UTIME(3)                   POSIX Programmer's Manual                  UTIME(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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 .



IEEE/The Open Group                  2017                             UTIME(3)
