utime.3p (5433B)
- '\" et
- .TH UTIME "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH PROLOG
- 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.
- .\"
- .SH NAME
- utime
- \(em set file access and modification times
- .SH SYNOPSIS
- .LP
- .nf
- #include <utime.h>
- .P
- int utime(const char *\fIpath\fP, const struct utimbuf *\fItimes\fP);
- .fi
- .SH DESCRIPTION
- The
- \fIutime\fR()
- function shall set the access and modification times of the file named
- by the
- .IR path
- argument.
- .P
- If
- .IR 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
- \fIutime\fR()
- in this manner.
- .P
- If
- .IR times
- is not a null pointer,
- .IR times
- shall be interpreted as a pointer to a
- .BR 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
- \fIutime\fR()
- this way.
- .P
- The
- .BR utimbuf
- structure is defined in the
- .IR <utime.h>
- header. The times in the structure
- .BR utimbuf
- are measured in seconds since the Epoch.
- .P
- Upon successful completion, the
- \fIutime\fR()
- function shall mark the last file status change timestamp
- for update; see
- .IR <sys/stat.h> .
- .SH "RETURN VALUE"
- Upon successful completion, 0 shall be returned. Otherwise, \-1
- shall be returned and
- .IR errno
- shall be set to indicate the error, and the file times shall not be
- affected.
- .SH ERRORS
- The
- \fIutime\fR()
- function shall fail if:
- .TP
- .BR EACCES
- Search permission is denied by a component of the path prefix; or the
- .IR 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.
- .TP
- .BR ELOOP
- A loop exists in symbolic links encountered during resolution of the
- .IR path
- argument.
- .TP
- .BR ENAMETOOLONG
- .br
- The length of a component of a pathname is longer than
- {NAME_MAX}.
- .TP
- .BR ENOENT
- A component of
- .IR path
- does not name an existing file or
- .IR path
- is an empty string.
- .TP
- .BR 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
- .IR path
- argument contains at least one non-\c
- <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.
- .TP
- .BR EPERM
- The
- .IR 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.
- .TP
- .BR EROFS
- The file system containing the file is read-only.
- .br
- .P
- The
- \fIutime\fR()
- function may fail if:
- .TP
- .BR ELOOP
- More than
- {SYMLOOP_MAX}
- symbolic links were encountered during resolution of the
- .IR path
- argument.
- .TP
- .BR ENAMETOOLONG
- .br
- 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}.
- .LP
- .IR "The following sections are informative."
- .SH EXAMPLES
- None.
- .SH "APPLICATION USAGE"
- Since the
- .BR utimbuf
- structure only contains
- .BR time_t
- variables and is not accurate to fractions of a second,
- applications should use the
- \fIutimensat\fR()
- function instead of the obsolescent
- \fIutime\fR()
- function.
- .SH RATIONALE
- The
- .IR 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
- \fIstat\fR()
- or
- \fIfstat\fR()
- to retrieve the file's
- .IR st_atim
- and
- .IR st_mtim
- parameters, set
- .IR actime
- and
- .IR modtime
- in the buffer, and change one of them before making the
- \fIutime\fR()
- call.
- .SH "FUTURE DIRECTIONS"
- The
- \fIutime\fR()
- function may be removed in a future version.
- .SH "SEE ALSO"
- .IR "\fIfstat\fR\^(\|)",
- .IR "\fIfstatat\fR\^(\|)",
- .IR "\fIfutimens\fR\^(\|)"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "\fB<sys_stat.h>\fP",
- .IR "\fB<utime.h>\fP"
- .\"
- .SH 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 .
- .PP
- 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 .