These special characters may be active in either canonical or noncanonical input mode, but only when the ISIG flag is set (see Local Modes).
termios.c_cc[VINTR] holds the character itself.
The INTR (interrupt) character raises a SIGINT signal for all processes in the foreground job associated with the terminal. The INTR character itself is then discarded. See Signal Handling, for more information about signals.
Typically, the INTR character is C-c.
termios.c_cc[VQUIT] holds the character itself.
The QUIT character raises a SIGQUIT signal for all processes in the foreground job associated with the terminal. The QUIT character itself is then discarded. See Signal Handling, for more information about signals.
Typically, the QUIT character is C-\.
termios.c_cc[VSUSP] holds the character itself.
The SUSP (suspend) character is recognized only if the implementation supports job control (see Job Control). It causes a SIGTSTP signal to be sent to all processes in the foreground job associated with the terminal. The SUSP character itself is then discarded. See Signal Handling, for more information about signals.
Typically, the SUSP character is C-z.
Few applications disable the normal interpretation of the SUSP character. If your program does this, it should provide some other mechanism for the user to stop the job. When the user invokes this mechanism, the program should send a SIGTSTP signal to the process group of the process, not just to the process itself. See Signaling Another Process.
termios.c_cc[VDSUSP] holds the character itself.
The DSUSP (suspend) character is recognized only if the implementation supports job control (see Job Control). It sends a SIGTSTP signal, like the SUSP character, but not right away---only when the program tries to read it as input. Not all systems with job control support DSUSP; only BSD-compatible systems (including the GNU system).
See Signal Handling, for more information about signals.
Typically, the DSUSP character is C-y.