posix-queue-epoll-server

posix-queue-epoll-server.c

#include <stdio.h>
#include <mqueue.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h> //for close
#include <sys/epoll.h> // for epoll_create1(), epoll_ctl(), struct epoll_event

#define PATH_URI "/corermanipc"

#define MAX_LEN 2000

#define MAX_EVENTS 5

#define TIME_OUT 30000

int main() {

    char *info = (char *) malloc(sizeof(char) * MAX_LEN);

    int recvlen = 0;

    mqd_t mqd = mq_open(PATH_URI, O_CREAT | O_RDWR | O_NONBLOCK, 0x660, NULL);

    if (mqd == -1) {

        printf("MQ open faild : %s\n", strerror(errno));

    } else {

        int epoll_fd = epoll_create1(0);
        if (epoll_fd == -1) {

            printf("epoll create faild : %s\n", strerror(errno));

        } else {

            struct epoll_event event, events[MAX_EVENTS];

            event.events = EPOLLIN;

            event.data.fd = mqd;

            if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, mqd, &event)) {

                printf("epoll ctl faild : %s\n", strerror(errno));

                close(epoll_fd);

            }

            int event_count, i;

            struct mq_attr mqatt;

            mq_getattr(mqd, &mqatt);

            while (1) {

                event_count = epoll_wait(epoll_fd, events, MAX_EVENTS, TIME_OUT);

                for (i = 0; i < event_count; i++) {

                    if (events[i].data.fd == mqd) {

                        recvlen = mq_receive(mqd, info, mqatt.mq_msgsize, NULL);

                        if (recvlen != -1) {

                            printf("%s\n", info);

                        } else {

                            printf("epoll recv faild : %s\n", strerror(errno));

                        }

                    }

                }

            }

        }

    }

    free(info);

    mq_close(mqd);

    return 0;
}