Mastering C++ Programming

Simplified static_assert 

The static_assert macro helps identify assert failures during compile time. This feature has been supported since C++11; however, the static_assert macro used to take a mandatory assertion failure message till, which is now made optional in C++17.

The following example demonstrates the use of static_assert with and without the message:

#include <iostream>#include <type_traits>using namespace std;int main ( ) {        const int x = 5, y = 5;        static_assert ( 1 == 0, "Assertion failed" );        static_assert ( 1 == 0 );        static_assert ( x == y );        return 0;}

The output of the preceding program is as follows:

g++-7 staticassert.cpp -std=c++17staticassert.cpp: In function ‘int main()’:staticassert.cpp:7:2: error: static assertion failed: ...