UPDWTMP

Section: Linux Programmer's Manual (3)
Updated: 2008-07-02
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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);

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 utmp file.

FILES

/var/log/wtmp: database of past user logins

CONFORMING TO

Not in POSIX.1-2001. Present on Solaris, NetBSD, and perhaps other systems.

AVAILABILITY

Both functions are available under glibc2, but not under libc5. However, logwtmp() used to occur in the old libbsd. These days, the logwtmp() function is included in libutil. (Hence you'll need to add -lutil to your compiler command line to get it.)

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

This page is part of release 3.22 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/.