.TH tcflow() "" "" "termios Macro (termios.h)"
.PC "Control flow on a terminal device"
.B "#include <termios.h>"
\fBint tcflow(\fIfd\^\fB, \fIaction\^\fB)\fR
\fBint \fIfd\^\fB;\fR
\fBint \fIaction\^\fB;\fR
.PP
The
.B termios
macro
.B tcflow()
suspends transmission of data to,
or receiption of data from, the device described by file descriptor
.IR fd .
When a terminal device is opened, by default neither its input nor its
output is suspended.
.I action
gives the action to take, as follows:
.IP \fBTCOOFF\fR
Suspend output.
.IP \fBTCOON\fR
Restart output.
.IP \fBTCIOFF\fR
Transmit character
.BR STOP ,
 which tells the terminal to stop sending data to the system.
.IP \fBTCION\fR
Transmit character
.BR START ,
which tells the terminal to resume sending data to the system.
.PP
These constants are defined in header file
.BR <termios.h> .
.PP
Should all go well,
.B tcflow()
returns zero.
If something goes wrong, it returns \-1 and sets
.B errno
to an appropriate value, as follows:
.IP \fBEBADF\fR
.I fd
is not a valid file descriptor.
.IP \fBEINVAL\fR
.I action
is not set to an appropriate value.
.IP \fBENOTTY\fR
.I fd
does not describe a terminal device.
.SH "See Also"
.Xr "termios" termios
.br
\*(PX Standard, \(sc7.2.2
