man/sd_get_seats.3

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   2 .TH "SD_GET_SEATS" "3" "" "systemd 220" "sd_get_seats"
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   8 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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  22 .SH "NAME"
  23 sd_get_seats, sd_get_sessions, sd_get_uids, sd_get_machine_names \- Determine available seats, sessions, logged in users and virtual machines/containers
  24 .SH "SYNOPSIS"
  25 .sp
  26 .ft B
  27 .nf
  28 #include <systemd/sd\-login\&.h>
  29 .fi
  30 .ft
  31 .HP \w'int\ sd_get_seats('u
  32 .BI "int sd_get_seats(char\ ***" "seats" ");"
  33 .HP \w'int\ sd_get_sessions('u
  34 .BI "int sd_get_sessions(char\ ***" "sessions" ");"
  35 .HP \w'int\ sd_get_uids('u
  36 .BI "int sd_get_uids(uid_t\ **" "users" ");"
  37 .HP \w'int\ sd_get_machine_names('u
  38 .BI "int sd_get_machine_names(char\ ***" "machines" ");"
  39 .SH "DESCRIPTION"
  40 .PP
  41 \fBsd_get_seats()\fR
  42 may be used to determine all currently available local seats\&. Returns a
  43 \fBNULL\fR
  44 terminated array of seat identifiers\&. The returned array and all strings it references need to be freed with the libc
  45 \fBfree\fR(3)
  46 call after use\&. Note that instead of an empty array
  47 \fBNULL\fR
  48 may be returned and should be considered equivalent to an empty array\&.
  49 .PP
  50 Similarly,
  51 \fBsd_get_sessions()\fR
  52 may be used to determine all current login sessions\&.
  53 .PP
  54 Similarly,
  55 \fBsd_get_uids()\fR
  56 may be used to determine all Unix users who currently have login sessions\&.
  57 .PP
  58 Similarly,
  59 \fBsd_get_machine_names()\fR
  60 may be used to determine all current virtual machines and containers on the system\&.
  61 .PP
  62 Note that the returned lists are not sorted and in an undefined order\&.
  63 .SH "RETURN VALUE"
  64 .PP
  65 On success,
  66 \fBsd_get_seats()\fR,
  67 \fBsd_get_sessions()\fR,
  68 \fBsd_get_uids()\fR
  69 and
  70 \fBsd_get_machine_names()\fR
  71 return the number of entries in the arrays\&. On failure, these calls return a negative errno\-style error code\&.
  72 .SH "NOTES"
  73 .PP
  74 The
  75 \fBsd_get_seats()\fR,
  76 \fBsd_get_sessions()\fR,
  77 \fBsd_get_uids()\fR
  78 and
  79 \fBsd_get_machine_names()\fR
  80 interfaces are available as a shared library, which can be compiled and linked to with the
  81 \fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
  82 file\&.
  83 .SH "SEE ALSO"
  84 .PP
  85 \fBsystemd\fR(1),
  86 \fBsd-login\fR(3),
  87 \fBsd_session_get_seat\fR(3)