OpenBSD可加载内核模块编程完全指南

OpenBSD可加载内核模块编程完全指南(12)         (dev_type_stop((*))) lkmenodev, 0, (dev_type_select((*))) lkmenodev,
        (dev_type_mmap((*))) lkmenodev }

#endif /* _KERNEL */

Now this is the program we'll use to test (chardevtest.c):
#include <sys/types.h>
#include <sys/ioctl.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <err.h>

#include "common.h"

int
main(void)
{
        struct ourdev_io a;
        int error, fd;

        fd = open("/dev/ourdev", O_WRONLY);
        if (fd == -1)
                err(1, "open");

        error = ioctl(fd, ODREAD, &a);
        if (error == -1)
                err(1, "ioctl");

        printf("%d %s", a.value, a.msg);
        
        bzero(a.msg, MAXMSGLEN);

        strlcpy(a.msg, "cowsn", sizeof(a.msg));
        a.value = 42;

        error = ioctl(fd, ODWRITE, &a);
        if (error == -1)
                err(1, "ioctl");

        bzero(&a, sizeof(struct ourdev_io));