updwtmp(3) — Linux manual page

updwtmp(3)              Library Functions Manual              updwtmp(3)

NAME         top

       updwtmp, logwtmp - append an entry to the wtmp file

LIBRARY         top

       System utilities library (libutil, -lutil)

SYNOPSIS         top

       #include <utmp.h>

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

DESCRIPTION         top

       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         top

       /var/log/wtmp
              database of past user logins

ATTRIBUTES         top

       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()          │               │                          │
       └────────────────────┴───────────────┴──────────────────────────┘

VERSIONS         top

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

           #define _GNU_SOURCE          /* See feature_test_macros(7) */
           #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.

STANDARDS         top

       None.

HISTORY         top

       Solaris, NetBSD.

SEE ALSO         top

       getutxent(3), wtmp(5)

COLOPHON         top

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Linux man-pages 6.9.1          2024-05-02                     updwtmp(3)

Pages that refer to this page: utmp(5)

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