#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <string.h>

int main()
{
        int pipefd[2];
        pid_t pid;
        if(pipe(pipefd) == -1)
        {
                perror("pipe() error!\n");
        }

        pid = fork();
        if(pid == -1)
        {
                perror("fork error()!\n");
                close(pipefd[0]);
                close(pipefd[1]);
                exit(-1);
        }
        else if(pid == 0)
        {
                close(pipefd[1]);

                char buffer[100];
                while(1)
                {
                        memset(buffer, 0, sizeof(buffer));
                        read(pipefd[0], buffer, sizeof(buffer));

                        if(strcmp(buffer, "quit") == 0)
                                break;

                        printf("child process: %s\n", buffer);
                }

                close(pipefd[0]);
        }
        else
        {
                close(pipefd[0]);

                char str[100];
                while(1)
                {
                        memset(str, 0, sizeof(str));
                        printf("input> ");
                        fgets(str, sizeof(str), stdin);
                        str[strlen(str)-1] = '\0';
#ifdef DEBUG
                        printf("[DEBUG] fgets: %s\n", str);
#endif
                        write(pipefd[1], str, strlen(str));
                        if(strcmp(str, "quit") == 0)
                        {
                                wait(NULL);
                                break;
                        }

                }

                close(pipefd[1]);
        }

        return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70