了解Unix进程(3)

fork() 系统调用能够建立新的进程。而后查看进程ID和父进程ID使用getpid()和getppid()函数.

使用C语言描述:

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

int 
main (int argc, char *argv[])
{
    pid_t child = -1;
    
    if ((child = fork()) == 0) {
        fprintf(stderr, "1: child pid is %u\n", getpid());
        fprintf(stderr, "2: his parent is %u\n", getppid());
    } else {
        fprintf(stderr, "3: parent pid is %u\n", getpid());
    }
    return 0;
}

运行结果: