updwtmp

Section: C Library Functions (3)
Updated: 2022-12-15
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NAME

updwtmp, logwtmp - append an entry to the wtmp file

LIBRARY

System utilities library (libutil, -lutil)

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);

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

STANDARDS

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 glibc 2.1):

#define _GNU_SOURCE /* See feature_test_macros(7) */ #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.

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Time: 18:01:43 GMT, April 26, 2024