diffork.c

#include<stdio.h>
#include<sys/types.h>
#include<unistd.h>
#include<stdlib.h>

int globvar = 5;

int main(void)
{
    pid_t pid;
    int var = 1, i;

    printf("fork is different with vfork\n");
    
      pid = fork();
     // pid = vfork();
    switch(pid){
        case 0:
                i = 3;
        while(i-- > 0){
            printf("Child process is running\n");
            globvar++;
            var++;
            sleep(1);
        }
        printf("child‘s globvar = %d, var = %d\n", globvar, var);
        break;
        case -1:
                printf("error\n");
                exit(0);
        default:
                i = 5;
        while(i-- > 0){
            printf("parent process is running\n");
            globvar++;
            var++;
            sleep(1);
        }
        printf("parent‘s globvar = %d, var = %d\n", globvar, var);
        exit(0);
    }
}