1UPDWTMP(3) Linux Programmer's Manual UPDWTMP(3)
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6 updwtmp, logwtmp - append an entry to the wtmp file
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9 #include <utmp.h>
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11 void updwtmp(const char *wtmp_file, const struct utmp *ut);
12 void logwtmp(const char *line, const char *name, const char *host);
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14 For logwtmp(), link with -lutil.
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17 updwtmp() appends the utmp structure ut to the wtmp file.
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19 logwtmp() constructs a utmp structure using line, name, host, current
20 time and current process ID. Then it calls updwtmp() to append the
21 structure to the wtmp file.
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24 /var/log/wtmp
25 database of past user logins
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28 For an explanation of the terms used in this section, see
29 attributes(7).
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31 ┌───────────┬───────────────┬──────────────────────────┐
32 │Interface │ Attribute │ Value │
33 ├───────────┼───────────────┼──────────────────────────┤
34 │updwtmp(), │ Thread safety │ MT-Unsafe sig:ALRM timer │
35 │logwtmp() │ │ │
36 └───────────┴───────────────┴──────────────────────────┘
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39 Not in POSIX.1. Present on Solaris, NetBSD, and perhaps other systems.
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42 For consistency with the other "utmpx" functions (see getutxent(3)),
43 glibc provides (since version 2.1):
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45 #include <utmpx.h>
46 void updwtmpx (const char *wtmpx_file, const struct utmpx *utx);
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48 This function performs the same task as updwtmp(), but differs in that
49 it takes a utmpx structure as its last argument.
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52 getutxent(3), wtmp(5)
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55 This page is part of release 5.02 of the Linux man-pages project. A
56 description of the project, information about reporting bugs, and the
57 latest version of this page, can be found at
58 https://www.kernel.org/doc/man-pages/.
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62GNU 2017-09-15 UPDWTMP(3)