man3/updwtmp.3

   1 .\" Copyright 1997 Nicolás Lichtmaier <nick@debian.org>
   2 .\" Created Wed Jul  2 23:27:34 ART 1997
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  25 .\" Added info on availability, aeb, 971207
  26 .\" Added -lutil remark, 030718
  27 .\" 2008-07-02, mtk, document updwtmpx()
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  29 .TH UPDWTMP 3  2017-09-15 "GNU" "Linux Programmer's Manual"
  30 .SH NAME
  31 updwtmp, logwtmp \- append an entry to the wtmp file
  32 .SH SYNOPSIS
  33 .nf
  34 .B #include <utmp.h>
  35 .PP
  36 .BI "void updwtmp(const char *" wtmp_file ", const struct utmp *" ut );
  37 .BI "void logwtmp(const char *" line ", const char *" name \
  38 ", const char *" host );
  39 .fi
  40 .PP
  41 For
  42 .BR logwtmp (),
  43 link with \fI\-lutil\fP.
  44 .SH DESCRIPTION
  45 .BR updwtmp ()
  46 appends the utmp structure
  47 .I ut
  48 to the wtmp file.
  49 .PP
  50 .BR logwtmp ()
  51 constructs a utmp structure using
  52 .IR line ", " name ", " host ,
  53 current time and current process ID.
  54 Then it calls
  55 .BR updwtmp ()
  56 to append the structure to the wtmp file.
  57 .SH FILES
  58 .TP
  59 .I /var/log/wtmp
  60 database of past user logins
  61 .SH ATTRIBUTES
  62 For an explanation of the terms used in this section, see
  63 .BR attributes (7).
  64 .TS
  65 allbox;
  66 lb lb lbw24
  67 l l l.
  68 Interface       Attribute       Value
  69 T{
  70 .BR updwtmp (),
  71 .br
  72 .BR logwtmp ()
  73 T}      Thread safety   MT-Unsafe sig:ALRM timer
  74 .TE
  75 .sp 1
  76 .SH CONFORMING TO
  77 Not in POSIX.1.
  78 Present on Solaris, NetBSD, and perhaps other systems.
  79 .SH NOTES
  80 For consistency with the other "utmpx" functions (see
  81 .BR getutxent (3)),
  82 glibc provides (since version 2.1):
  83 .PP
  84 .in +4n
  85 .EX
  86 .B #include <utmpx.h>
  87 .BI "void updwtmpx (const char *" wtmpx_file ", const struct utmpx *" utx );
  88 .EE
  89 .in
  90 .PP
  91 This function performs the same task as
  92 .BR updwtmp (),
  93 but differs in that it takes a
  94 .I utmpx
  95 structure as its last argument.
  96 .SH SEE ALSO
  97 .BR getutxent (3),
  98 .BR wtmp (5)