tcflow()

perform a flow-control operation on a data stream

Synopsis:

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

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

tcflow() will cause output to be suspended on the device associated with fildes, by using software flow control.

TCOOFFHW

tcflow() will cause output to be suspended on the device associated with fildes, by using hardware flow control.

TCOON

tcflow() will cause output to be resumed on the device associated with fildes, by using software flow control.

TCOONHW

tcflow() will cause output to be resumed on the device associated with fildes, by using hardware flow control.

TCIOFF

tcflow() will 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

tcflow() will cause input to be flow controlled by using hardware flow control.

TCION

tcflow() will cause input to be resumed by sending a START character immediately across the communication line associated with fildes (that is, software flow control).

TCIONHW

tcflow() will cause input to be resumed by using hardware flow control.

Returns:

0

Success

-1

An error occurred. errno is set to indicate the error.

Errors:

EBADF

The argument fildes is invalid.

EINVAL

The argument action is invalid.

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>

void main()
  {
    int fd;

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

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

    close( fd );
  }

Classification:

POSIX 1003.1

See also:

errno, tcdrain(), tcflush(), tcsendbreak()