If the terminal is using asynchronous serial data transmission,
tcsendbreak() shall cause transmission of a continuous stream of
zero-valued bits for a specific duration. If duration is 0, it shall
cause transmission of zero-valued bits for at least 0.25 seconds, and not more
than 0.5 seconds. If duration is not 0, it shall send zero-valued bits
for an implementation-defined period of time.
The fildes argument is an open file descriptor associated with a
If the terminal is not using asynchronous serial data transmission, it is
implementation-defined whether tcsendbreak() sends data to generate a
break condition or returns without taking any action.
Attempts to use tcsendbreak() from a process which is a member of a
background process group on a fildes associated with its controlling
terminal shall cause the process group to be sent a SIGTTOU signal. If the
calling process is blocking or ignoring SIGTTOU signals, the process shall be
allowed to perform the operation, and no signal is sent.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html