-APUE-:
fig18.11, example of tcgetattr and tcsetattr, CSIZE.
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fig18.12, implementation of POSIX.1 ctermid function.
fig18.13, implemantation of POSIX.1 isatty function.
fig18.14, test the isatty function.
fig18.15, implementation of POSIX.1 ttyname function.
fig18.16, test the ttyname function.
-APUE-:
fig18.17, implementation of getpass function.
fig18.18, call the getpass function.
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fig18.20, set terminal mode to cbreak or raw.
fig18.21, test raw and cbreak terminal modes.
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fig18.22, print window size.