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

NAME

     utime, utimes - change file last access and modification times

SYNOPSIS

     #include <sys/types.h>
     #include <utime.h>

     int utime(const char *filename, const struct utimbuf *times);

     #include <sys/time.h>

     int utimes(const char *filename, const struct timeval times[2]);

DESCRIPTION

     Note: modern applications may prefer to use the interfaces described in
     utimensat(2).

     The utime() system call changes the access and  modification  times  of
     the  inode  specified  by  filename to the actime and modtime fields of
     times respectively.

     If times is NULL, then the access and modification times  of  the  file
     are set to the current time.

     Changing timestamps is permitted when: either the process has appropri-
     ate privileges, or the effective user ID equals  the  user  ID  of  the
     file,  or  times  is  NULL and the process has write permission for the
     file.

     The utimbuf structure is:

         struct utimbuf {
             time_t actime;       /* access time */
             time_t modtime;      /* modification time */ };

     The utime() system call allows specification of timestamps with a reso-
     lution of 1 second.

     The  utimes()  system call is similar, but the times argument refers to
     an array rather than a structure.   The  elements  of  this  array  are
     timeval structures, which allow a precision of 1 microsecond for speci-
     fying timestamps.  The timeval structure is:

         struct timeval {
             long tv_sec;        /* seconds */
             long tv_usec;       /* microseconds */ };

     times[0] specifies the new access time, and times[1] specifies the  new
     modification  time.  If times is NULL, then analogously to utime(), the
     access and modification times of the file are set to the current  time.

RETURN VALUE

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

ERRORS

     EACCES Search permission is denied for one of the  directories  in  the
            path prefix of path (see also path_resolution(7)).

     EACCES times is NULL, the caller's effective user ID does not match the
            owner of the file, the caller does not have write access to  the
            file,  and  the  caller  is not privileged (Linux: does not have
            either the CAP_DAC_OVERRIDE or the CAP_FOWNER capability).

     ENOENT filename does not exist.

     EPERM  times is not NULL, the caller's effective UID does not match the
            owner of the file, and the caller is not privileged (Linux: does
            not have the CAP_FOWNER capability).

     EROFS  path resides on a read-only filesystem.

CONFORMING TO

     utime(): SVr4, POSIX.1-2001.  POSIX.1-2008 marks utime() as obsolete.

     utimes(): 4.3BSD, POSIX.1-2001.

NOTES

     Linux does not allow changing the timestamps on an immutable  file,  or
     setting  the  timestamps to something other than the current time on an
     append-only file.