多路转接之poll和select

先看poll()：

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <sys/stat.h>
 5 #include <sys/types.h>
 6 #include <fcntl.h>
 7 #include <poll.h>
 8 
 9 #define oops(x, n) { perror(x); exit(n); }
10 
11 int main()
12 {
13     mkfifo("fifo1", 0644);    
14     mkfifo("fifo2", 0644);    
15     
16     int fd1 = open("fifo1", O_RDWR);
17     int fd2 = open("fifo2", O_RDWR);
18     char buf[1000];
19     for(;;)
20     {
21         struct pollfd pfd[] = {{0, POLLIN}, {fd1, POLLIN}, {fd2, POLLIN}};
22         int ret = poll(pfd, 3, 1);
23         if(ret > 0)
24         {
25             if(pfd[0].revents&POLLIN)
26             {
27                 scanf(" %[^
]", buf);    
28                 printf("keypad:%s
", buf);
29                 if(strcmp(buf, "quit") == 0) break;    
30             }
31             if(pfd[1].revents&POLLIN)
32             {
33                 int n = read(fd1, buf, sizeof(buf));    
34                 buf[n] = '';
35                 printf("fifo1:%s", buf);
36             }
37             if(pfd[2].revents&POLLIN)
38             {
39                 int n = read(fd2, buf, sizeof(buf));    
40                 buf[n] = '';
41                 printf("fifo2:%s", buf);
42             }
43         }
44 
45     }
46     close(fd1);
47     close(fd2);
48     unlink("fifo1");
49     unlink("fifo2");
50 
51     return 0;
52 }

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再来说说select()：

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <sys/stat.h>
 5 #include <sys/types.h>
 6 #include <fcntl.h>
 7 #include <poll.h>
 8 
 9 #define oops(x, n) { perror(x); exit(n); }
10 
11 int main()
12 {
13     mkfifo("fifo1", 0644);    
14     mkfifo("fifo2", 0644);    
15     
16     int fd1 = open("fifo1", O_RDWR);
17     int fd2 = open("fifo2", O_RDWR);
18     char buf[1000];
19     for(;;)
20     {
21         struct pollfd pfd[] = {{0, POLLIN}, {fd1, POLLIN}, {fd2, POLLIN}};
22         int ret = poll(pfd, 3, 1);
23         if(ret > 0)
24         {
25             if(pfd[0].revents&POLLIN)
26             {
27                 scanf(" %[^
]", buf);    
28                 printf("keypad:%s
", buf);
29                 if(strcmp(buf, "quit") == 0) break;    
30             }
31             if(pfd[1].revents&POLLIN)
32             {
33                 int n = read(fd1, buf, sizeof(buf));    
34                 buf[n] = '';
35                 printf("fifo1:%s", buf);
36             }
37             if(pfd[2].revents&POLLIN)
38             {
39                 int n = read(fd2, buf, sizeof(buf));    
40                 buf[n] = '';
41                 printf("fifo2:%s", buf);
42             }
43         }
44 
45     }
46     close(fd1);
47     close(fd2);
48     unlink("fifo1");
49     unlink("fifo2");
50 
51     return 0;
52 }

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