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, utime() shall mark the time of the
last file status change, st_ctime, to be updated;
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 the path argument exceeds {PATH_MAX} or a pathname
component 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 is not a directory.
EPERM
The times argument is not a null pointer and the calling process'
effective user ID 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 utime() function may fail if:
ELOOP
More than {SYMLOOP_MAX} symbolic links were encountered during resolution
of the path argument.
ENAMETOOLONG
As a result of encountering a symbolic link in resolution of the path
argument, the length of the substituted pathname
string exceeded {PATH_MAX}.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
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 access time 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() to retrieve the file's
st_atime and
st_mtime parameters, set actime and modtime in the
buffer, and change one of them before making the
utime() call.
FUTURE DIRECTIONS
None.
SEE ALSO
The Base Definitions volume of IEEE Std 1003.1-2001, <sys/stat.h>,
<utime.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .
