-
Notifications
You must be signed in to change notification settings - Fork 0
/
pipe-3.cpp
54 lines (49 loc) · 875 Bytes
/
pipe-3.cpp
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
#include <iostream>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
using namespace std;
int main(int argc, char *argv[]) {
char *cmd1 = argv[1];
char *cmd2 = argv[2];
char *cmd3 = argv[3];
char *filename = argv[4];
int fds[2];
pipe(fds);
if (!fork()) {
dup2(fds[1], 1);
close(fds[0]);
close(fds[1]);
if (!fork()) {
execlp(cmd1, cmd1, NULL);
exit(1);
}
wait(NULL);
if (!fork()) {
execlp(cmd2, cmd2, NULL);
exit(1);
}
wait(NULL);
exit(0);
}
if (!fork()) {
// child 3
int fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
dup2(fd, 1);
close(fd);
dup2(fds[0], 0);
close(fds[0]);
close(fds[1]);
execlp(cmd3, cmd3, NULL);
exit(1);
}
close(fds[0]);
close(fds[1]);
wait(NULL);
wait(NULL);
return 0;
}