UTIMES(2) | NetBSD System Calls Manual | UTIMES(2)

# NAME

utimes, lutimes, futimes, futimens, utimensat — set file access and modification times

# LIBRARY

Standard C Library (libc, -lc)

# 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 fd, const struct timeval times[2]);

int
futimens(int fd, const struct timespec times[2]);

int
utimensat(int fd, const char *path, const struct timespec times[2], int flag);

# DESCRIPTION

The access and modification times of the file named by path or referenced by fd are changed as specified by the argument times.

If times is NULL, the access and modification times are set to the current time. The caller must be the owner of the file, have permission to write the file, or be the super-user.

If times is non-NULL, it is assumed to point to an array of two timeval structures. The access time is set to the value of the first element, and the modification time is set to the value of the second element. For file systems that support file birth (creation) times (such as UFS2), the birth time will be set to the value of the second element if the second element is older than the currently set birth time. To set both a birth time and a modification time, two calls are required; the first to set the birth time and the second to set the (presumably newer) modification time. Ideally a new system call will be added that allows the setting of all three times at once. The caller must be the owner of the file or be the super-user.

In either case, the inode-change-time of the file is set to the current time.

lutimes() is like utimes() except in the case where the named file is a symbolic link, in which case lutimes() changes the access and modification times of the link, while utimes() changes the times of the file the link references.

futimens() is like futimes() except that time is specified with nanosecond instead of microseconds.

utimensat() also allows time to be specifed with nanoseconds. When it operates on a symbolic link, it will change the target's time if follow is unset. If follow is set to AT_SYMLINK_NOFOLLOW, the symbolic link's dates are changed.

The nanosecond fields for futimens() and utimensat() can be set to the special value UTIME_NOW to set the current time, or to UTIME_OMIT to let the time unchanged (this allows changing access time but not modification time, and vice-versa).

utimensat() is partially implemented. It will return ENOSYS for fd values different than AT_FDCWD.

# RETURN VALUES

Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.

# ERRORS

utimes(), lutimes(), and utimensat() will fail if:

[EACCES]
  Search permission is denied for a component of the path prefix; or the times argument is NULL and the effective user ID of the process does not match the owner of the file, and is not the super-user, and write access is denied.
[EFAULT]
  path or times points outside the process's allocated address space.
[EIO]
  An I/O error occurred while reading or writing the affected inode.
[ELOOP]
  Too many symbolic links were encountered in translating the pathname.
[ENAMETOOLONG]
  A component of a pathname exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} characters.
[ENOENT]
  The named file does not exist.
[ENOTDIR]
  A component of the path prefix is not a directory.
[EPERM]
  The times argument is not NULL and the calling process's effective user ID does not match the owner of the file and is not the super-user.
[EROFS]
  The file system containing the file is mounted read-only.

futimes() and futimens() will fail if:

[EACCES]
  The times argument is NULL and the effective user ID of the process does not match the owner of the file, and is not the super-user, and write access is denied.
[EBADF]
  fd does not refer to a valid descriptor.
[EFAULT]
  times points outside the process's allocated address space.
[EIO]
  An I/O error occurred while reading or writing the affected inode.
[EPERM]
  The times argument is not NULL and the calling process's effective user ID does not match the owner of the file and is not the super-user.
[EROFS]
  The file system containing the file is mounted read-only.

# SEE ALSO

stat(2), utime(3), symlink(7)

# STANDARDS

The utimes() function conforms to IEEE Std 1003.1-2001 (“POSIX.1”). It was however marked as legacy in the IEEE Std 1003.1-2004 (“POSIX.1”) revision. futimens() and utmensat() functions conform to IEEE Std 1003.1-2008 (“POSIX.1”).

# HISTORY

The utimes() function call appeared in 4.2BSD. The futimes() function call appeared in NetBSD 1.2. The lutimes() function call appeared in NetBSD 1.3. Birthtime setting support was added in NetBSD 5.0. futimens() and utimensat() functions calls appreared in NetBSD 6.0.

# BUGS

utimensat() is partially implemented.

August 17, 2011 | NetBSD 5.99