UNIX编程(9)-进程关系

1.终端登录

2.网络登录

3.进程组

 

#include <unistd.h>

pid_t getpgrp(void);

 

Returns: process group ID of calling process

 

#include <unistd.h>

pid_t getpgid(pid_t pid);

 

Returns: process group ID if OK, 1 on error

 

#include <unistd.h>

int setpgid(pid_t pid, pid_t pgid);

 

Returns: 0 if OK, 1 on error

4.会话

建立会话

 

#include <unistd.h>

pid_t setsid(void);

 

Returns: process group ID if OK, 1 on error

返回会话的首进程的进程组ID

 

 

#include <unistd.h>

pid_t getsid(pid_t pid);

 

Returns: session leader's process group ID if OK, 1 on error

5.控制终端

6.tcgetpgrp,tcsetpgrp 和tcgetsid函数

 

 

 

#include <unistd.h>

pid_t tcgetpgrp(int filedes);

 

Returns: process group ID of foreground process group if OK, 1 on error

 

int tcsetpgrp(int filedes, pid_t pgrpid);

 

Returns: 0 if OK, 1 on error

 

#include <termios.h>

pid_t tcgetsid(int filedes);

 

Returns: session leader's process group ID if OK, 1 on error

7.作业控制

8.shell执行程序

9.孤儿进程组

例：

创建一个孤儿进程组

#include "apue.h"
#include <errno.h>

static void
sig_hup(int signo)
{
    printf("SIGHUP received, pid = %d\n", getpid());
}

static void
pr_ids(char *name)
{
    printf("%s: pid = %d, ppid = %d, pgrp = %d, tpgrp = %d\n",
        name, getpid(), getppid(), getpgrp(), tcgetpgrp(STDIN_FILENO));
    fflush(stdout);
}

int
main(void)
{
     char     c;
     pid_t    pid;

     pr_ids("parent");
     if ((pid = fork()) < 0) {
         err_sys("fork error");
     } else if (pid > 0) {   /* parent */
         sleep(5);       /*sleep to let child stop itself */
         exit(0);        /* then parent exits */
     } else {            /* child */
         pr_ids("child");
         signal(SIGHUP, sig_hup);    /* establish signal handler */
         kill(getpid(), SIGTSTP);    /* stop ourself */
         pr_ids("child");    /* prints only if we're continued */
         if (read(STDIN_FILENO, &c, 1) != 1)
             printf("read error from controlling TTY, errno = %d\n",
                 errno);
         exit(0);
     }
}