C lstat major MAJOR 获得设备号

#cat lstat.c

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include <stdio.h>

#include <string.h>

#define MINORBITS   20

#define MINORMASK   ((1U << MINORBITS) - 1)

#define MAJOR(dev)  ((unsigned int) ((dev) >> MINORBITS))

#define MINOR(dev)  ((unsigned int) ((dev) & MINORMASK))

int main(void)

{

	struct stat buf;

	lstat("/dev/sdc", &buf);

	int a = MAJOR(buf.st_dev);

	int b = MINOR(buf.st_dev);

	int c = MAJOR(buf.st_rdev);

	int d = MINOR(buf.st_rdev);

	int e = major(buf.st_rdev);

	int f = minor(buf.st_rdev);

	int g = major(buf.st_dev);

	int h = minor(buf.st_dev);

	printf("st_dev MAJOR:%d, MINOR:%d\n", a, b);

	printf("st_rdev MAJOR:%d, MINOR:%d\n", c, d);

	printf("st_dev major:%d, minor:%d\n", g, h);

	printf("st_rdev major:%d, minor:%d\n", e, f);

	return 0;

}

#./lstat

st_dev MAJOR:0, MINOR:5

st_rdev MAJOR:0, MINOR:2080

st_dev major:0, minor:5

st_rdev major:8, minor:32