updwtmp(3)

1updwtmp(3)                 Library Functions Manual                 updwtmp(3)
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NAME

6       updwtmp, logwtmp - append an entry to the wtmp file
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LIBRARY

9       System utilities library (libutil, -lutil)
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SYNOPSIS

12       #include <utmp.h>
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14       void updwtmp(const char *wtmp_file, const struct utmp *ut);
15       void logwtmp(const char *line, const char *name, const char *host);
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DESCRIPTION

18       updwtmp() appends the utmp structure ut to the wtmp file.
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20       logwtmp()  constructs  a utmp structure using line, name, host, current
21       time, and current process ID.  Then it calls updwtmp()  to  append  the
22       structure to the wtmp file.
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FILES

25       /var/log/wtmp
26              database of past user logins
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ATTRIBUTES

29       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
30       tributes(7).
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32       ┌───────────────────────────┬───────────────┬──────────────────────────┐
33       │Interface                  │ Attribute     │ Value                    │
34       ├───────────────────────────┼───────────────┼──────────────────────────┤
35       │updwtmp(), logwtmp()       │ Thread safety │ MT-Unsafe sig:ALRM timer │
36       └───────────────────────────┴───────────────┴──────────────────────────┘
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VERSIONS

39       For consistency with the other "utmpx"  functions  (see  getutxent(3)),
40       glibc provides (since glibc 2.1):
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42           #define _GNU_SOURCE          /* See feature_test_macros(7) */
43           #include <utmpx.h>
44           void updwtmpx (const char *wtmpx_file, const struct utmpx *utx);
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46       This  function performs the same task as updwtmp(), but differs in that
47       it takes a utmpx structure as its last argument.
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STANDARDS

50       None.
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HISTORY

53       Solaris, NetBSD.
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