NAME    [Toc]    [Back]

     tcdrain, tcflow, tcflush, tcsendbreak - line  control  functions

SYNOPSIS    [Toc]    [Back]

     #include <termios.h>

     int
     tcdrain(int fd);

     int
     tcflow(int fd, int action);

     int
     tcflush(int fd, int action);

     int
     tcsendbreak(int fd, int len);

DESCRIPTION    [Toc]    [Back]

     The tcdrain() function waits until all output written to the
terminal
     referenced by fd has been transmitted to the terminal.

     The tcflow() function suspends transmission of  data  to  or
the reception
     of  data from the terminal referenced by fd depending on the
value of
     action.  The value of action must be one of the following:

     TCOOFF  Suspend output.

     TCOON   Restart suspended output.

     TCIOFF  Transmit a STOP  character,  which  is  intended  to
cause the terminal
  to  stop transmitting data to the system.  (See
the description
 of  IXOFF  in  the  `Input  Modes'  section  of
termios(4)).

     TCION    Transmit  a  START  character, which is intended to
cause the terminal
 to start transmitting data to the system.   (See
the description
  of  IXOFF  in  the  `Input  Modes'  section of
termios(4)).

     The tcflush() function discards any data written to the terminal referenced
  by fd which has not been transmitted to the terminal,
or any data
     received from the terminal but not yet  read,  depending  on
the value of
     action.  The value of action must be one of the following:

     TCIFLUSH   Flush data received but not read.

     TCOFLUSH   Flush data written but not transmitted.

     TCIOFLUSH   Flush  both  data received but not read and data
written but not
                transmitted.

     The tcsendbreak() function transmits a continuous stream  of
zero-valued
     bits  for four-tenths of a second to the terminal referenced
by fd.  The
     len parameter is ignored in this implementation.

RETURN VALUES    [Toc]    [Back]

     Upon successful completion, all of these functions return  a
value of zero.

ERRORS    [Toc]    [Back]

     If any error occurs, a value of -1 is returned and the global variable
     errno is set to indicate the error, as follows:

     [EBADF]       The fd argument is not a valid  file  descriptor.

     [EINVAL]      The action argument is not a proper value.

     [ENOTTY]      The file associated with fd is not a terminal.

     [EINTR]       A signal interrupted the tcdrain() function.

SEE ALSO    [Toc]    [Back]

     tcsetattr(3), termios(4)

STANDARDS    [Toc]    [Back]

     The tcdrain(), tcflow(), tcflush(), and tcsendbreak()  functions are expected
  to  be  compliant  with  the  IEEE  Std  1003.1-1988
(``POSIX'') specification.


OpenBSD     3.6                           March      4,      1992