将poll程序改为epoll实现
原实例在APUE（第三版）17.2 UNIX域套接字
1、使用UNIX与套接字轮询XSI消息队列（poll版，原版）
| 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 71 72 73 74 75 76 77 78 79 80 81 82 83 84 | #include "apue.h" #include 【将poll程序改为epoll实现】 #include #include #include #define NQ3//队列的数量 #define MAXMSZ512//消息的最大长度 #define KEY0x123//消息队列的第一个key值 struct
threadinfo { int
qid;
int
fd;
};
struct
mymesg { long
mtype;
char
mtext[MAXMSZ];
};
void
*helper(
void
*arg) { int
n;
struct
mymesg m;
struct
threadinfo *tip = arg;
for
(;
;
) { printf
(
"helper qid %d, fd %d, tid %u\n"
, tip->qid, tip->fd, (unsigned)pthread_self());
memset
(&m, 0,
sizeof
(m));
if
((n = msgrcv(tip->qid, &m, MAXMSZ, 0, MSG_NOERROR)) < 0) { err_sys(
"msgrcv error"
);
} if
(write(tip->fd, m.mtext, n) < 0) { err_sys(
"write error"
);
} } } int
main() { int
i, n, err;
int
fd[2];
int
qid[NQ];
struct
pollfd pfd[NQ];
struct
threadinfo ti[NQ];
pthread_t tid[NQ];
char
buf[MAXMSZ];
for
(i = 0;
i < NQ;
++i) { if
((qid[i] = msgget((KEY+i), IPC_CREAT|0666)) < 0) {
//创建一个新队列 err_sys(
"msgget error"
);
} printf
(
"queue %d ID is %d\n"
, i, qid[i]);
if
(socketpair(AF_UNIX, SOCK_DGRAM, 0, fd) < 0) {
//创建UNXI域套接字（fd管道） err_sys(
"socketpair error"
);
} printf
(
"fd[0]:%d\n"
, fd[0]);
printf
(
"fd[1]:%d\n"
, fd[1]);
pfd[i].fd = fd[0];
pfd[i].events = POLLIN;
ti[i].qid = qid[i];
ti[i].fd = fd[1];
if
((err = pthread_create(&tid[i], NULL, helper, &ti[i])) != 0) {
//创建线程 err_exit(err,
"pthread_create error"
);
} } for
(;
;
) { if
(poll(pfd, NQ, -1) < 0) {
//等待事件发生 err_sys(
"poll error"
);
} for
(i = 0;
i < NQ;
++i) { //printf("i:%d\n", i);
if
(pfd[i].revents & POLLIN) { if
((n = read(pfd[i].fd, buf,
sizeof
(buf))) < 0) { err_sys(
"read error"
);
} buf[n] = 0;
printf
(
"queue %d id %d, message %s\n"
, i, qid[i], buf);
} } } exit
(0);
} |
| 1 | gcc pollmsg.c -o pollmsg -lapue -lpthread -std=c99 |
| 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 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 | #include "apue.h" #include #include #include #include #define NQ3//队列的数量 #define MAXMSZ512//消息的最大长度 #define KEY0x123//消息队列的第一个key值 #define FDSIZE1000 #define EPOLLEVENTS100 struct
threadinfo { int
qid;
int
fd;
};
struct
mymesg { long
mtype;
char
mtext[MAXMSZ];
};
void
*helper(
void
*arg) { int
n;
struct
mymesg m;
struct
threadinfo *tip = arg;
for
(;
;
) { printf
(
"helper qid %d, fd %d, tid %u\n"
, tip->qid, tip->fd, (unsigned)pthread_self());
memset
(&m, 0,
sizeof
(m));
if
((n = msgrcv(tip->qid, &m, MAXMSZ, 0, MSG_NOERROR)) < 0) { err_sys(
"msgrcv error"
);
} if
(write(tip->fd, m.mtext, n) < 0) { err_sys(
"write error"
);
} } } int
main() { int
i, n, err;
int
fd[2];
int
qid[NQ];
int
epollfd;
struct
epoll_event events[EPOLLEVENTS];
struct
threadinfo ti[NQ];
pthread_t tid[NQ];
char
buf[MAXMSZ];
epollfd = epoll_create(FDSIZE);
//创建epoll文件描述符 for
(i = 0;
i < NQ;
++i) { if
((qid[i] = msgget((KEY+i), IPC_CREAT|0666)) < 0) {
//创建一个新队列 err_sys(
"msgget error"
);
} printf
(
"queue %d ID is %d\n"
, i, qid[i]);
if
(socketpair(AF_UNIX, SOCK_DGRAM, 0, fd) < 0) {
//创建UNXI域套接字（fd管道） err_sys(
"socketpair error"
);
} struct
epoll_event ev;
ev.events = EPOLLIN;
ev.data.fd = fd[0];
epoll_ctl(epollfd, EPOLL_CTL_ADD, fd[0], &ev);
//注册fd[0]到epoll ti[i].qid = qid[i];
ti[i].fd = fd[1];
if
((err = pthread_create(&tid[i], NULL, helper, &ti[i])) != 0) {
//创建线程 err_exit(err,
"pthread_create error"
);
} } for
(;
;
) { int
occurred;
if
((occurred = epoll_wait(epollfd, events, EPOLLEVENTS, -1)) < 0) {
//等待事件发生 err_sys(
"epoll error"
);
} if
(occurred == 0) { err_sys(
"epoll timeout"
);
} for
(i = 0;
i < occurred;
++i) { if
(events[i].events & EPOLLIN) { if
((n = read(events[i].data.fd, buf,
sizeof
(buf))) < 0) { err_sys(
"read error"
);
} buf[n] = 0;
printf
(
"main thread %u, message %s\n"
, (unsigned)pthread_self(), buf);
} } } exit
(0);
} |
| 1 | gcc epollmsg.c -o epollmsg -lapue -lpthread -std=c99 |
| 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 | #include "apue.h" #include #define MAXMSZ 512 struct
mymesg { long
mtype;
char
mtext[MAXMSZ];
};
int
main(
int
argc,
char
*argv[]) { key_t key;
long
qid;
size_t
nbytes;
struct
mymesg m;
if
(argc != 3) { fprintf
(stderr,
"usage: sendmsg KEY message\n"
);
exit
(1);
} key =
strtol
(argv[1], NULL, 0);
//printf("key:0x%08X\n", (unsigned )key);
if
((qid = msgget(key, 0)) < 0) {
//打开一个现有队列 err_sys(
"can't open queue key %s"
, argv[1]);
} memset
(&m, 0,
sizeof
(m));
strncpy
(m.mtext, argv[2], MAXMSZ - 1);
nbytes =
strlen
(m.mtext);
m.mtype = 1;
//printf("qid:%ld\n", qid);
if
(msgsnd(qid, &m, nbytes, 0) < 0) {
//发送消息给指定消息队列 err_sys(
"can't send message"
);
} exit
(0);
} |
| 1 | gcc sendmsg.c -o sendmsg -lapue -std=c99 |
相关阅读：
1、select、poll、epoll之间的区别总结[整理]
2、poll函数的使用，原文
3、APUE读书笔记
*** walker ***
本文转自walker snapshot博客51CTO博客，原文链接http://blog.51cto.com/walkerqt/1768445如需转载请自行联系原作者
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