Tribblix: manual page: utimes.2

UTIMES(2) System Calls UTIMES(2)

NAME

utimes, lutimes, futimes, futimesat, futimens, 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(7). 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}.