tcsendbreak -- Send a Break Condition

SYNOPSIS

 #include <termios.h>

 int tcsendbreak(int fileDescriptor, int duration);
 

DESCRIPTION

tcsendbreak sends a break condition to a terminal.
fileDescriptor
is a file discriptor that refers to an asynchronous communications line.
duration
controls the duration of the break condition in an implementation-defined way. See the POSIX.1 standard for details.
Under MVS OpenEdition, all terminals are pseudoterminals. The tcsendbreak function has no effect on pseudoterminals.

RETURN VALUE

tcsendbreak returns a 0 if successful and a -1 if unsuccessful. If tcsendbreak is called from a background process, with a file descriptor that refers to the controlling terminal for the process, a SIGTTOU signal may be generated. This will cause the function call to be unsuccessful, returning a -1 and setting errno to EINTR. If SIGTTOU is blocked, the function call proceeds normally.

EXAMPLE

The following example illustrates the use of tcsendbreak to transmit a break condition to stdout:
  #include <sys/types.h>
  #include <termios.h>
  #include <unistd.h>
  #include <stdio.h>
  #include <stdlib.h>

  main()
  {
     int ttyDevice = STDOUT_FILENO;
     int time = 15;
     char * lineOut = "Break transmitted to terminal.";

        /* Wait for all data transmission to the terminal to finish */
        /* and then transmit a break condition to the terminal.     */
     if (tcdrain(ttyDevice) != 0) {
        perror("tcdrain error");
        return(EXIT_FAILURE);
     }
     else {
        if (tcsendbreak(STDOUT_FILENO, time) != 0) {
           perror("tcdsendbreak error");
           return(EXIT_FAILURE);
        }
        else
           write(ttyDevice, lineOut, strlen(lineOut) + 1);
     }
     return(EXIT_SUCCESS);
  }

 

RELATED FUNCTIONS

tcflow


Copyright (c) 1998 SAS Institute Inc. Cary, NC, USA. All rights reserved.