Logwtmp (3) Linux Manual 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).

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.

Colophon

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logwtmp (3) Linux Manual Page