UTIMES(2) System Calls UTIMES(2)


NAME


utimes, lutimes, futimes, futimesat, utimens, utimensat - set file access
and modification times

SYNOPSIS


#include <sys/time.h>

int utimes(const char *path, const struct timeval times[2]);


int lutimes(const char *path, const struct timeval times[2]);


int futimes(int fildes, const struct timeval times[2]);


int futimesat(int fildes, const char *path,
const struct timeval times[2]);


#include <sys/stat.h>

int futimens(int fildes, const timespec_t nstimes[2]);

int utimensat(int fildes, const char *path,
const timespec_t nstimes[2], int flag);


DESCRIPTION


The utimes() function sets the access and modification times of the file
pointed to by the path argument to the value of the times argument. It
allows time specifications accurate to the microsecond.


The lutimes() function operates like utimes() except if path points to a
symbolic link; in that case lutimes() changes the access and
modifications times of the link, while utimes() changes the file that is
referenced by the link.


The futimes() function sets the access and modification times of the file
referenced by the file descriptor fildes.


The futimesat() function also sets access and modification times. See
fsattr(5). If path is a relative path name, however, futimesat() resolves
the path relative to the fildes argument rather than the current working
directory. If fildes is set to AT_FDCWD, defined in <fcntl.h>,
futimesat() resolves the path relative to the current working directory.
If path is a null pointer, futimesat() sets the access and modification
times on the file referenced by fildes. The fildes argument is ignored if
futimesat() is provided with an absolute path.


The times argument is an array of timeval structures. The first array
member represents the date and time of last access, and the second member
represents the date and time of last modification. The times in the
timeval structure are measured in seconds and microseconds since the
Epoch, although rounding toward the nearest second may occur.


If the times argument is a null pointer, the access and modification
times of the file are set to the current time. The effective user ID of
the process must be the same as the owner of the file, or must have write
access to the file or the {PRIV_FILE_OWNER} privilege to use this call in
this manner. Upon completion, utimes() will mark the time of the last
file status change, st_ctime, for update.


The futimens() and utimensat() functions also set access and modification
times; however, instead of taking struct timeval, they take timespec_t
which allows for nanosecond granularity. The futimens() function sets the
access and modification times on the file descriptor referenced by
fildes.


The utimensat() function determines the file to set the access and
modification times in an similar way to futimesat(). If the argument path
is an absolute path, then the argument fildes is ignored; otherwise, path
is interpreted as a path relative to the directory specified by fildes.
If fildes is set to AT_FDCWD, then path is resolved relative to the
current working directory. The behavior when encountering symbolic links
may be controlled by the value of the flag argument. If the value of flag
is the constant AT_SYMLINK_NOFOLLOW, then when a symbolic link is
encountered while resolving a path, it will not be followed. Otherwise,
the value of flag should be 0. Note that, unlike futimesat(), utimensat()
does not accept a null pointer for the path argument.

RETURN VALUES


Upon successful completion, 0 is returned. Otherwise, -1 is returned,
errno is set to indicate the error, and the file times will not be
affected.

ERRORS


The utimes(), lutimes(), futimes(), futimesat(), futimens(), and
utimensat() functions will fail if:

EACCES
Search permission is denied by a component of the path
prefix; or the times argument is a null pointer and the
effective user ID of the process does not match the owner
of the file and write access is denied.


EFAULT
The path or times argument points to an illegal address.


EINTR
A signal was caught during the execution of the utimes(),
lutimes(), futimes(), futimesat(), futimens(), or
utimensat() functions.


EINVAL
The number of microseconds specified in one or both of
the timeval structures pointed to by times was greater
than or equal to 1,000,000 or less than 0. The number of
nanoseconds specified in one or both of the timespec_t
structures pointed to by nstimes was greater than or
equal to 1,000,000,000 or less than 0.


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


ELOOP
Too many symbolic links were encountered in resolving
path.


ENAMETOOLONG
The length of the path argument exceeds {PATH_MAX} or a
pathname component is longer than {NAME_MAX}.


ENOLINK
The path argument points to a remote machine and the link
to that machine is no longer active.


ENOENT
A component of path does not name an existing file or
path is an empty string.


ENOTDIR
A component of the path prefix is not a directory or the
path argument is relative and the fildes argument is not
AT_FDCWD or does not refer to a valid directory.


EPERM
The times argument is not a null pointer and the calling
process's effective user ID has write access to the file
but does not match the owner of the file and the calling
process does not have the appropriate privileges.


EROFS
The file system containing the file is read-only.


The utimes(), futimesat(), and utimensat() functions may fail if:

ENAMETOOLONG
Path name resolution of a symbolic link produced an
intermediate result whose length exceeds {PATH_MAX}.


ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Committed |
+--------------------+-----------------+
|Standard | See below. |
+--------------------+-----------------+


For utimes(), utimensat() and futimensat(), see standards(5).

SEE ALSO


fBstat(2), utime(2), attributes(5), fsattr(5), standards(5)


September 6, 2020 UTIMES(2)