独立于main运行的程序

#include <iostream>
using namespace std;
#define INITIALIZER(f) \
    static void f(void) __attribute__((constructor)); \
    static void f(void)
#define DEINITIALIZER(f) \
    static void f(void) __attribute__((destructor)); \
    static void f(void)



static void IniFunc(){
    int a = 1+1; 
    printf("func()---1+1= %d\n",a);
    printf("func()---can not use std::cout \n");
    //cout<<"func()"<<endl;
    
}
static void deFunc(){
    cout<<"~func()"<<endl;
    int a = 1+2; 
    printf("1+2= %d\n",a);
    std::cout<<"std::cout"<<std::endl;
}
INITIALIZER(ff){
    IniFunc();
};

DEINITIALIZER(dd){
    deFunc();
    std::cout<<"can use cout"<<std::endl;
};

/*
static void f1(void) __attribute__((constructor)); 

void f1(void){
     printf("before main1111\n");
}
*/
/*
void static __attribute__((constructor)) before_main()
{
    printf("before main\n");
}

void static __attribute__((destructor)) after_main()
{
    printf("after main\n");

}
*/

int main(){

cout<< "in main"<<endl;
return 0;
}

ygy@ygy-VirtualBox:~/work/tmp$ g++ d.cpp 
ygy@ygy-VirtualBox:~/work/tmp$ ./a.out 
func()---1+1= 2
func()---can not use std::cout 
in main
~func()
1+2= 3
std::cout
can use cout