updwtmp man page

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).

InterfaceAttributeValue
updwtmp(),
logwtmp()
Thread safetyMT-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)

Colophon

This page is part of release 4.08 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/.

Referenced By

utempter(3), utmp(5).

logwtmp(3) and updwtmpx(3) are aliases of updwtmp(3).

2015-04-19 GNU Linux Programmer's Manual