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 super-user privileges to use this call in this manner. Upon completion, utimes() will mark the time of the last file status change, st_ctime, for update.

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.

The utimes() and futimesat() 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() function.

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.

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() and futimesat() functions may fail if:

ENAMETOOLONG

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

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

stat(2), attributes(5), fsattr(5)