進(jìn)程間的通信

1、進(jìn)程間通信(1)調(diào)試以下程序給出運(yùn)行結(jié)果并分析其程序原理：#include <stdio.h>#include <unistd.h>#include <wait.h>#include <signal.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>（1）編寫(xiě)兩個(gè)程實(shí)現(xiàn)進(jìn)程的無(wú)名管道和有名管道通信。要求分別調(diào)用pipe()、close()、write()、read()、popen()、p

2、close()、mknod()、mkfifo()、open()實(shí)現(xiàn)多個(gè)進(jìn)程間的通信。1.使用無(wú)名管道pipe()，進(jìn)行父子進(jìn)程之間的通信。編寫(xiě)的程序如下：運(yùn)行結(jié)果：2.以命名行為參數(shù)的管道文件的示例。(假設(shè)有一個(gè)可執(zhí)行程序chcase，從標(biāo)準(zhǔn)輸入設(shè)備讀字符，將小寫(xiě)字母轉(zhuǎn)化成大寫(xiě)字母并輸出。主程序使用popen創(chuàng)建管道，實(shí)現(xiàn)蔣某文本文件中的字幕轉(zhuǎn)化成大寫(xiě)字母，其中的文本文件名作為參數(shù)傳進(jìn)來(lái)。)Text.c文件 運(yùn)行結(jié)果：3.創(chuàng)建有名管道。運(yùn)行結(jié)果4.軟中斷機(jī)制#include<stdio.h>#include<signal.h>#include<unistd.h&g

3、t; void waiting(),stop(),alarming();int wait_mark;main()int p1,p2;if(p1=fork() /*創(chuàng)建子進(jìn)程p1*/if(p2=fork() /*創(chuàng)建子進(jìn)程p2*/wait_mark=1;signal(SIGINT,stop); /*接收到c信號(hào)，轉(zhuǎn)stop*/signal(SIGALRM,alarming);/*接受SIGALRMwaiting();kill(p1,16); /*向p1發(fā)軟中斷信號(hào)16*/ kill(p2,17); /*向p2發(fā)軟中斷信號(hào)17*/ wait(0); /*同步*/wait(0);printf(&qu

4、ot;parent process is killed!n");exit(0); else wait_mark=1;signal(17,stop);signal(SIGINT,SIG_IGN); /*忽略 c信號(hào)*/while (wait_mark!=0);lockf(1,1,0);printf("child process2 is killed by parent!n");lockf(1,0,0);exit(0);elsewait_mark=1;signal(16,stop);signal(SIGINT,SIG_IGN); /*忽略c信號(hào)*/while (wai

5、t_mark!=0)lockf(1,1,0);printf("child process1 is killed by parent!n");lockf(1,0,0);exit(0);void waiting()sleep(5);if (wait_mark!=0) kill(getpid(),SIGALRM);void alarming()wait_mark=0;void stop()wait_mark=0;運(yùn)行結(jié)果：5.信號(hào)程序?qū)嵗c修正#include <stdio.h>#include <signal.h>#include <unistd.

6、h>void waiting( ),stop( );int wait_mark;main( )int p1,p2,stdout;while(p1=fork( )= =-1); /*創(chuàng)建子進(jìn)程p1*/if (p1>0) while(p2=fork( )= =-1); /*創(chuàng)建子進(jìn)程p2*/if(p2>0) wait_mark=1;signal(SIGINT,stop); /*接收到c信號(hào)，轉(zhuǎn)stop*/waiting( );kill(p1,16); /*向p1發(fā)軟中斷信號(hào)16*/kill(p2,17); /*向p2發(fā)軟中斷信號(hào)17*/wait(0); /*同步*/wait(0)

7、;printf("Parent process is killed!n");exit(0); else wait_mark=1;signal(17,stop); /*接收到軟中斷信號(hào)17，轉(zhuǎn)stop*/waiting( );lockf(stdout,1,0);printf("Child process 2 is killed by parent!n");lockf(stdout,0,0);exit(0);elsewait_mark=1;signal(16,stop); /*接收到軟中斷信號(hào)16，轉(zhuǎn)stop*/waiting( );lockf(stdout

8、,1,0);printf("Child process 1 is killed by parent!n");lockf(stdout,0,0);exit(0); void waiting( ) while(wait_mark!=0);void stop( )wait_mark=0;運(yùn)行結(jié)果屏幕上無(wú)反應(yīng)，按下C后，顯示 Parent process is killed!分析原因 思考1、 該程序段前面部分用了兩個(gè)wait(0)，它們起什么作用？ 用了兩個(gè)wait(0)的作用是父進(jìn)程等待兩個(gè)子進(jìn)程終止2、 該程序段中每個(gè)進(jìn)程退出時(shí)都用了語(yǔ)句exit(0)，為什么？ 用exit（

9、0）的作用是使子進(jìn)程實(shí)現(xiàn)正常終止，正常退出此次操作，返回。 3、 為何預(yù)期的結(jié)果并未顯示出？ 因?yàn)橹粓?zhí)行成功兩個(gè)子進(jìn)程，但是并沒(méi)有調(diào)用兩個(gè)子進(jìn)程P1,P2。當(dāng)signal()讓父進(jìn)程捕捉從鍵盤(pán)上來(lái)的信號(hào)（按下C或者break鍵時(shí)），只有捕捉到信號(hào)后，父進(jìn)程用系統(tǒng)調(diào)用kill（）向兩個(gè)子進(jìn)程發(fā)出信號(hào)。當(dāng)子進(jìn)程捕捉到信號(hào)后才能輸出信息，之后父進(jìn)程輸出信息。 4、（重點(diǎn)）程序該如何修改才能得到正確結(jié)果？（實(shí)驗(yàn)報(bào)告中寫(xiě)出完整程序）#include <stdio.h>#include <unistd.h>#include <wait.h>#include <si

10、gnal.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>void waiting( ),stop( );int wait_mark;int main( )int p1,p2,stdout;while(p1=fork()=-1); /*創(chuàng)建子進(jìn)程p1*/if (p1>0) while(p2=fork()=-1); /*創(chuàng)建子進(jìn)程p2*/if(p2>0) wait_mark=1;signal(SIGINT,stop)

11、; /*接收到c信號(hào)，轉(zhuǎn)stop*/waiting();kill(p1,16); /*向p1發(fā)軟中斷信號(hào)16*/kill(p2,17); /*向p2發(fā)軟中斷信號(hào)17*/wait(0); /*同步*/wait(0);printf("Parent process is killed!n");exit(0); else wait_mark=1;signal(17,stop); /*接收到軟中斷信號(hào)17，轉(zhuǎn)stop*/signal(SIGINT,SIG_IGN);/修改處waiting( );lockf(stdout,1,0);printf("Child process 2 is killed by parent!n");lockf(stdout,0,0);exit(0);elsewait_mark=1;signal(16,stop); /*接收到軟中斷信號(hào)16，轉(zhuǎn)stop*/signal(SIGINT,SIG_IGN);/修改處waiting();lockf(stdout,1,0);