UNIX编程(9)-进程关系

1.终端登录

2.网络登录

3.进程组

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#include <unistd.h>pid_t getpgrp(void);

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Returns: process group ID of calling process

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#include <unistd.h>pid_t getpgid(pid_t pid);

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Returns: process group ID if OK, 1 on error

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#include <unistd.h>int setpgid(pid_t pid, pid_t pgid);

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Returns: 0 if OK, 1 on error

建立会话

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#include <unistd.h>pid_t setsid(void);

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Returns: process group ID if OK, 1 on error

返回会话的首进程的进程组ID

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#include <unistd.h>pid_t getsid(pid_t pid);

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

5.控制终端

6.tcgetpgrp,tcsetpgrp?和tcgetsid函数

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#include <unistd.h>pid_t tcgetpgrp(int filedes);

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

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int tcsetpgrp(int filedes, pid_t pgrpid);

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Returns: 0 if OK, 1 on error

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#include <termios.h>pid_t tcgetsid(int filedes);

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

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 voidsig_hup(int signo){    printf("SIGHUP received, pid = %d\n", getpid());}static voidpr_ids(char *name){    printf("%s: pid = %d, ppid = %d, pgrp = %d, tpgrp = %d\n",        name, getpid(), getppid(), getpgrp(), tcgetpgrp(STDIN_FILENO));    fflush(stdout);}intmain(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);     }}

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