-1
child_filter必须从pipefd中读取值并将其写入命名管道中。 问题是，如果我尝试取消注释注释[3]（命名管道的打开），函数将不会打印值，它似乎卡在read（）调用上。相反，如果我不打开fifo管道，它的工作原理。 我需要命名管道为其他东西。 我应该修改什么？也许管道和命名管道冲突一起使用它们？ 谢谢。在C中使用管道的命名管道块子进程
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <fcntl.h>
#define FIFONAME "./my-fgrep-named-pipe"
typedef struct{
int i;
int v;
int word;
int filename;
char word_string[250];
char filename_string[250];
}parameters;
int pipefd[2];
void child_reader(parameters params){
FILE* fp;
char *line = NULL;
size_t len = 0;
ssize_t read;
if(params.filename==0)
fp = stdin;
else
fp = fopen(params.filename_string, "r");
close(pipefd[0]); /* Close unused read end */
if (fp != NULL){
while ((read = getline(&line, &len, fp)) != -1) {
//printf("Retrieved line of length %zu :\n", read);
//printf("%s", line);
write(pipefd[1], line, strlen(line));
}
fclose(fp);
}
free(line);
printf("child reader > end\n");
exit(0);
}
void child_filter(parameters params){
char c;
char temp[250];
int i=0;
char *temp2;
int fifofd;
close(pipefd[1]); /* Close unused write pipe end */
printf("read from pipe\n");
if((fifofd = open(FIFONAME, O_WRONLY)) == -1) printf("Error WW\n");
while (read(pipefd[0], &c, 1) > 0){
if (c == '\n' || c == '\r'){
temp[i] = '\n';
if(i>0){
temp2=strtok(temp, "\n");
//temp2[i] = '\n';
// printf("[%s]\n", temp2);
write(fifofd, temp2, strlen(temp2));
}i=0;
}
else{
temp[i] = c;
i++;
}
}
close(fifofd);
printf("child filter > end\n");
exit(0);
}
void child_writer(parameters params){
char c;
int fifofd;
char temp[250];
int i=0;
char *temp2;
if((fifofd = open(FIFONAME, O_RDONLY)) == -1) printf("Error RR\n");
while (read(fifofd, &c, 1) > 0){
printf("entry > [%c] \n", c);
}
printf("exit-------------\n");
close(fifofd);
unlink(FIFONAME);
exit(0);
}
int main(int argc, char *argv[]){
char* temp1;
parameters params;
int forkResult;
params.i=0;
params.v=0;
params.word=0;
params.filename=0;
int pid_r, pid_w, pid_f;
if(argc<2){
printf("error\n");
exit(0);
}
if(strcmp(argv[1],"-i") == 0)
params.i++;
if(strcmp(argv[1],"-v") == 0)
params.v++;
if(argc>2){
if(strcmp(argv[2],"-i") == 0)
params.i++;
if(strcmp(argv[2],"-v") == 0)
params.v++;
}
if(params.i == 0 && params.v == 0){
params.word++;
strcpy(params.word_string, argv[1]);
if(argc>2){
params.filename++;
strcpy(params.filename_string, argv[2]);
}
}
else if(params.i != 0 && params.v != 0){
if(argc>3){
params.word++;
strcpy(params.word_string, argv[3]);
}
if(argc>4){
params.filename++;
strcpy(params.filename_string, argv[4]);
}
}
else{
if(argc>2){
params.word++;
strcpy(params.word_string, argv[2]);
}
if(argc>3){
params.filename++;
strcpy(params.filename_string, argv[3]);
}
}
printf("Result: i[%d], v[%d], name[%d], filename[%d]\n", params.i, params.v, params.word, params.filename);
if(params.word==0){
printf("Error X\n");
exit(0);
}
if (pipe(pipefd) == -1) {
printf("pipe error\n");
exit(0);
}
unlink(FIFONAME);
if(mkfifo(FIFONAME, 0666) != 0) printf("Error fifo1\n");
if((pid_r=fork()) == 0){
child_reader(params);
}
if((pid_f=fork()) == 0){
child_filter(params);
}
if((pid_w=fork()) == 0){
child_writer(params);
}
waitpid(pid_r, NULL, 0);
printf("Reader finished\n");
close(pipefd[1]);
waitpid(pid_f, NULL, 0);
close(pipefd[0]);
printf("filter finished\n");
waitpid(pid_w, NULL, 0);
printf("Done!\n");
exit(0);
}
您*设置'pipefd'的地方？你能否请尝试创建一个[最小，完整和可验证示例]（http://stackoverflow.com/help/mcve）并向我们展示？包括你如何初始化'pipefd'并调用这个函数？ –
也不是说，如果成功，'open'调用将返回'0'是不太可能的。请尝试检查“-1”。 –