tcflow()

Perform a flow-control operation on a data stream

Synopsis:

#include <termios.h>

int tcflow( int fildes, 
            int action );

Arguments:

fildes

A file descriptor that's associated with the data stream that you want to perform the operation on.

action

The action you want to perform; see below.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The tcflow() function performs a flow-control operation on the data stream associated with fildes, depending on the values in action.

At least the following actions are defined in <termios.h>:

TCOOFF

Use software flow control to suspend output on the device associated with fildes.

TCOOFFHW

Use hardware flow control to suspend output on the device associated with fildes.

TCOON

Use software flow control to resume output on the device associated with fildes.

TCOONHW

Use hardware flow control to resume output on the device associated with fildes.

TCIOFF

Cause input to be flow-controlled by sending a STOP character immediately across the communication line associated with fildes, (that is, software flow control).

TCIOFFHW

Cause input to be flow-controlled by using hardware control.

TCION

Resume input by sending a START character immediately across the communication line associated with fildes (that is, software flow control).

TCIONHW

Cause input to be resumed by using hardware flow control.

Returns:

0

Success.

-1

An error occurred (errno is set).

Errors:

EBADF

Invalid fildes argument.

EINVAL

Invalid action argument.

ENOSYS

The resource manager associated with fildes doesn't support this call.

ENOTTY

The argument fildes doesn't refer to a terminal device.

Examples:

#include <termios.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

int main( void )
  {
    int fd;

    fd = open( "/dev/ser1", O_RDWR );

    /* Resume output on flow-controlled device */
    tcflow( fd, TCOON );

    close( fd );
    return EXIT_SUCCESS;
  }

Classification:

POSIX 1003.1

See also:

tcdrain(), tcflush(), tcsendbreak()