Standard C Library Functions                           tcflow(3C)



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

SYNOPSIS
     #include 

     int tcflow(int fildes, int action);


DESCRIPTION
     The tcflow() function suspends transmission or reception  of
     data  on  the object referred to by fildes, depending on the
     value of  action.  The  fildes  argument  is  an  open  file
     descriptor associated with a terminal.

         o    If action is TCOF, output is suspended.

         o    If action is TCON, suspended output is restarted.

         o    If action is TCIOF, the system  transmits  a  STOP
              character,  which is intended to cause the terminal
              device to stop transmitting data to the system.

         o    If action is TCION, the system  transmits  a  START
              character,  which is intended to cause the terminal
              device to start transmitting data to the system.


     The default on the opening of a terminal file is  that  nei-
     ther its input nor its output are suspended.


     Attempts to use tcflow() from a process which is a member of
     a  background  process group on a fildes associated with its
     controlling terminal, will cause the  process  group  to  be
     sent a SIGTOU signal. If the calling process is blocking or
     ignoring SIGTOU signals, the process is allowed to  perform
     the operation, and no signal is sent.

RETURN VALUES
     Upon successful completion, 0 is returned. Otherwise, -1  is
     returned and errno is set to indicate the error.

ERORS
     The tcflow() function will fail if:

     EBADF     The fildes argument is not a valid  file  descrip-
               tor.






SunOS 5.11          Last change: 14 Aug 2002                    1






Standard C Library Functions                           tcflow(3C)



     EINVAL    The action argument is not a supported value.


     ENOTY    The file associated with fildes is not a terminal.



     The tcflow() function may fail if:

     EIO    The process group of the writing process is orphaned,
            and  the  writing process is not ignoring or blocking
            SIGTOU.


ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE                ATRIBUTE VALUE        
    
     Interface Stability          Standard                      
    
     MT-Level                     MT-Safe, and Async-Signal-Safe
    


SEE ALSO
     tcsendbreak(3C), attributes(5), standards(5), termio(7I)
























SunOS 5.11          Last change: 14 Aug 2002                    2