糖尿病康复 > stat lstat fstat及stat结构体

stat lstat fstat及stat结构体

时间：2019-03-07 05:57:01

struct stat {dev_tst_dev;/* ID of device containing file */--文件所在设备IDino_tst_ino;/* inode number */--节点号mode_t st_mode; /* protection */--文件类型nlink_t st_nlink; /* number of hard links */--硬链接个数uid_tst_uid;/* user ID of owner */--所有者IDgid_tst_gid;/* group ID of owner */--组IDdev_tst_rdev; /* device ID (if special file) */--特殊文件IDblksize_t st_blksize; /* blocksize for file system I/O */--系统文件i/o的块大小off_tst_size; /* total size, in bytes */--大小，单位字节blkcnt_t st_blocks; /* number of 512B blocks allocated */--分配的512b块数time_t st_atime; /* time of last access */--上次访问time_t st_mtime; /* time of last modification */--最近一次修改time_t st_ctime; /* time of last status change */--最近一次的状态变化};

st_dev：描述该文件所在的设备，由两部分组成（主设备号major(3)，从设备号minor(3)）

主设备号：标识设备类；

从设备号：标识特定实例

int major(dev_t dev);int minor(dev_t dev);

st_ino：节点号，是唯一标识文件的，如果你发现有两个文件节点号一样，那是硬连接哦！st_mode：为了更好地确定文件的类型，定义了以下的宏（macros）

The following POSIX macros are defined to check the file type using the st_mode field:S_ISREG(m) is it a regular file? //它是普通文件？S_ISDIR(m) directory?//目录？S_ISCHR(m) character device?//字符设备？S_ISBLK(m) block device?//块设备？S_ISFIFO(m) FIFO (named pipe)?//管道？S_ISLNK(m) symbolic link? (Not in POSIX.1-1996.)//符号链接？(不在 POSIX.1-1996。)S_ISSOCK(m) socket? (Not in POSIX.1-1996.) //套接口？(不在 POSIX.1-1996。)

下面标志为 st_mode 域定义：

st_nlink:硬链接个数st_rdev:特殊文件IDst_size:size of the filest_blocks:分配给文件的块数, 512 字节单位st_blksize:gives the “preferred” blocksize for efficient file system I/O,对系统而言最优的块大小。对于三种时间自己列了一张表，方便对比学习

stat lstat fstat应用实例

这里提一点，man文档上不是每个都有实例的。只有那些重要，不容易弄懂的，才会写上实例供所有人参考。有很重要的参考价值！！！

实例二—man手册

#include <sys/types.h>#include <sys/stat.h>#include <time.h>//时间的头文件#include <stdio.h>#include <stdlib.h>//没有的话，exit要报警告#include <sys/sysmacros.h>/****************************************************************************************** get file status(获取文件状态)** stat():文件路径** int stat(const char *path, struct stat *buf);** fstat():文件句柄**int fstat(int fd, struct stat *buf);** lstat():文件路径**int lstat(const char *path, struct stat *buf);** RETURN VALUE** On success, zero is returned. On error, -1 is returned****************************************************************************************/int main(int argc, char *argv[]){struct stat sb;//定义一个结构体变量if (argc != 2) {fprintf(stderr, "Usage: %s <pathname>\n", argv[0]);//stderr--标准错误输出设备, stdout输出到磁盘文件，stderr在屏幕哦exit(EXIT_FAILURE);}if (lstat(argv[1], &sb) == -1) {//第一个参数：pathperror("lstat");exit(EXIT_FAILURE);}printf("ID of containing device: [%lx,%lx]\n",//主设备，从设备(long) major(sb.st_dev), (long) minor(sb.st_dev));printf("File type:");//文件类型switch (sb.st_mode & S_IFMT) {//S_IFMT:文件类型位域掩码,与case S_IFBLK: printf("block device\n"); break;case S_IFCHR: printf("character device\n"); break;case S_IFDIR: printf("directory\n");break;case S_IFIFO: printf("FIFO/pipe\n");break;case S_IFLNK: printf("symlink\n"); break;case S_IFREG: printf("regular file\n"); break;case S_IFSOCK: printf("socket\n"); break;default: printf("unknown?\n");break;}printf("I-node number: %ld\n", (long) sb.st_ino);//节点号printf("Mode: %lo (octal)\n",//八进制(向左靠齐)(unsigned long) sb.st_mode);printf("Link count:%ld\n", (long) sb.st_nlink);//链接个数printf("Ownership:UID=%ld GID=%ld\n",//UID,GID(long) sb.st_uid, (long) sb.st_gid);printf("Preferred I/O block size: %ld bytes\n",//gives the "preferred" blocksize for efficient file system I/O(long) sb.st_blksize);printf("File size:%lld bytes\n",//文件大小，单位字节(long long) sb.st_size);printf("Blocks allocated: %lld\n",//占用块数(long long) sb.st_blocks);printf("Last status change: %s", ctime(&sb.st_ctime));//三个时间，文件访问时更改printf("Last file access: %s", ctime(&sb.st_atime));//文件更改时更新printf("Last file modification: %s", ctime(&sb.st_mtime));exit(EXIT_SUCCESS);}

