#include <stdio.h>  
#include <stdlib.h>   
  
#include <sys/types.h>  
#include <sys/stat.h>  
#include <fcntl.h>  
  
#define TEMP_PATH "/sys/class/thermal/thermal_zone0/temp"  
#define MAX_SIZE 32  
int main(void)   
{  
        int fd; 
        double temp = 0;  
        char buf[MAX_SIZE];  
        // 打开/sys/class/thermal/thermal_zone0/temp  
        fd = open(TEMP_PATH, O_RDONLY);  
        if (fd < 0) {  
            fprintf(stderr, "failed to open thermal_zone0/temp\n");  
            return -1;  
        }
        // 读取内容  
        if (read(fd, buf, MAX_SIZE) < 0) {  
            fprintf(stderr, "failed to read temp\n");  
            return -1;  
        }  
                                  
        // 转换为浮点数打印  
        temp = atoi(buf) / 1000.0;  
        printf("temp: %.2f\n", temp);       
        // 关闭文件  
        close(fd);  
}