TCFLOW(3)                            BSD                             TCFLOW(3)



NAME
     tcflow - Suspend or restart the transmission or reception of data

SYNOPSIS
     #include <termios.h>

     int tcflow (filedes, action)
     int filedes;
     int action;

DESCRIPTION
     The tcflow function suspends transmission or reception of data on the
     object referred to by the filedes argument, depending on the value of the
     action argument, as follows:


     Value     Action

     TCOOFF    Suspend output.

     TCOON     Restart 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.


     The filedes argument specifies an open file descriptor associated with a
     terminal.

     The default on the opening of a terminal file is that neither its input
     or output are suspended.

     Attempts to use the tcflow function from a process that is a member of a
     background process group on a filedes associated with its controlling
     terminal causes the process group to be sent a SIGTTOU signal.  If the
     calling process is blocking or ignoring SIGTTOU signals, the process is
     allowed to perform the operation and no signal is sent.

DIAGNOSTICS
     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
     If the tcflow() function fails, errno will be set to one of the following
     values:

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

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

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

SEE ALSO
     tcdrain(3), tcflush(3), tcsendbreak(3) termios(4)