进程串

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
int main(){
        int p1,p2,p3,p4;
        while((p1=fork())==-1);
        if(p1==0){

        printf("child %d parent %d\n",getpid(),getppid());
                while((p2=fork())==-1);
                if(p2==0){
                // child process        
                        printf("child %d parent %d\n",getpid(),getppid());
                        while((p3=fork())==-1);
                        if(p3==0){
                                printf("child %d parent %d\n",getpid(),getppid());
                                while((p4=fork())==-1);
                        }
                }
        }

                                //printf("child %d parent %d\n",getpid(),gitppid());
        return 0;
}

~                                                                                                                                   
~                      

 进程树

#include <stdio.h>
#include <unistd.h>

int main(){
        int p1,p2,p3,p4,p5,p6;

        while((p4=fork())<0);
        while((p1=fork())<0);
        if(p1==0){
                printf("child %d parent %d\n",getpid(),getppid());
                while((p2=fork())<0);
                if(p2==0){
                        printf("child %d parent %d\n",getpid(),getppid());
                        while((p3=fork())<0);
                        if(p3==0){
                                printf("child %d parent %d\n",getpid(),getppid());
                        }
                }
        }
// 如果不是else 则发现会子进程执行
        else if(p4==0){
                printf("child %d parent %d\n",getpid(),getppid());
                while((p5=fork())<0);
                if(p5==0){
                        printf("child %d parent %d\n",getpid(),getppid());
                }
                while((p6=fork())<0);
                if(p5==0){
                        printf("child %d parent %d\n",getpid(),getppid());
                }
        }

        return 0;
}