Avoiding compiler issues with abs()

Question

When using the double variant of the std::abs() function without the std with g++ 4.6.1, no warning or error is given.

Answer 1

Be warned, you don't need to explicitly #include , does the damage as well (and maybe some other headers). Also, note that -Wall doesn't give you any warnings about it.

#include 

int main() {
  std::cout << abs(.5) << std::endl;
  std::cout << typeid(decltype(abs)).name() << std::endl;
}

Gives output

0
FiiE

On

gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04)