1VHANGUP(2)                    System Calls Manual                   VHANGUP(2)
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NAME

6       vhangup - virtually ``hangup'' the current control terminal
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SYNOPSIS

9       vhangup()
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DESCRIPTION

12       Vhangup is used by the initialization process init(8) (among others) to
13       arrange that users are given “clean”' terminals at login,  by  revoking
14       access  of  the  previous  users' processes to the terminal.  To effect
15       this, vhangup searches the system tables for references to the  control
16       terminal  of  the invoking process, revoking access permissions on each
17       instance of the terminal that it finds.  Further attempts to access the
18       terminal  by  the  affected  processes  will  yield i/o errors (EBADF).
19       Finally, a hangup signal (SIGHUP) is sent to the process group  of  the
20       control terminal.
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SEE ALSO

23       init (8)
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BUGS

26       Access to the control terminal via /dev/tty is still possible.
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28       This call should be replaced by an automatic mechanism that takes place
29       on process exit.
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334th Berkeley Distribution        June 30, 1985                      VHANGUP(2)