留個備份，執行這個搭建程式可以在當前目錄生成ttyNeo1和ttyNeo2兩個互連的虛擬串列埠，在Linux上寫上位機和下位機串列埠通訊程式時就不需要利用物理串列埠測試了。

#define _XOPEN_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#include <poll.h> static int alive = 0;
static char buf[8*1024] = {0}; static void neo_handler(int sig)
{
    printf("got signal(%d)\n", sig);
    alive = 0;
} int main(int argc, char **argv)
{
    int ret = 0;
    int m1 = 0;
    int m2 = 0;
    char *pts = NULL;
    struct pollfd pollfds[2];     signal(SIGTERM, neo_handler);
    signal(SIGINT, neo_handler);     m1 = open("/dev/ptmx", O_RDWR);
    if (m1 < 0) {
        printf("open /dev/ptmx failed, errno=%d(%s)\n", errno, strerror(errno));
        return -1;
    }
    grantpt(m1);
    unlockpt(m1);     m2 = open("/dev/ptmx", O_RDWR);
    if (m2 < 0) {
        printf("open /dev/ptmx failed, errno=%d(%s)\n", errno, strerror(errno));
        goto err_m2;
    }
    grantpt(m2);
    unlockpt(m2);     pts = ptsname(m1);
    if (!pts)
        goto err_pts;
    remove("./ttyNeo1");
    ret = symlink(pts, "./ttyNeo1");
    if (ret < 0) {
        printf("create ./ttyNeo1 failed, errno=%d(%s)\n", errno, strerror(errno));
        goto err_pts;
    }
    pts = ptsname(m2);
    remove("./ttyNeo2");
    ret = symlink(pts, "./ttyNeo2");
    if (ret < 0) {
        printf("create ./ttyNeo2 failed, errno=%d(%s)\n", errno, strerror(errno));
        goto err_pts;
    }     memset(&pollfds, 0, sizeof(pollfds));
    pollfds[0].fd = m1;
    pollfds[0].events = POLLIN;
    pollfds[1].fd = m2;
    pollfds[1].events = POLLIN;
    alive = 1;
    while (alive) {
        ret = poll(&pollfds[0], 2, 500);
        if ((ret < 0) && (errno == EINTR) || (ret == 0))
            continue;
        else if (ret < 0) {
            printf("poll failed, errno=%d(%s)\n", errno, strerror(errno));
            break;
        }
        if (pollfds[0].revents & POLLIN) {
            memset(buf, 0, sizeof(buf));
            ret = read(m1, buf, sizeof(buf));
            if (ret > 0)
                write(m2, buf, ret);
            pollfds[0].revents = 0;
        }
        if (pollfds[1].revents & POLLIN) {
            memset(buf, 0, sizeof(buf));
            ret = read(m2, buf, sizeof(buf));
            if (ret > 0)
                write(m1, buf, ret);
            pollfds[1].revents = 0;
        }
    } err_pts:
    close(m2);
    m2 = -1;
err_m2:
    close(m1);
    m1 = -1;
    return 0;
}