HP 9000 Series 300 Tutorials Manual page 210

Display Highlighting
curses supports nine highlighting attributes, each of which has a
corresponding 32-bit integer constant named in the include file <curses. h>.
The value of each constant is selected such that one bit (corresponding to the
attribute) in the 32-bit integer is set while all other bits are cleared. Below
is a list of the nine attributes with their corresponding enable-bit positions.
The name and octal value of each constant is also shown (note that only eleven
digits are needed to represent the 32-bit value; the leading zero identifies the
constant as an octal value).
• Standout (bit 23):
A_STANDOUT
=
000040000000
• Underlining (bit 24):
A_UNDERLINE
=
000100000000
• Inverse Video (bit 25):
A_REVERSE
=
000200000000
• Blinking (bit 26):
A_BLINK
=
000400000000
• Dim (bit 27):
A_DIM
=
001000000000
• Bold (bit 28):
A_BOLD
=
002000000000
• Invisible (bit 29):
A_REVERSE
=
004000000000
• No print or display (bit 30):
A_PROTECT
=
010000000000
• Alternate Character Set (bit 31):
A_ALTCHARSET
=
020000000000
addch
and
waddchr
store window characters as 32-bit data words where the
lower eight bits (0-7) of each word contain the character code and the upper
sixteen bits (16-31), when set, enable the corresponding display highlighting
attributes when that character is displayed on a terminal. Each attribute bit
corresponds to one of the highlighting functions listed above. Obviously, any
selected highlighting feature that is not available on a given terminal cannot be
used even though the capability is standard fare for curses. However, when
a requested attribute is not available on a given terminal, curses attempts
to identify and use a suitable substitute. If none is possible, the attribute is
ignored.
1-12 Using Curses and Terminfo