How do I execute a statement before the main () function in C + +?

In the C language, if you use GCC, you can declare constructor and destructor with the attribute keyword (how to execute a function before the main function starts in the C language)

#include <stdio.h>__attribute((Constructor))voidBefore_main(){Printf("%s/n",__function__);}__attribute ((destructor) void after_main () {printf (  "%s/n" ,__function__); } int main (int  Argcchar ** argv ) {printf ( "%s/n"  __function__); return 0               /span>                

In C + +, using the attributes of global variables and constructors, the constructor of a global variable executes (how C + + language executes a piece of code before the main function executes)

#include <Iostream>UsingNamespaceStd;ClassTestClass{publictestclass (); }; testclass::testclass () { cout<< "TestClass" << endl;} testclass ts; Define a global variable so that the code inside the class executes before main int main () { cout<< "main" <<endl return 0;}        

How do I execute a statement before the main () function in C + +?