UPDWTMP(3)                                                              Linux Programmer's Manual                                                             UPDWTMP(3)

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(), logwtmp()                                                                                                 │ Thread safety │ MT-Unsafe sig:ALRM timer │
       └─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴──────────────────────────┘

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)

GNU                                                                            2021-03-22                                                                     UPDWTMP(3)