'\" t
.\" Copyright 1997 Nicolás Lichtmaier <nick@debian.org>
.\" Created Wed Jul  2 23:27:34 ART 1997
.\"
.\" SPDX-License-Identifier: GPL-2.0-or-later
.\"
.\" Added info on availability, aeb, 971207
.\" Added -lutil remark, 030718
.\" 2008-07-02, mtk, document updwtmpx()
.\"
.TH updwtmp 3 2023-10-31 "Linux man-pages 6.7"
.SH NAME
updwtmp, logwtmp \- append an entry to the wtmp file
.SH LIBRARY
System utilities library
.RI ( libutil ", " \-lutil )
.SH SYNOPSIS
.nf
.B #include <utmp.h>
.P
.BI "void updwtmp(const char *" wtmp_file ", const struct utmp *" ut );
.BI "void logwtmp(const char *" line ", const char *" name \
", const char *" host );
.fi
.SH DESCRIPTION
.BR updwtmp ()
appends the utmp structure
.I ut
to the wtmp file.
.P
.BR logwtmp ()
constructs a utmp structure using
.IR line ", " name ", " host ,
current time, and current process ID.
Then it calls
.BR updwtmp ()
to append the structure to the wtmp file.
.SH FILES
.TP
.I /var/log/wtmp
database of past user logins
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR updwtmp (),
.BR logwtmp ()
T}	Thread safety	MT-Unsafe sig:ALRM timer
.TE
.SH VERSIONS
For consistency with the other "utmpx" functions (see
.BR getutxent (3)),
glibc provides (since glibc 2.1):
.P
.in +4n
.EX
.BR "#define _GNU_SOURCE          " "/* See feature_test_macros(7) */"
.B #include <utmpx.h>
.BI "void updwtmpx (const char *" wtmpx_file ", const struct utmpx *" utx );
.EE
.in
.P
This function performs the same task as
.BR updwtmp (),
but differs in that it takes a
.I utmpx
structure as its last argument.
.SH STANDARDS
None.
.SH HISTORY
Solaris, NetBSD.
.SH SEE ALSO
.BR getutxent (3),
.BR wtmp (5)