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, 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 .