C 父级如何在每个子级和自身之间创建管道，以及每个子级如何通过管道向父级发送字数
我编写的代码通过创建多个进程来计算多个文本文件中的字数，每个进程负责一个文件来计算字数 我想做的是使用管道找出所有文件中的总字数 因此，家长应：C 父级如何在每个子级和自身之间创建管道，以及每个子级如何通过管道向父级发送字数,c,operating-system,filesystems,pipe,fork,C,Operating System,Filesystems,Pipe,Fork,我编写的代码通过创建多个进程来计算多个文本文件中的字数，每个进程负责一个文件来计算字数 我想做的是使用管道找出所有文件中的总字数 因此，家长应： 在每个子级和它自身之间创建一个管道，以便它可以从每个子级获取字数 通过添加通过管道接收的数字，报告所有文件中的总字数 检查每个子项的退出状态并打印出该子项如何退出 退出 也让每个孩子： 通过管道将字数发送给父级 如果文件没有，则通过管道将0作为字数发送到父级 不存在或发生任何其他错误 如果成功打开文件并返回，则返回/退出0 计算该文件中的字数，如
#包括
#包括
#包括
#包括
#定义最大字符100
pid_t getpid（无效）；
pid_t getppid（无效）；
字符*itoa（整数i，字符b[]{
字符常量数字[]=“0123456789”；
char*p=b；
如果（i=0）{
printf（“用于%s的子进程pid\ud：字数为%d\n”，i，arvg[i]，字）；
//我不知道如何在管道中写入int，因此下面可能是错误的
书写（*书写单词，1）；
返回0；
}else if（单词==-1）{
printf（“用于%s的子进程pid_u%d:不存在”\n“，i，arvg[i]）；
//我不知道如何在管道中写入int，因此下面可能是错误的
书写（标准文件号，单词，1）；
出口（1）；
}
}否则{
关闭（*write_fd）；
//我不知道如何从管道中读取int
read（*read_fd和readbuffer，1）；
totalwords+=？？？
关闭（*read_fd）；
//等待所有子进程退出/返回
如果（ppid==getpid（））{
等待（&状态）；
}
//检查它们的退出代码，WEXITSTATUS=子级退出时返回代码
if（WEXITSTATUS（status）==1）{
计数++；
}
}
}
printf（“主进程创建了%d个子进程来计算%d个文件中的字\n”，argc-1，argc-1）；
printf（“总字数为%d”，总字数）；
printf（“%d个文件已成功计数！\n”，argc-1-count）；
printf（“%d个文件不存在。\n”，计数）；
返回0；
}```
有人能帮我弄清楚吗？我真的不知道如何用烟斗达到我的目标。
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>
#define MAX_CHAR 100
pid_t getpid(void);
pid_t getppid(void);
char* itoa(int i, char b[]){
char const digit[] = "0123456789";
char* p = b;
if(i<0){
*p++ = '-';
i *= -1;
}
int shifter = i;
do{ //Move to where representation ends
++p;
shifter = shifter/10;
}while(shifter);
*p = '\0';
do{ //Move back, inserting digits as u go
*--p = digit[i%10];
i = i/10;
}while(i);
return b;
}
int countWords(char * fp, int pid) {
FILE * file;
int words = 0;
char word[MAX_CHAR];
//execute this function only if child process of parent, no gradchild is allowed to execute this function!
if (pid == getppid()) {
file = fopen(fp, "r");
if (file == NULL) {
return -1;
}
//find string in the file and count the words.
while (fscanf(file, "%s", word) != EOF) {
words++;
}
return words;
} else {
return -1;
}
return 0;
}
int main(int argc, char * arvg[]) {
//if invalid arguments
if (argc < 2) {
fprintf(stderr, "ERROR: INVALID ARGUMENTS");
exit(-1);
}
int count = 0, pid, ppid, status, totalwords = 0;
int result = -1;
int fd[2];
char string[100];
char readbuffer[80];
int *write_fd = &fd[1];
int *read_fd = &fd[0];
int recvd = 0;
result = pipe(fd);
if(-1 == result){
perror("pipe");
return -1;
}
//creates (argc - 1) child processes using fork()
//pid = (int) malloc((argc - 1) * sizeof(int));
//parent pid
ppid = getpid();
//each child process to count the number of words in each file
for (int i = 1; i < argc; i++) {
//child process
pid = fork();
if( pid == -1){
perror("failed to fork");
return -1;
}else if (pid == 0) {
printf ("%d child running \n", i);
// call a function to count the number of words in file arvg[i]
int words = countWords(arvg[i], ppid);
close(*read_fd);
if (words >= 0) {
printf("Child process pid_%d for %s :number of words is %d\n", i, arvg[i], words);
//I don't know how to write int into the pipe,so below might be wrong
write(*write_fd, (void *)&words, 1);
return 0;
} else if (words == -1) {
printf("Child process pid_%d for %s :does not exists\n", i, arvg[i]);
//I don't know how to write int into the pipe,so below might be wrong
write(STDOUT_FILENO, (void *)&words, 1);
exit(1);
}
} else {
close(*write_fd);
//and I have no idea how to read int from pipes
read(*read_fd, (void*)&recvd, 1);
totalwords += recvd;
printf("recvd %d \n", totalwords);
close(*read_fd);
//Wait until all child processes exit/return
if (ppid == getpid()) {
wait( & status);
}
//inspect their exit codes, WEXITSTATUS = return code when child exits
if (WEXITSTATUS(status) == 1) {
count++;
}
}
}
printf("Main process created %d child processes to count words in %d files\n", argc - 1, argc - 1);
printf("Total words is %d\n", totalwords);
printf("%d files have been counted sucessfully!\n", argc - 1 - count);
printf("%d files did not exist.\n", count);
return 0;
}
#包括
#包括
#包括
#包括
#包括
#定义最大字符100
pid_t getpid（无效）；
pid_t getppid（无效）；
字符*itoa（整数i，字符b[]{
字符常量数字[]=“0123456789”；
char*p=b；
如果（i=0）{
printf（“用于%s的子进程pid\ud：字数为%d\n”，i，arvg[i]，字）；
//我不知道如何在管道中写入int，因此下面可能是错误的
书写（*书写（无效*）和文字，1）；
返回0；
}else if（单词==-1）{
printf（“用于%s的子进程pid_u%d:不存在”\n“，i，arvg[i]）；
//我不知道如何在管道中写入int，因此下面可能是错误的
书写（标准文件号（void*）和单词，1）；
出口（1）；
}
}否则{
关闭（*write_fd）；
//我不知道如何从管道中读取int
read（*read_fd，（void*）和recvd，1）；
totalwords+=recvd；
printf（“记录%d\n”，totalwords）；
关闭（*read_fd）；
//等待所有子进程退出/返回
如果（ppid==getpid（））{
等待（&状态）；
}
//检查它们的退出代码，WEXITSTATUS=子级退出时返回代码
if（WEXITSTATUS（status）==1）{
计数++；
}
}
}
printf（“主进程创建了%d个子进程来计算%d个文件中的字\n”，argc-1，argc-1）；
printf（“总字数为%d\n”，总字数）；
printf（“%d个文件已成功计数！\n”，argc-1-count）；
printf（“%d个文件不存在。\n”，计数）；
返回0；
}
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>
#define MAX_CHAR 100
pid_t getpid(void);
pid_t getppid(void);
char* itoa(int i, char b[]){
char const digit[] = "0123456789";
char* p = b;
if(i<0){
*p++ = '-';
i *= -1;
}
int shifter = i;
do{ //Move to where representation ends
++p;
shifter = shifter/10;
}while(shifter);
*p = '\0';
do{ //Move back, inserting digits as u go
*--p = digit[i%10];
i = i/10;
}while(i);
return b;
}
int countWords(char * fp, int pid) {
FILE * file;
int words = 0;
char word[MAX_CHAR];
//execute this function only if child process of parent, no gradchild is allowed to execute this function!
if (pid == getppid()) {
file = fopen(fp, "r");
if (file == NULL) {
return -1;
}
//find string in the file and count the words.
while (fscanf(file, "%s", word) != EOF) {
words++;
}
return words;
} else {
return -1;
}
return 0;
}
int main(int argc, char * arvg[]) {
//if invalid arguments
if (argc < 2) {
fprintf(stderr, "ERROR: INVALID ARGUMENTS");
exit(-1);
}
int count = 0, pid, ppid, status, totalwords = 0;
int result = -1;
int fd[2];
char string[100];
char readbuffer[80];
int *write_fd = &fd[1];
int *read_fd = &fd[0];
int recvd = 0;
result = pipe(fd);
if(-1 == result){
perror("pipe");
return -1;
}
//creates (argc - 1) child processes using fork()
//pid = (int) malloc((argc - 1) * sizeof(int));
//parent pid
ppid = getpid();
//each child process to count the number of words in each file
for (int i = 1; i < argc; i++) {
//child process
pid = fork();
if( pid == -1){
perror("failed to fork");
return -1;
}else if (pid == 0) {
printf ("%d child running \n", i);
// call a function to count the number of words in file arvg[i]
int words = countWords(arvg[i], ppid);
close(*read_fd);
if (words >= 0) {
printf("Child process pid_%d for %s :number of words is %d\n", i, arvg[i], words);
//I don't know how to write int into the pipe,so below might be wrong
write(*write_fd, (void *)&words, 1);
return 0;
} else if (words == -1) {
printf("Child process pid_%d for %s :does not exists\n", i, arvg[i]);
//I don't know how to write int into the pipe,so below might be wrong
write(STDOUT_FILENO, (void *)&words, 1);
exit(1);
}
} else {
close(*write_fd);
//and I have no idea how to read int from pipes
read(*read_fd, (void*)&recvd, 1);
totalwords += recvd;
printf("recvd %d \n", totalwords);
close(*read_fd);
//Wait until all child processes exit/return
if (ppid == getpid()) {
wait( & status);
}
//inspect their exit codes, WEXITSTATUS = return code when child exits
if (WEXITSTATUS(status) == 1) {
count++;
}
}
}
printf("Main process created %d child processes to count words in %d files\n", argc - 1, argc - 1);
printf("Total words is %d\n", totalwords);
printf("%d files have been counted sucessfully!\n", argc - 1 - count);
printf("%d files did not exist.\n", count);
return 0;
}
#包括
#包括
#包括
#包括
#包括
#定义最大字符100
pid_t getpid（无效）；
pid_t getppid（无效）；
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>
#define MAX_CHAR 100
pid_t getpid(void);
pid_t getppid(void);
char* itoa(int i, char b[]){
char const digit[] = "0123456789";
char* p = b;
if(i<0){
*p++ = '-';
i *= -1;
}
int shifter = i;
do{ //Move to where representation ends
++p;
shifter = shifter/10;
}while(shifter);
*p = '\0';
do{ //Move back, inserting digits as u go
*--p = digit[i%10];
i = i/10;
}while(i);
return b;
}
// count word from file provided
int countWords(char * fp, int pid) {
FILE * file;
int words = 0;
char word[MAX_CHAR];
//execute this function only if child process of parent, no gradchild is allowed to execute this function!
if (pid == getppid()) {
file = fopen(fp, "r");
if (file == NULL) {
return -1;
}
//find string in the file and count the words.
while (fscanf(file, "%s", word) != EOF) {
words++;
}
return words;
} else {
return -1;
}
return 0;
}
//do everything related to child here in this function
void child_process(int write_fd, char *filename, int ppid)
{
// call a function to count the number of words in file argv[i]
printf("counting words of %s\n", filename);
int words = countWords(filename, ppid);
if (words >= 0) {
printf("Child process pid for %s :number of words is %d\n", filename, words);
write(write_fd, (void *)&words, 1);
close(write_fd);
exit(0);
} else if (words == -1) {
printf("Child process pid for %s :does not exist\n", filename);
write(STDOUT_FILENO, (void *)&words, 1);
close(write_fd);
exit(1);
}
return;
}
int main(int argc, char * argv[]) {
//if invalid arguments
if (argc < 2) {
fprintf(stderr, "ERROR: INVALID ARGUMENTS");
exit(-1);
}
int pid = 0;
int ppid = 0;
int totalwords = 0;
int fd[2] = {0};
int write_fd = 0;
int read_fd = 0;
int recvd = 0;
// open a pipe
if(-1 == pipe(fd)){
perror("pipe");
return -1;
}
// assign write_fd and read_fd
write_fd = fd[1];
read_fd = fd[0];
//parent pid
ppid = getpid();
//each child process to count the number of words in each file
pid = fork();
for (int i = 0; i < argc-1; i++)
{
//child process
if (pid == 0) {
close(read_fd);
child_process(write_fd, argv[i+1], ppid);
break;
} else {
pid = fork();
}
}
// don't let child run beyond this point
if (pid == 0) {
exit(0);
}
// parent only code
if (pid > 0)
{
close(write_fd);
while (read(read_fd, (void*)&recvd, 1) > 0)
{
wait(NULL);
totalwords += recvd;
}
close(read_fd);
}
printf("Main process created %d child processes to count words in %d files\n", argc - 1, argc - 1);
printf("Total words is %d\n", totalwords);
printf("%d files have been counted sucessfully!\n", argc - 1);
}