#include <stdio.h>

// Before attribute
#define BEFORE_ATR __attribute__((constructor))
// After attribute
#define AFTER_ATR __attribute__((destructor))

void BEFORE_ATR beforeFunc() { printf("Executed before main\n"); }
void AFTER_ATR afterFunc() { printf("Executed after main\n"); }

int main(void) { printf("Executed in main\n"); }