is a patch to the GCC 7.1 source which adds a "static_print" statement to C++.

The static_print statement can be used wherever static_assert can be used, and its effect is to print a formatted message at compile time.

static_print can receive any no. of arguments, each argument being either a string literal (which is printed out), or any "template-argument" expression (anything that could be a template argument - types, constant expressions, template names, etc..), which is resolved at compile time and pretty-printed.

Unlike static_assert, static_print also behaves correctly with if constexpr! (nothing will be printed if the condition does not apply).

Example

template<typename T, int s>
struct test
{
    static_print("The template ", ::test, " has been instantiated as ", test, ". By the way, s + 1 is ", s + 1);
};

int main() {
    test<int, 3> y;
    return 0;
}

Compiling the above program prints out (at compile time): The template test has been instantiated as test<int, 3>. By the way, s + 1 is 4

How to use

Download the GCC 7.1 sources, apply the patch and build GCC for your platform of choice