UTIME
Section: POSIX Programmer's Manual (3P)
Updated: 2017
Page Index
PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
utime
--- set file access and modification times
SYNOPSIS
#include <utime.h>
int utime(const char *path, const struct utimbuf *times);
DESCRIPTION
The
utime()
function shall set the access and modification times of the file named
by the
path
argument.
If
times
is a null pointer, the access and modification times of the file shall
be set to the current time. The effective user ID of the process shall
match the owner of the file, or the process has write permission to the
file or has appropriate privileges, to use
utime()
in this manner.
If
times
is not a null pointer,
times
shall be interpreted as a pointer to a
utimbuf
structure and the access and modification times shall be set to the
values contained in the designated structure. Only a process with
the effective user ID equal to the user ID of the file or a process with
appropriate privileges may use
utime()
this way.
The
utimbuf
structure is defined in the
<utime.h>
header. The times in the structure
utimbuf
are measured in seconds since the Epoch.
Upon successful completion, the
utime()
function shall mark the last file status change timestamp
for update; see
<sys/stat.h>.
RETURN VALUE
Upon successful completion, 0 shall be returned. Otherwise, -1
shall be returned and
errno
shall be set to indicate the error, and the file times shall not be
affected.
ERRORS
The
utime()
function shall 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, the process does not have write
permission for the file, and the process does not have appropriate
privileges.
- ELOOP
-
A loop exists in symbolic links encountered during resolution of the
path
argument.
- ENAMETOOLONG
-
The length of a component of a pathname is longer than
{NAME_MAX}.
- ENOENT
-
A component of
path
does not name an existing file or
path
is an empty string.
- ENOTDIR
-
A component of the path prefix names an existing file that is neither
a directory nor a symbolic link to a directory, or the
path
argument contains at least one non-<slash>
character and ends with one or more trailing
<slash>
characters and the last pathname component names an existing file
that is neither a directory nor a symbolic link to a directory.
- EPERM
-
The
times
argument is not a null pointer and the effective user ID of the calling
process does not match the owner of the file and the calling process
does not have appropriate privileges.
- EROFS
-
The file system containing the file is read-only.
The
utime()
function may fail if:
- ELOOP
-
More than
{SYMLOOP_MAX}
symbolic links were encountered during resolution of the
path
argument.
- ENAMETOOLONG
-
The length of a pathname exceeds
{PATH_MAX},
or pathname resolution of a symbolic link produced an intermediate
result with a length that exceeds
{PATH_MAX}.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
Since the
utimbuf
structure only contains
time_t
variables and is not accurate to fractions of a second,
applications should use the
utimensat()
function instead of the obsolescent
utime()
function.
RATIONALE
The
actime
structure member must be present so that an application may set it,
even though an implementation may ignore it and not change the last data
access timestamp on the file. If an application intends to leave one of
the times of a file unchanged while changing the other, it should use
stat()
or
fstat()
to retrieve the file's
st_atim
and
st_mtim
parameters, set
actime
and
modtime
in the buffer, and change one of them before making the
utime()
call.
FUTURE DIRECTIONS
The
utime()
function may be removed in a future version.
SEE ALSO
fstat(),
fstatat(),
futimens()
The Base Definitions volume of POSIX.1-2017,
<sys_stat.h>,
<utime.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .