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1#include??/*?根據(jù)POSIX.1?-?2001?*/
2/*根據(jù)早期的標(biāo)準(zhǔn)*/
3#include
4#include
5#include

 1int?select(int?nfds,?fd_set?*readset,?fd_set?*writeset,
 2???????????fd_set?*exceptset,?struct?timeval?*timeout);
 3
 4參數(shù)解析:
 5nfds?:??????需要檢查的文件描述符個(gè)數(shù)，數(shù)值應(yīng)該比是三組fd_set中最大數(shù)更大，而不是實(shí)際文件描述符的總數(shù)。
 6readset:????用來(lái)檢查可讀性的一組文件描述符。
 7writeset:???用來(lái)檢查可寫性的一組文件描述符。
 8exceptset:??用來(lái)檢查意外狀態(tài)的文件描述符。(注：錯(cuò)誤并不是意外狀態(tài))
 9timeout:????NULL指針代表無(wú)限等待，否則是指向timeval結(jié)構(gòu)的指針，代表最長(zhǎng)等待時(shí)間。(如果其中tv_sec和?
10????????????tv_usec都等于0,?則文件描述符的狀態(tài)不被影響，但函數(shù)并不掛起)

1fd_set?set;
2FD_ZERO(&set);???????/*?將set清零?*/
3FD_SET(fd,?&set);????/*?將fd加入set?*/
4FD_CLR(fd,?&set);????/*?將fd從set中清除?*/
5FD_ISSET(fd,?&set);??/*?如果fd在set中則真　*/

 1int?isready(int?fd)
 2{
 3?????????int?rc;
 4?????????fd_set?fds;
 5?????????struct?timeval?tv;
 6
 7?????????FD_ZERO(&fds);
 8?????????FD_SET(fd,&fds);
 9?????????tv.tv_sec?=?tv.tv_usec?=?0;
10
11?????????rc?=?select(fd+1,?&fds,?NULL,?NULL,?&tv);
12?????????if?(rc?0)
13???????????return?-1;
14
15?????????return?FD_ISSET(fd,&fds)???1?:?0;
16}

1#include?
2int?poll(struct?pollfd?fds[],?nfds_t?nfds,?int?timeout)；

1struct?pollfd?
2{
3????int?fd;????????/*?文件描述符?*/
4????short?events;??/*?等待的事件?*/
5????short?revents;?/*?實(shí)際發(fā)生了的事件?*/
6};

1fds[0].events?=?POLLIN;?/*將測(cè)試條件設(shè)置成普通或優(yōu)先級(jí)帶數(shù)據(jù)可讀*/

1//這樣就可以監(jiān)聽(tīng)fds里面文件描述符了，當(dāng)滿足特定條件就返回，并將結(jié)果保存在revents中。
2int?pollresult?=?poll(fds,xx,xx);?

 1#include?
 2#include?
 3#include?
 4#include?
 5#include?
 6#include?
 7#include?
 8#include?
 9
10#define?MAX_BUFFER_SIZE?1024
11#define?IN_FILES?3
12#define?TIME_DELAY?60*5
13#define?MAX(a,b)?((a>b)?(a):(b))
14
15int?main(int?argc?,char?**argv)
16{
17??struct?pollfd?fds[IN_FILES];
18??char?buf[MAX_BUFFER_SIZE];
19??int?i,res,real_read,?maxfd;
20??fds[0].fd?=?0;
21??if((fds[1].fd=open("data1",O_RDONLY|O_NONBLOCK))?0)
22????{
23??????fprintf(stderr,"open?data1?error:%s",strerror(errno));
24??????return?1;
25????}
26??if((fds[2].fd=open("data2",O_RDONLY|O_NONBLOCK))?0)
27????{
28??????fprintf(stderr,"open?data2?error:%s",strerror(errno));
29??????return?1;
30????}
31??for?(i?=?0;?i?32????{
33??????fds[i].events?=?POLLIN;
34????}
35??while(fds[0].events?||?fds[1].events?||?fds[2].events)
36????{
37??????if?(poll(fds,?IN_FILES,?TIME_DELAY)?<=?0)
38????{
39?????printf("Poll?error\n");
40?????return?1;
41????}
42??????for?(i?=?0;?i43????{
44?????if?(fds[i].revents)
45???????{
46?????????memset(buf,?0,?MAX_BUFFER_SIZE);
47?????????real_read?=?read(fds[i].fd,?buf,?MAX_BUFFER_SIZE);
48?????????if?(real_read?0)
49????????{
50?????????if?(errno?!=?EAGAIN)
51???????????{
52?????????????return?1;
53???????????}
54????????}
55?????????else?if?(!real_read)
56????????{
57?????????close(fds[i].fd);
58?????????fds[i].events?=?0;
59????????}
60?????????else
61????????{
62?????????if?(i?==?0)
63???????????{
64?????????????if?((buf[0]?==?'q')?||?(buf[0]?==?'Q'))
65????????????{
66?????????????return?1;
67????????????}
68???????????}
69?????????else
70???????????{
71?????????????buf[real_read]?=?'\0';
72?????????????printf("%s",?buf);
73???????????}
74????????}
75???????}
76????}
77????}
78??exit(0);
79}