fork创建一个进程

#include <stdio.h>
#include <unistd.h>
void son_process_handler(void);
void parent_process_handler(void);

int main(int argc,char ** argv) {
   pid_t pid;

   pid = fork();
   if(pid == 0){
       son_process_handler();
   }
   else{
       sleep(1);
       printf("new process ID : %d\n",pid);
       parent_process_handler();
   }

    return 0;
}
void son_process_handler(void){
    pid_t pid_tmp;

    printf("+-+-+-+-+-+- son process +-+-+-+-+-+-\n");
    pid_tmp = getpid();
    printf("the ID of the process is : %d\n",pid_tmp);
    pid_tmp = getppid();
    printf("the ID of the parent process is :%d\n",pid_tmp);
    pid_tmp = getuid();
    printf("the ID of the actural user is:%d\n",pid_tmp);
    pid_tmp = geteuid();
    printf("the ID of the effective user is :%d\n",pid_tmp);
    pid_tmp = getgid();
    printf("the ID of the actural group is:%d\n",pid_tmp);
    pid_tmp = getegid();
    printf("the ID of the effective group is:%d\n",pid_tmp);
    printf("+-+-+-+-+-+- son process +-+-+-+-+-+-\n");


}

void parent_process_handler(void){
    pid_t pid_tmp;

    printf("+-+-+-+-+-+- parent process +-+-+-+-+-+-\n");
    pid_tmp = getpid();
    printf("the ID of the process is : %d\n",pid_tmp);
    pid_tmp = getppid();
    printf("the ID of the parent process is :%d\n",pid_tmp);
    pid_tmp = getuid();
    printf("the ID of the actural user is:%d\n",pid_tmp);
    pid_tmp = geteuid();
    printf("the ID of the effective user is :%d\n",pid_tmp);
    pid_tmp = getgid();
    printf("the ID of the actural group is:%d\n",pid_tmp);
    pid_tmp = getegid();
    printf("the ID of the effective group is:%d\n",pid_tmp);
    printf("+-+-+-+-+-+- parent process +-+-+-+-+-+-\n");
}

输出

+-+-+-+-+-+- son process +-+-+-+-+-+-
the ID of the process is : 5750
the ID of the parent process is :5749
the ID of the actural user is:1000
the ID of the effective user is :1000
the ID of the actural group is:1000
the ID of the effective group is:1000
+-+-+-+-+-+- son process +-+-+-+-+-+-
new process ID : 5750
+-+-+-+-+-+- parent process +-+-+-+-+-+-
the ID of the process is : 5749
the ID of the parent process is :2330
the ID of the actural user is:1000
the ID of the effective user is :1000
the ID of the actural group is:1000
the ID of the effective group is:1000
+-+-+-+-+-+- parent process +-+-+-+-+-+-

Process finished with exit code 0