NAME

tcflow − Perform flow control functions

SYNOPSIS

#include <termios.h>
int tcflow(
        int filedes,
        int action );

LIBRARY

Standard C Library (libc)

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

tcflow():  XPG4, XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

PARAMETERS

filedes
Specifies an open file descriptor.

action
Specifies one of the following:

TCOOFF
Suspend output.

TCOON
Restart suspended output.

TCIOFF
Transmit a STOP character, which is intended to cause the terminal device to stop transmitting data to the system.

TCION
Transmit a START character, which is intended to cause the terminal device to start transmitting data to the system.

DESCRIPTION

The tcflow() function suspends transmission or reception of data on the object referred to by the filedes parameter, depending on the value of the action parameter. 

A process group is sent a SIGTTOU signal if the tcflow() function is called from one of its member processes. If the calling process is blocking or ignoring SIGTTOU signals, the process is allowed to perform the operation and no signal is sent. 

RETURN VALUES

Upon successful completion, a value of 0 (zero) is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error. 

ERRORS

The tcflow() function sets errno to the specified values for the following conditions:

[EBADF]
The filedes parameter does not specify a valid file descriptor. 

[EINVAL]
The action parameter is not a supported value. 

[ENOTTY]
The file associated with the filedes parameter is not a terminal. 

SEE ALSO

Functions: tcdrain(3), tcflush(3), tcsendbreak(3)

Files: termios(4)

Standards: standards(5)