.TH STAT 2 "27 July 1983"
stat, lstat, fstat \- get file status
obtains information about the file
permission of the named file is not required, but all directories
listed in the path name leading to the file must be reachable.
is like \fIstat\fP except in the case where the named file is a symbolic link,
returns information about the link,
returns information about the file the link references.
obtains the same information about an open file
referenced by the argument descriptor, such as would
be obtained by an \fIopen\fP call.
structure into which information is placed concerning the file.
The contents of the structure pointed to by
dev_t st_dev; /* device inode resides on */
ino_t st_ino; /* this inode's number */
u_short st_mode; /* protection */
short st_nlink; /* number or hard links to the file */
short st_uid; /* user-id of owner */
short st_gid; /* group-id of owner */
dev_t st_rdev; /* the device type, for inode that is device */
off_t st_size; /* total size of file */
time_t st_atime; /* file last access time */
time_t st_mtime; /* file last modify time */
time_t st_ctime; /* file last status change time */
long st_blksize; /* optimal blocksize for file system i/o ops */
long st_blocks; /* actual number of blocks allocated */
Time when file data was last read or modified. Changed by the following system
For reasons of efficiency,
st_atime is not set when a directory
is searched, although this would be more logical.
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:
Time when file status was last changed.
It is set both both by writing and changing the i-node.
Changed by the following system calls:
The status information word \fIst_mode\fP has 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
is associated with a pipe,
reports an ordinary file with an i-node number,
and a not necessarily meaningful length.
Upon successful completion a value of 0 is returned.
Otherwise, a value of \-1 is returned and
is set to indicate the error.
will fail if one or more of the following are true:
A component of the path prefix is not a directory.
The pathname contains a character with the high-order bit set.
The pathname was too long.
The named file does not exist.
Search permission is denied for a component of the path prefix.
points to an invalid address.
will fail if one or both of the following are true:
is not a valid open file descriptor.
points to an invalid address.
Too many symbolic links were encountered in translating the pathname.
The fields in the stat structure currently marked
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
chmod(2), chown(2), utimes(2)
to a socket returns a zero'd buffer.
The list of calls which modify the various fields should be carefully