logwtmp(3) [opendarwin man page]

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(), | 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 4.15 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/.

GNU
								    2017-09-15								UPDWTMP(3)

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

NAME

       login, logout - write utmp and wtmp entries

SYNOPSIS

       #include <utmp.h>

       void login(const struct utmp *ut);

       int logout(const char *ut_line);

       Link with -lutil.

DESCRIPTION

       The utmp file records who is currently using the system.  The wtmp file records all logins and logouts.	See utmp(5).

       The function login() takes the supplied struct utmp, ut, and writes it to both the utmp and the wtmp file.

       The function logout() clears the entry in the utmp file again.

   GNU Details
       More  precisely,  login() takes the argument ut struct, fills the field ut->ut_type (if there is such a field) with the value USER_PROCESS,
       and fills the field ut->ut_pid (if there is such a field) with the process ID of the calling process.  Then it  tries  to  fill	the  field
       ut->ut_line.   It  takes  the  first of stdin, stdout, stderr that is a tty, and stores the corresponding pathname minus a possible leading
       /dev/ into this field, and then writes the struct to the utmp file.  On the other hand, if no tty name was found, this field is filled with
       "???"  and the struct is not written to the utmp file.  After this, the struct is written to the wtmp file.

       The  logout()  function	searches the utmp file for an entry matching the ut_line argument.  If a record is found, it is updated by zeroing
       out the ut_name and ut_host fields, updating the ut_tv timestamp field and setting ut_type (if there is such a field) to DEAD_PROCESS.

RETURN VALUE

       The logout() function returns 1 if the entry was successfully written to the database, or 0 if an error occurred.

FILES

       /var/run/utmp
	      user accounting database, configured through _PATH_UTMP in <paths.h>

       /var/log/wtmp
	      user accounting log file, configured through _PATH_WTMP in <paths.h>

CONFORMING TO

       Not in POSIX.1-2001.  Present on the BSDs.

NOTES

       Note that the member ut_user of struct utmp is called ut_name in BSD.  Therefore, ut_name is defined as an alias for ut_user in <utmp.h>.

SEE ALSO

       getutent(3), utmp(5)

COLOPHON

       This page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

GNU
								    2004-05-06								  LOGIN(3)