utimes(2) - NetBSD Manual Pages

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


NAME

     utimes, lutimes, futimes, futimens, utimensat -- set file access and mod-
     ification 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 cur-
     rent 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 modifica-
     tion 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 nanosec-
     ond 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 val-
     ues 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 translat-
                        ing the pathname.

     [ENAMETOOLONG]     A component of a pathname exceeded {NAME_MAX} charac-
                        ters, or an entire path name exceeded {PATH_MAX} char-
                        acters.

     [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 utimensat() 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.

NetBSD 6.0                      August 17, 2011                     NetBSD 6.0