Exit-time destructor warning in Clang

When writing C + +, if the front end is Clang then when you define a static global variable, a warning may appear called "Exit-time destructor".

As a habit of warning as the wrong look of the year, I determined to find out why this, and the result is this:

A global static variable calls its destructor after the program exits. Why not call it after the program exits? Because if the variable is destroyed during program execution, subsequent operations on that variable can cause a crash.

And the cost of destroying it after exiting is that it will cause the program to quit longer. And this warning is for you to point this out.

Exit-time destructor warning in Clang