输出：很清晰了解所有参数的含义，这里提一点：文件大小与所占块数不是线性的。

实例二

#include <stdio.h>//stat头文件#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <fcntl.h>//open头文件//stat结构体//struct stat {//dev_tst_dev;/* ID of device containing file */--设备id//ino_tst_ino;/* inode number */--节点号//mode_t st_mode; /* protection */--权限//nlink_t st_nlink; /* number of hard links */--硬链接//uid_tst_uid;/* user ID of owner */--用户ID//gid_tst_gid;/* group ID of owner */--组ID//dev_tst_rdev; /* device ID (if special file) */--特殊文件ID//blksize_t st_blksize; /* blocksize for file system I/O */--系统文件i/o的块大小//off_tst_size; /* total size, in bytes */--大小，单位字节//blkcnt_t st_blocks; /* number of 512B blocks allocated */--分配的512b块数//time_t st_atime; /* time of last access */--上次访问//time_t st_mtime; /* time of last modification */--最近一次修改//time_t st_ctime; /* time of last status change */--最近一次的状态变化//};/****************************************************************************************** get file status(获取文件状态)** stat():文件路径** int stat(const char *path, struct stat *buf);** fstat():文件句柄**int fstat(int fd, struct stat *buf);** lstat():文件路径**int lstat(const char *path, struct stat *buf);** RETURN VALUE** On success, zero is returned. On error, -1 is returned****************************************************************************************/int main(int argc, char *argv[]){int fd, ret;struct stat groupstat;if(argc<2)//至少需要传入两个参数，第一个程序名字，第二个要查看文件状态的文件路径{printf("Please enter two arguments!!!\n");return 1;}//statret = stat(argv[1], &groupstat);//返回indo,jiif(ret){printf("List-stat groupstat error!!!\n");return 1;}printf("The st_ino of %s id %d.\n",argv[1], groupstat.st_ino);//fstatif((fd = open(argv[1],O_RDWR|O_NDELAY|O_NOCTTY))<0){printf("Open %s failed!!!\n",argv[1]);return 1;}ret = fstat(fd, &groupstat);if(ret){printf("List--fstat groupstat error!!!\n");return 1;}printf("The st_ino of %s id %d.\n",argv[1], groupstat.st_ino);//lstatret = lstat(argv[1], &groupstat);if(ret){printf("List--lstat groupstat error!!!\n");return 1;}printf("The st_ino of %s id %d.\n",argv[1], groupstat.st_ino);return 0;}

输出：三个函数输出一样，ok.

参考博客：

/wh_19910525/article/details/13503221

如果觉得《stat lstat fstat及stat结构体》对你有帮助，请点赞、收藏，并留下你的观点哦！

本内容不代表本网观点和政治立场，如有侵犯你的权益请联系我们处理。

网友评论

网友评论仅供其表达个人看法，并不表明网站立场。