Section: POSIX Programmer's Manual (3P)
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.
--- set file access and modification times
int utime(const char *path, const struct utimbuf *times);
function shall set the access and modification times of the file named
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
in this manner.
is not a null pointer,
shall be interpreted as a pointer to a
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
structure is defined in the
header. The times in the structure
are measured in seconds since the Epoch.
Upon successful completion, the
function shall mark the last file status change timestamp
for update; see
Upon successful completion, 0 shall be returned. Otherwise, -1
shall be returned and
shall be set to indicate the error, and the file times shall not be
function shall fail if:
Search permission is denied by a component of the path prefix; or the
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
A loop exists in symbolic links encountered during resolution of the
The length of a component of a pathname is longer than
A component of
does not name an existing file or
is an empty string.
A component of the path prefix names an existing file that is neither
a directory nor a symbolic link to a directory, or the
argument contains at least one non-<slash>
character and ends with one or more trailing
characters and the last pathname component names an existing file
that is neither a directory nor a symbolic link to a directory.
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.
The file system containing the file is read-only.
function may fail if:
symbolic links were encountered during resolution of the
The length of a pathname exceeds
or pathname resolution of a symbolic link produced an intermediate
result with a length that exceeds
The following sections are informative.
structure only contains
variables and is not accurate to fractions of a second,
applications should use the
function instead of the obsolescent
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
to retrieve the file's
in the buffer, and change one of them before making the
function may be removed in a future version.
The Base Definitions volume of POSIX.1-2008,
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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
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