linux下开发问题汇总

linux下网络编程学习

http://blog.csdn.net/Simba888888/article/category/1426325

select()使用例子

#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#define TIMEOUT 5
#define BUF_LEN 1024

int main(void)
{
        struct timeval tv;
        fd_set rfds;
        int ret;

        FD_ZERO(&rfds);
        FD_SET(STDIN_FILENO, &rfds);

        tv.tv_sec = TIMEOUT;
        tv.tv_usec = 0;

        ret = select(STDIN_FILENO+1, &rfds, NULL, NULL, &tv);
        if (ret == -1) {
                perror("select()");
                return 1;
        } else if (!ret) {
                printf("%d seconds elapsed.\n", TIMEOUT);
                return 0;
        }
        if (FD_ISSET(STDIN_FILENO, &rfds)) {
                char buf[BUF_LEN+1];
                int len;
                len = read(STDIN_FILENO, buf, BUF_LEN);
                if (len == -1) {
                        perror("read()");
                        return 1;
                }
                if (len) {
                        buf[len] = 0;
                        printf("read: %s\n", buf);
                }

                return 0;
        }

        fprintf(stderr, "This should not happen.\n");
        return 1;
}

 poll()使用例子

#include <stdio.h>
#include <unistd.h>
#include <poll.h>

#define TIMEOUT 5

int main(void)
{
        struct pollfd fds[2];
        int ret;

        fds[0].fd = STDIN_FILENO;
        fds[0].events = POLLIN;

        fds[1].fd = STDOUT_FILENO;
        fds[1].events = POLLOUT;

        ret = poll(fds, 2, TIMEOUT*1000);
        if (ret == -1) {
                perror("poll()");
                return 1;
        }
        if (!ret) {
                printf("%d seconds elapsed.\n", TIMEOUT);
                return 0;
        }
        if (fds[0].revents & POLLIN)
                printf("stdin is readable\n");
        if (fds[1].revents & POLLOUT)
                printf("stdout is writable\n");

        return 0;
}