tcflush(3) - NetBSD Manual Pages

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TCSENDBREAK(3)          NetBSD Library Functions Manual         TCSENDBREAK(3)


NAME

     tcsendbreak, tcdrain, tcflush, tcflow -- line control functions


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #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

     The tcdrain function waits until all output written to the terminal ref-
     erenced 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 termi-
             nal to stop transmitting data to the system.  (See the descrip-
             tion of IXOFF in the `Input Modes' section of termios(4)).

     TCION   Transmit a START character, which is intended to cause the termi-
             nal to start transmitting data to the system.  (See the descrip-
             tion 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

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


ERRORS

     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

     tcsetattr(3), termios(4)


STANDARDS

     The tcsendbreak, tcdrain, tcflush and tcflow functions are expected to be
     compliant with the IEEE Std 1003.1-1988 (``POSIX.1'') specification.

NetBSD 5.2                       June 4, 1993                       NetBSD 5.2