[Linux]Linux子进程的执行起点

文章目录[隐藏]

程序
结果分析
结论

程序

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

int main(void){
    printf("main pid: %d\n-------------\n", getpid());
    printf("\n------main do fork1------\n\n");
    int pid = fork();
    printf("fork1 result: %d\n", getpid());
    if(pid > 0){
        // 父进程
        printf("main thread current pid: %d\n\n", getpid());
        exit(0);
    }else{
        // 子进程
        printf("child1 pid: %d\n", getpid());

        pid_t sid = setsid();

        printf("\n------child1 do fork2------\n\n");
        pid = fork();
        printf("fork2 result: %d\n", getpid());
        if(pid == 0){
            printf("child2 pid: %d\n", getpid());
        }else{
            printf("child1 pid: %d\n", getpid());
        }
        exit(0);
    }
}