STAT(2) COMMAND REFERENCE STAT(2)
NAME
stat, lstat, fstat - get file status
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
stat(path, buf)
char *path;
struct stat *buf;
lstat(path, buf)
char *path;
struct stat *buf;
fstat(fd, buf)
int fd;
struct stat *buf;
DESCRIPTION
The command stat obtains information about the file path.
Read, write or execute permission of the named file is not
required, but all directories listed in the path name
leading to the file must be reachable.
The lstat command is like stat except in the case where the
named file is a symbolic link, in which case lstat returns
information about the link, while stat returns information
about the file the link references.
The command fstat obtains the same information about an open
file referenced by fd, such as would be obtained by an open
call.
A pointer buf points to a stat structure into which
information is placed concerning the file; the structure is
defined in <sys/stat.h> as:
struct stat {
dev_t st_dev; /* ID of device containing a directory
/* entry for this file */
ino_t st_ino; /* this inode's number */
u_short st_mode; /* file mode; see below */
short st_nlink; /* number of hard links to the file */
short st_uid; /* user ID of the file's owner */
short st_gid; /* group ID of the file's group */
dev_t st_rdev; /* ID of device -- this entry is
/* defined only */
/* for character special or block
/* special files */
off_t st_size; /* total size of file */
time_t st_atime; /* time of last access */
Printed 5/12/88 1
STAT(2) COMMAND REFERENCE STAT(2)
int st_spare1;
time_t st_mtime; /* time of last data modification */
int st_spare2;
time_t st_ctime; /* time of last file status change */
int st_spare3;
long st_blksize; /* optimal blocksize for file system
/* I/O ops */
long st_blocks; /* actual number of blocks allocated */
long st_spare4[2];
};
st_atime
Time when file data was last read or modified.
Changed by the following system calls: mknod(2),
utimes(2), and read(2). For reasons of efficiency,
st_atime is not set when a directory is searched,
although this would be more logical.
st_mtime
Time when data was last modified; it is not set by
changes of owner, group, link count, or mode.
Changed by the following system calls: mknod(2),
utimes(2), write(2).
st_ctime
Time when file status was last changed; it is set
both both by writing and changing the inode.
Changed by the following system calls: chmod(2),
chown(2), link(2), mknod(2), rename(2), unlink(2),
utimes(2), write(2).
The status information word st_mode has these bits:
#define S_IFMT 0170000 /* type of file */
#define S_IFDIR 0040000 /* directory */
#define S_IFCHR 0020000 /* character special */
#define S_IFBLK 0060000 /* block special */
#define S_IFREG 0100000 /* regular */
#define S_IFLNK 0120000 /* symbolic link */
#define S_IFSOCK 0140000 /* socket */
#define S_ISUID 0004000 /* set user id on execution */
#define S_ISGID 0002000 /* set group id on execution */
#define S_ISVTX 0001000 /* save swapped text even after use */
#define S_IREAD 0000400 /* read permission, owner */
#define S_IWRITE 0000200 /* write permission, owner */
#define S_IEXEC 0000100 /* execute/search permission, owner */
The mode bits 0000070 and 0000007 encode group and others
permissions (see chmod(2)).
Printed 5/12/88 2
STAT(2) COMMAND REFERENCE STAT(2)
When fd is associated with a pipe, fstat reports an ordinary
file with an inode number, restricted permissions, and a not
necessarily meaningful length.
DIAGNOSTICS
The commands stat and lstat fail if one or more of the
following are true:
[ENOTDIR] A component of the path prefix is not a
directory.
[ENOASCII] The path name contains a character with the
high-order bit set.
[ENAMETOOLONG] The path name is too long.
[ENOENT] The named file does not exist.
[EFAULT] Buf or path points to an invalid address.
[ELOOP] Too many symbolic links were encountered in
translating the path name.
[EIO] An I/O error occurred while reading from or
writing to the file system.
The fstat command fails if one of the following are true:
[EBADF] Fd is not a valid open file descriptor.
[EIO] An I/O error occurred while reading from or
writing to the file system.
RETURN VALUE
Upon successful completion a value of 0 is returned.
Otherwise, a value of -1 is returned and errno is set to
indicate the error.
CAVEATS
The fields in the stat structure currently marked st_spare1,
st_spare2, and st_spare3 are present in preparation for
inode time stamps expanding to 64 bits. This, however, can
break certain programs which depend on the time stamps being
contiguous (in calls to utimes(2)).
Applying fstat to a socket returns a zeroed buffer.
SEE ALSO
chmod(2), chown(2), and utimes(2).
Printed 5/12/88 3
%%index%%
na:240,88;
sy:328,1867;
de:2195,2070;4577,2390;7279,223;
di:7502,1189;
rv:8691,279;
ca:8970,540;
se:9510,160;
%%index%%000000000143