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<!-- Manpage converted by man2html 3.0.1 -->
-<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
+<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE>
<H2>NAME</H2><PRE>
- <STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>,
- <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>
+ <STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>,
+ <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>
- <STRONG>curses</STRONG> color manipulation routines
</PRE>
<H2>DESCRIPTION</H2><PRE>
<STRONG>Overview</STRONG>
- <STRONG>curses</STRONG> support color attributes on terminals with that
- capability. To use these routines <STRONG>start_color</STRONG> must be
+ <STRONG>curses</STRONG> support color attributes on terminals with that ca-
+ pability. To use these routines <STRONG>start_color</STRONG> must be
called, usually right after <STRONG>initscr</STRONG>. Colors are always
used in pairs (referred to as color-pairs). A color-pair
consists of a foreground color (for characters) and a
nition of a color. The routines <STRONG>has_colors</STRONG> and
<STRONG>can_change_color</STRONG> return <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>, depending on
whether the terminal has color capabilities and whether
- the programmer can change the colors. The routine
- <STRONG>color_content</STRONG> allows a programmer to extract the amounts
- of red, green, and blue components in an initialized
- color. The routine <STRONG>pair_content</STRONG> allows a programmer to
- find out how a given color-pair is currently defined.
+ the programmer can change the colors. The routine <STRONG>col-</STRONG>
+ <STRONG>or_content</STRONG> allows a programmer to extract the amounts of
+ red, green, and blue components in an initialized color.
+ The routine <STRONG>pair_content</STRONG> allows a programmer to find out
+ how a given color-pair is currently defined.
<STRONG>Routine</STRONG> <STRONG>Descriptions</STRONG>
The <STRONG>start_color</STRONG> routine requires no arguments. It must be
<STRONG>COLOR_PAIRS-1</STRONG>.
- The value of the second and third arguments must be
- between 0 and <STRONG>COLORS</STRONG> (the 0 color pair is wired to
- white on black and cannot be changed).
+ between 0 and <STRONG>COLORS</STRONG>. Color pair 0 is assumed to be
+ white on black, but is actually whatever the terminal
+ implements before color is initialized. It cannot be
+ modified by the application.
If the color-pair was previously initialized, the screen
is refreshed and all occurrences of that color-pair are
As an extension, ncurses allows you to set color pair 0
via the <STRONG>assume_default_colors</STRONG> routine, or to specify the
- use of default colors (color number <STRONG>-1</STRONG>) if you first
- invoke the <STRONG>use_default_colors</STRONG> routine.
+ use of default colors (color number <STRONG>-1</STRONG>) if you first in-
+ voke the <STRONG>use_default_colors</STRONG> routine.
The <STRONG>init_color</STRONG> routine changes the definition of a color.
It takes four arguments: the number of the color to be
<STRONG>TRUE</STRONG> if the terminal can manipulate colors; otherwise, it
returns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal-
independent programs. For example, a programmer can use
- it to decide whether to use color or some other video
- attribute.
+ it to decide whether to use color or some other video at-
+ tribute.
The <STRONG>can_change_color</STRONG> routine requires no arguments. It
returns <STRONG>TRUE</STRONG> if the terminal supports colors and can
about the amounts of red, green, and blue components in
the given color. The value of the first argument must be
between 0 and <STRONG>COLORS</STRONG>. The values that are stored at the
- addresses pointed to by the last three arguments are
- between 0 (no component) and 1000 (maximum amount of com-
- ponent).
+ addresses pointed to by the last three arguments are be-
+ tween 0 (no component) and 1000 (maximum amount of compo-
+ nent).
The <STRONG>pair_content</STRONG> routine allows programmers to find out
what colors a given color-pair consists of. It requires
an <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than
<STRONG>ERR</STRONG>") upon successful completion.
+ X/Open defines no error conditions. This implementation
+ will return <STRONG>ERR</STRONG> on attempts to use color values outside
+ the range 0 to COLORS-1 (except for the default colors ex-
+ tension), or use color pairs outside the range 0 to COL-
+ OR_PAIR-1. Color values used in <STRONG>init_color</STRONG> must be in the
+ range 0 to 1000. An error is returned from all functions
+ if the terminal has not been initialized. An error is re-
+ turned from secondary functions such as <STRONG>init_pair</STRONG> if
+ <STRONG>start_color</STRONG> was not called.
+
+ <STRONG>init_color</STRONG>
+ returns an error if the terminal does not sup-
+ port this feature, e.g., if the <EM>initial-</EM>
+ <EM>ize</EM><STRONG>_</STRONG><EM>color</EM> capability is absent from the termi-
+ nal description.
+
+ <STRONG>start_color</STRONG>
+ returns an error If the color table cannot be
+ allocated.
+
</PRE>
<H2>NOTES</H2><PRE>
In the <EM>ncurses</EM> implementation, there is a separate color
- activation flag, color palette, color pairs table, and
- associated COLORS and COLOR_PAIRS counts for each screen;
+ activation flag, color palette, color pairs table, and as-
+ sociated COLORS and COLOR_PAIRS counts for each screen;
the <STRONG>start_color</STRONG> function only affects the current screen.
The SVr4/XSI interface is not really designed with this in
mind, and historical implementations may use a single
mums for <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>.
The <STRONG>init_pair</STRONG> routine accepts negative values of fore-
- ground and background color to support the
- <STRONG>use_default_colors</STRONG> extension, but only if that routine has
- been first invoked.
+ ground and background color to support the <STRONG>use_de-</STRONG>
+ <STRONG>fault_colors</STRONG> extension, but only if that routine has been
+ first invoked.
The assumption that <STRONG>COLOR_BLACK</STRONG> is the default background
- color for all terminals can be modified using the
- <STRONG>assume_default_colors</STRONG> extension,
+ color for all terminals can be modified using the <STRONG>as-</STRONG>
+ <STRONG>sume_default_colors</STRONG> extension.
+ This implementation checks the pointers, e.g., for the
+ values returned by <STRONG>color_content</STRONG> and <STRONG>pair_content</STRONG>, and
+ will treat those as optional parameters when null.
</PRE>
- <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
+
<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE>
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