1UTIME(2)                   Linux Programmer's Manual                  UTIME(2)
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NAME

6       utime, utimes - change file last access and modification times
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SYNOPSIS

9       #include <sys/types.h>
10       #include <utime.h>
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12       int utime(const char *filename, const struct utimbuf *times);
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14       #include <sys/time.h>
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16       int utimes(const char *filename, const struct timeval times[2]);
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DESCRIPTION

19       The  utime()  system  call changes the access and modification times of
20       the inode specified by filename to the actime  and  modtime  fields  of
21       times respectively.
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23       If  times  is  NULL, then the access and modification times of the file
24       are set to the current time.
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26       Changing timestamps is permitted when: either the process has appropri‐
27       ate  privileges,  or  the  effective  user ID equals the user ID of the
28       file, or times is NULL and the process has  write  permission  for  the
29       file.
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31       The utimbuf structure is:
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33           struct utimbuf {
34               time_t actime;       /* access time */
35               time_t modtime;      /* modification time */
36           };
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38       The utime() system call allows specification of timestamps with a reso‐
39       lution of 1 second.
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41       The utimes() system call is similar, but the times argument  refers  to
42       an  array  rather  than  a  structure.   The elements of this array are
43       timeval structures, which allow a precision of 1 microsecond for speci‐
44       fying timestamps.  The timeval structure is:
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46           struct timeval {
47               long tv_sec;        /* seconds */
48               long tv_usec;       /* microseconds */
49           };
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51       times[0]  specifies the new access time, and times[1] specifies the new
52       modification time.  If times is NULL, then analogously to utime(),  the
53       access and modification times of the file are set to the current time.
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RETURN VALUE

56       On  success,  zero is returned.  On error, -1 is returned, and errno is
57       set appropriately.
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ERRORS

60       EACCES Search permission is denied for one of the  directories  in  the
61              path prefix of path (see also path_resolution(7)).
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63       EACCES times is NULL, the caller's effective user ID does not match the
64              owner of the file, the caller does not have write access to  the
65              file,  and  the  caller  is not privileged (Linux: does not have
66              either the CAP_DAC_OVERRIDE or the CAP_FOWNER capability).
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68       ENOENT filename does not exist.
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70       EPERM  times is not NULL, the caller's effective UID does not match the
71              owner of the file, and the caller is not privileged (Linux: does
72              not have the CAP_FOWNER capability).
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74       EROFS  path resides on a read-only file system.
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CONFORMING TO

77       utime(): SVr4, POSIX.1-2001.  POSIX.1-2008 marks utime() as obsolete.
78       utimes(): 4.3BSD, POSIX.1-2001.
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NOTES

81       Linux does not allow changing the timestamps on an immutable  file,  or
82       setting  the  timestamps to something other than the current time on an
83       append-only file.
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85       In libc4 and libc5, utimes() is just a wrapper for  utime()  and  hence
86       does not allow a subsecond resolution.
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SEE ALSO

89       chattr(1), futimesat(2), stat(2), utimensat(2), futimes(3), futimens(3)
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COLOPHON

92       This  page  is  part of release 3.22 of the Linux man-pages project.  A
93       description of the project, and information about reporting  bugs,  can
94       be found at http://www.kernel.org/doc/man-pages/.
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98Linux                             2008-08-06                          UTIME(2)
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