C++17 static_assert

发表于

C++17中新增了static_assert，即静态断言，在编译期就能帮助程序员识别到代码中的一些断言错误, 并且可以在static_assert中加入第二个参数，将字符串直接作为编译结果输出

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
#include <iostream>

using namespace std;

int main ( ) {
        //Until C++14
        MyClass<int, double> obj1;
        obj1.printSizeOfDataTypes( );
        //New syntax in C++17
        MyClass obj2( 1, 10.56 );
        
        const int x = 5, y = 5;
        static_assert ( 1 == 0, "Assertion failed" );
        static_assert ( 1 == 0 );
        static_assert ( x == y );

        return 0;
}

1
2
3
4
5
6
7
8
$ g++ test1.cc -std=c++17
test1.cc: In function ‘int main()’:
test1.cc:28:27: error: static assertion failed: Assertion failed
   28 |         static_assert ( 1 == 0, "Assertion failed" );
      |                         ~~^~~~
test1.cc:29:27: error: static assertion failed
   29 |         static_assert ( 1 == 0 );
      |