NAME

       updwtmp, logwtmp - append an entry to the wtmp file

SYNOPSIS

       #include <utmp.h>

       void updwtmp(const char *wtmp_file, const struct utmp *ut);
       void logwtmp(const char *line, const char *name, const char *host);

       For logwtmp(), link with -lutil.

DESCRIPTION

       updwtmp() appends the utmp structure ut to the wtmp file.

       logwtmp()  constructs  a  utmp  structure using line, name, host, current time and current
       process ID.  Then it calls updwtmp() to append the structure to the wtmp file.

FILES

       /var/log/wtmp
              database of past user logins

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌───────────┬───────────────┬──────────────────────────┐
       │Interface  │ Attribute     │ Value                    │
       ├───────────┼───────────────┼──────────────────────────┤
       │updwtmp(), │ Thread safety │ MT-Unsafe sig:ALRM timer │
       │logwtmp()  │               │                          │
       └───────────┴───────────────┴──────────────────────────┘

CONFORMING TO

       Not in POSIX.1.  Present on Solaris, NetBSD, and perhaps other systems.

NOTES

       For consistency with the other "utmpx" functions (see getutxent(3)), glibc provides (since
       version 2.1):

           #include <utmpx.h>
           void updwtmpx (const char *wtmpx_file, const struct utmpx *utx);

       This  function  performs  the same task as updwtmp(), but differs in that it takes a utmpx
       structure as its last argument.

SEE ALSO

       getutxent(3), wtmp(5)

COLOPHON

       This page is part of release 5.05 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at https://www.kernel.org/doc/man-pages/.