In canonical input, the terminal driver recognizes a number of special
characters which perform various control functions. These include the
ERASE character (usually DEL) for editing input, and other editing
characters. The INTR character (normally C-c) for sending a
SIGINT signal, and other signal-raising characters, may be
available in either canonical or noncanonical input mode. All these
characters are described in this section.
The particular characters used are specified in the c_cc member
of the struct termios structure. This member is an array; each
element specifies the character for a particular role. Each element has
a symbolic constant that stands for the index of that element—for
example, VINTR is the index of the element that specifies the INTR
character, so storing '=' in termios.c_cc[VINTR]
specifies ‘=’ as the INTR character.
On some systems, you can disable a particular special character function
by specifying the value _POSIX_VDISABLE for that role. This
value is unequal to any possible character code. See Optional Features in File Support, for more information about how to tell whether the operating
system you are using supports _POSIX_VDISABLE.