STAT(2)                                                                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
       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.

       Lstat  is  like  stat except in the case where the named file is a sym‐
       bolic link, in which case lstat returns  information  about  the  link,
       while stat returns information about the file the link references.

       Fstat obtains the same information about an open file referenced by the
       argument descriptor, such as would be obtained by an open call.

       Buf is a pointer to a stat structure into which information  is  placed
       concerning the file.  The contents of the structure pointed to by buf

            struct stat {
                 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 */
                 int    st_spare1;
                 time_t st_mtime;/* file last modify time */
                 int    st_spare2;
                 time_t st_ctime;/* file last status change time */
                 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),  read(2),
                   and  write(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 i-node.   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 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)).

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.

ERRORS
       Stat and lstat will fail if one or more of the following are true:

       [ENOTDIR]      A component of the path prefix is not a directory.

       [EINVAL]       The pathname contains a character  with  the  high-order
                      bit set.

       [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an
                      entire path name exceeded 1023 characters.

       [ENOENT]       The named file does not exist.

       [EACCES]       Search permission is denied for a component of the  path
                      prefix.

       [ELOOP]        Too  many symbolic links were encountered in translating
                      the pathname.

       [EFAULT]       Buf or name points to an invalid address.

       [EIO]          An I/O error occurred while reading from or  writing  to
                      the file system.

       Fstat will fail if one or both of the following are true:

       [EBADF]        Fildes is not a valid open file descriptor.

       [EFAULT]       Buf points to an invalid address.

       [EIO]          An  I/O  error occurred while reading from or writing to
                      the file system.

CAVEAT
       The fields in the stat structure currently marked st_spare1, st_spare2,
       and  st_spare3 are present in preparation for inode time stamps expand‐
       ing to 64 bits.  This, however, can break certain programs that  depend
       on the time stamps being contiguous (in calls to utimes(2)).

SEE ALSO
       chmod(2), chown(2), utimes(2)

BUGS
       Applying  fstat  to  a  socket  (and  thus  to a pipe) returns a zero’d
       buffer, except for the blocksize field, and a unique device  and  inode
       number.


4th Berkeley Distribution        May 12, 1986                          STAT(2)
 
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