updwtmp(3)

GNU

2017-09-15

Aliases: logwtmp(3), logwtmp(3), logwtmp(3), logwtmp(3), logwtmp(3), logwtmp(3), logwtmp(3), logwtmp(3), updwtmpx(3), updwtmpx(3), updwtmpx(3), updwtmpx(3), updwtmpx(3), updwtmpx(3)

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Linux kernel and C library user-space interface documentation

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
	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.

REFERENCED BY

utmp(5)