Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
Since glibc 2.21:
In glibc 2.19 and 2.20:
_DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
Up to and including glibc 2.19:
_BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
DESCRIPTIONvhangup() simulates a hangup on the current terminal. This call arranges for other users to have a ``clean'' terminal at login time.
RETURN VALUEOn success, zero is returned. On error, -1 is returned, and errno is set appropriately.
- The calling process has insufficient privilege to call vhangup(); the CAP_SYS_TTY_CONFIG capability is required.
CONFORMING TOThis call is Linux-specific, and should not be used in programs intended to be portable.
COLOPHONThis page is part of release 4.06 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.