HP-UX Reference (11i v1 05/09) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

t
termio(7) termio(7)
If the designated process has exited, the
SIGIO signal is not sent to any pro-
cess.
If the integer referenced by arg is 0, system asynchronous
I/O is disabled.
The default on open of a terminal device file is that system asynchronous
I/O is
disabled.
FIOGSAIOSTAT The integer referenced by arg is set to 1 if system asynchronous
I/O is enabled.
Otherwise, the integer referenced by arg is set to 0.
FIOSSAIOOWN Set the process ID that will receive the
SIGIO signals due to system asynchro-
nous
I/O to the value of the integer referenced by arg. If no process can be found
corresponding to that specified by the integer referenced by arg, the call returns
−1 with
errno set to ESRCH. A user with appropriate privileges can designate
that any process receive the
SIGIO signals. If the request is not made by a
user with appropriate privileges and the calling process does not either designate
that itself or another process whose real, saved, or effective user
ID matches its
real or effective user
ID
or the calling process does not designate a process that is
a descendant of the calling process to receive the
SIGIO signals, the call
returns −1 with errno set to EPERM.
If the designated process subsequently exits, the SIGIO signal is not sent to
any process.
The default on open of a terminal device file is that the process performing the
first open is set to receive the SIGIO signals.
FIOGSAIOOWN The integer referenced by arg is set to the process ID designated to receive
SIGIO signals.
Line Control IOCTL Commands
Several ioctl() system calls control input and output. Some of these calls have the form:
ioctl (fildes, command, arg)
int arg;
Commands using this form are:
TCSBRK Wait for the output to drain. If arg is 0, send a break (zero bits for at least 0.25
seconds). The tcsendbreak() function performs the same function (see
tcsendbreak(3C)).
TCXONC Start/stop control. If arg is 0, suspend output; if 1, restart suspended output; if 2,
transmit a STOP character; if 3, transmit a START character. If any other value is
given for arg, the call returns −1 with errno set to EINVAL.
The tcflow() func-
tion performs the same functions (see tcflow(3C)).
TCFLSH If arg is 0, flush the input queue; if 1, flush the output queue; if 2, flush both the input
and output queues. If any other value is given for arg, the call returns −1 with
errno set to EINVAL. The tcflush() function performs the same functions (see
tcflush(3C)).
Sending a BREAK is accomplished by holding the data transmit line at a SPACE or logi-
cal zero condition for at least 0.25 seconds. During this interval, data can be sent to
the device, but because of serial data interface limitations, the BREAK takes pre-
cedence over all data. Thus, all data sent to a device during a BREAK is lost. This
includes system-generated XON/XOFF characters used for input flow control. Note also
that a delay in transmission of the XOFF flow control character until after the BREAK
is terminated could still result in data overflow because the flow control character may
not be sent soon enough.
Other calls have the form:
ioctl (fildes, command, arg)
int *arg;
Commands using this form are:
FIONREAD Returns in the integer referenced by arg the number of characters immediately read-
able from the terminal device file. This command is allowed from a background
Section 7−−188 Hewlett-Packard Company − 14 − HP-UX 11i Version 1: September 2005