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28 .\" @(#)stat.2 8.4 (Berkeley) 5/1/95
45 .Fn stat "const char * restrict path" "struct stat * restrict sb"
47 .Fn lstat "const char * restrict path" "struct stat * restrict sb"
49 .Fn fstat "int fd" "struct stat *sb"
51 .Fn fstatat "int fd" "const char *path" "struct stat *sb" "int flag"
55 system call obtains information about the file pointed to by
57 Read, write or execute
58 permission of the named file is not required, but all directories
59 listed in the path name leading to the file must be searchable.
65 except in the case where the named file is a symbolic link,
68 returns information about the link,
71 returns information about the file the link references.
75 system call obtains the same information about an open file
76 known by the file descriptor
81 system call is equivalent to
85 except in the case where the
87 specifies a relative path.
88 In this case the status is retrieved from a file relative to
89 the directory associated with the file descriptor
91 instead of the current working directory.
95 are constructed by a bitwise-inclusive OR of flags from the following list,
98 .Bl -tag -width indent
99 .It Dv AT_SYMLINK_NOFOLLOW
102 names a symbolic link, the status of the symbolic link is returned.
107 is passed the special value
111 parameter, the current working directory is used and the behavior is
112 identical to a call to
116 respectively, depending on whether or not the
117 .Dv AT_SYMLINK_NOFOLLOW
123 argument is a pointer to a
128 and into which information is placed concerning the file.
132 related to the file system are as follows:
133 .Bl -tag -width ".Va st_nlink"
135 The numeric ID of the device containing the file.
137 The file's inode number.
139 The number of hard links to the file.
146 fields together identify the file uniquely within the system.
148 The time-related fields of
151 .Bl -tag -width ".Va st_birthtim"
153 Time when file data last accessed.
154 Changed implicitly by syscalls such as
161 Time when file data last modified.
162 Changed implicitly by syscalls such as
169 Also, any syscall which modifies directory content changes the
171 for the affected directory.
180 Time when file status was last changed (inode data modification).
181 Changed implicitly by any syscall that affects file metadata, including
191 Also, any syscall which modifies directory content changes the
193 for the affected directory.
202 Time when the inode was created.
205 The following time-related macros are defined for compatibility:
207 #define st_atime st_atim.tv_sec
208 #define st_mtime st_mtim.tv_sec
209 #define st_ctime st_ctim.tv_sec
210 #ifndef _POSIX_SOURCE
211 #define st_birthtime st_birthtim.tv_sec
214 #ifndef _POSIX_SOURCE
215 #define st_atimespec st_atim
216 #define st_mtimespec st_mtim
217 #define st_ctimespec st_ctim
218 #define st_birthtimespec st_birthtim
222 The size-related fields of the
225 .Bl -tag -width ".Va st_blksize"
227 The file size in bytes.
229 The optimal I/O block size for the file.
231 The actual number of blocks allocated for the file in 512-byte units.
232 As short symbolic links are stored in the inode, this number may
236 The access-related fields of
239 .Bl -tag -width ".Va st_mode"
241 The user ID of the file's owner.
243 The group ID of the file.
245 Status of the file (see below).
248 The status information word
250 has the following bits:
252 #define S_IFMT 0170000 /* type of file mask */
253 #define S_IFIFO 0010000 /* named pipe (fifo) */
254 #define S_IFCHR 0020000 /* character special */
255 #define S_IFDIR 0040000 /* directory */
256 #define S_IFBLK 0060000 /* block special */
257 #define S_IFREG 0100000 /* regular */
258 #define S_IFLNK 0120000 /* symbolic link */
259 #define S_IFSOCK 0140000 /* socket */
260 #define S_IFWHT 0160000 /* whiteout */
261 #define S_ISUID 0004000 /* set user id on execution */
262 #define S_ISGID 0002000 /* set group id on execution */
263 #define S_ISVTX 0001000 /* save swapped text even after use */
264 #define S_IRWXU 0000700 /* RWX mask for owner */
265 #define S_IRUSR 0000400 /* read permission, owner */
266 #define S_IWUSR 0000200 /* write permission, owner */
267 #define S_IXUSR 0000100 /* execute/search permission, owner */
268 #define S_IRWXG 0000070 /* RWX mask for group */
269 #define S_IRGRP 0000040 /* read permission, group */
270 #define S_IWGRP 0000020 /* write permission, group */
271 #define S_IXGRP 0000010 /* execute/search permission, group */
272 #define S_IRWXO 0000007 /* RWX mask for other */
273 #define S_IROTH 0000004 /* read permission, other */
274 #define S_IWOTH 0000002 /* write permission, other */
275 #define S_IXOTH 0000001 /* execute/search permission, other */
278 For a list of access modes, see
283 The following macros are available to test whether a
287 argument corresponds to a file of the specified type:
288 .Bl -tag -width ".Fn S_ISFIFO m"
290 Test for a block special file.
292 Test for a character special file.
294 Test for a directory.
296 Test for a pipe or FIFO special file.
298 Test for a symbolic link.
300 Test for a regular file.
307 The macros evaluate to a non-zero value if the test is true
308 or to the value 0 if the test is false.
312 Previous versions of the system used different types for the
327 system calls will fail if:
330 Search permission is denied for a component of the path prefix.
337 points to an invalid address.
339 An I/O error occurred while reading from or writing to the file system.
341 Too many symbolic links were encountered in translating the pathname.
342 .It Bq Er ENAMETOOLONG
343 A component of a pathname exceeded 255 characters,
344 or an entire path name exceeded 1023 characters.
346 The named file does not exist.
348 A component of the path prefix is not a directory.
350 The file size in bytes cannot be
351 represented correctly in the structure pointed to by
357 system call will fail if:
363 is not a valid open file descriptor.
368 points to an invalid address.
370 An I/O error occurred while reading from or writing to the file system.
372 The file size in bytes cannot be
373 represented correctly in the structure pointed to by
377 In addition to the errors returned by the
386 argument does not specify an absolute path and the
390 nor a valid file descriptor open for searching.
394 argument is not valid.
398 argument is not an absolute path and
402 nor a file descriptor associated with a directory.
418 system calls are expected to conform to
422 system call follows The Open Group Extended API Set 2 specification.
428 system calls appeared in
432 system call appeared in
436 system call appeared in
442 returns a zeroed buffer,
443 except for the blocksize field,
444 and a unique device and inode number.