NAME
utimes, lutimes, futimes, futimesat - 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);
int
lutimes(const char *path, const struct timeval *times);
int
futimes(int fd, const struct timeval *times);
int
futimesat(int fd, const char *path, const struct timeval times[2]);
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.
The lutimes() system call 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.
The futimesat() system call is equivalent to utimes() except in the case
where path specifies a relative path. In this case the access and
modification time is set to that of a file relative to the directory
associated with the file descriptor fd instead of the current working
directory. If futimesat() is passed the special value AT_FDCWD in the fd
parameter, the current working directory is used and the behavior is
identical to a call to utimes().
RETURN VALUES
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable errno is set to indicate the
error.
ERRORS
The utimes() and lutimes() system calls 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] The path or times argument 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.
[EPERM] The named file has its immutable or append-only flag
set, see the chflags(2) manual page for more
information.
[EROFS] The file system containing the file is mounted read-
only.
The futimes() system call will fail if:
[EBADF] The fd argument does not refer to a valid descriptor.
All of the system calls 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.
[EFAULT] The times argument points outside the process’s
allocated address space.
[EINVAL] The tv_usec component of at least one of the values
specified by the times argument has a value less than
0 or greater than 999999.
[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.
In addition to the errors returned by the utimes(), the futimesat() may
fail if:
[EBADF] The path argument does not specify an absolute path
and the fd argument is neither AT_FDCWD nor a valid
file descriptor open for searching.
[ENOTDIR] The path argument is not an absolute path and fd is
neither AT_FDCWD nor a file descriptor associated with
a directory.
SEE ALSO
chflags(2), stat(2), utime(3)
STANDARDS
The utimes() function is expected to conform to X/Open Portability Guide
Issue 4.2 (“XPG4.2”). The futimesat() system call follows The Open Group
Extended API Set 2 specification.
HISTORY
The utimes() system call appeared in 4.2BSD. The futimes() and lutimes()
system calls first appeared in FreeBSD 3.0. The futimesat() system call
appeared in FreeBSD 8.0.