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utimes, futimesat - set file access and modification times

#include <sys/time.h>

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

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

#include <sys/stat.h>

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

int utimensat(int filedes, 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 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 even when
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 filedes.

The utimensat() function determines the file to set the access and
modification times in an similar way to futemsat(). If the argument
path is an absolute path, then the argument filedes is ignored;
otherwise, path is interpreted as a path relative to the directory
specified by filedes. If filedes 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.
 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(), 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. For
futimesat(), path might have the value NULL if the
fildes argument refers to a valid open file descriptor.


EINTR

A signal was caught during the execution of the utimes(),
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

futimens(2), stat(2), utime(2), attributes(5),
fsattr(5), standards(5)