LDD-LinuxDeviceDrivers/study/kernel/02-memory/00-code/mmap/test.c

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

#define PAGE_SIZE 4096


int main(int argc , char *argv[])
{

    int fd;
    int i;
    unsigned char *p_map;


    //打开设备
    fd = open("/dev/mymap",O_RDWR);

    if(fd < 0)
    {
        printf("open fail\n");
        exit(1);
    }



    //内存映射
    p_map = (unsigned char *)mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, 0);
    if(p_map == MAP_FAILED)
    {

        printf("mmap fail\n");
        goto here;
    }



    //打印映射后的内存中的前10个字节内容
    for(i=0;i<10;i++)
    {
        printf("%d\n",p_map[i]);
        p_map[i] = i + 10;
    }




here:

    munmap(p_map, PAGE_SIZE);
    return 0;
}