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-<H1 class="no-header">curs_add_wch 3x</H1>
+<H1 class="no-header">curs_add_wch 3x 2024-04-13 ncurses 6.4 Library calls</H1>
<PRE>
-<STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
<STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
+<STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
Library calls <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
- <STRONG>add_wch</STRONG>, <STRONG>wadd_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, <STRONG>mvwadd_wch</STRONG>, <STRONG>echo_wchar</STRONG>,
- <STRONG>wecho_wchar</STRONG> - add a complex character and rendition to a
- <STRONG>curses</STRONG> window, then advance the cursor
+ <STRONG>add_wch</STRONG>, <STRONG>wadd_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, <STRONG>mvwadd_wch</STRONG>, <STRONG>echo_wchar</STRONG>, <STRONG>wecho_wchar</STRONG> - add
+ a <EM>curses</EM> complex character to a window and advance the cursor
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
- <STRONG>int</STRONG> <STRONG>add_wch(</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM> <STRONG>);</STRONG>
- <STRONG>int</STRONG> <STRONG>wadd_wch(</STRONG> <STRONG>WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM> <STRONG>);</STRONG>
- <STRONG>int</STRONG> <STRONG>mvadd_wch(</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM> <STRONG>);</STRONG>
- <STRONG>int</STRONG> <STRONG>mvwadd_wch(</STRONG> <STRONG>WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG>
- <STRONG>*</STRONG><EM>wch</EM> <STRONG>);</STRONG>
- <STRONG>int</STRONG> <STRONG>echo_wchar(</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM> <STRONG>);</STRONG>
- <STRONG>int</STRONG> <STRONG>wecho_wchar(</STRONG> <STRONG>WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM> <STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>add_wch(const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>wadd_wch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>mvadd_wch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>mvwadd_wch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
+
+ <STRONG>int</STRONG> <STRONG>echo_wchar(const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>wecho_wchar(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
</PRE><H3><a name="h3-add_wch">add_wch</a></H3><PRE>
- The <STRONG>add_wch</STRONG>, <STRONG>wadd_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, and <STRONG>mvwadd_wch</STRONG> functions
- put the complex character <EM>wch</EM> into the given window at its
- current position, which is then advanced. These functions
- perform wrapping and special-character processing as fol-
- lows:
+ The <STRONG>add_wch</STRONG>, <STRONG>wadd_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, and <STRONG>mvwadd_wch</STRONG> functions put the
+ complex character <EM>wch</EM> into the given window at its current position,
+ which is then advanced. These functions perform wrapping and special-
+ character processing as follows:
+
+ <STRONG>o</STRONG> If <EM>wch</EM> refers to a spacing character, then any previous character
+ at that location is removed. A new character specified by <EM>wch</EM> is
+ placed at that location with rendition specified by <EM>wch</EM>. The
+ cursor then advances after this spacing character, to prepare for
+ writing the next character on the screen.
- <STRONG>o</STRONG> If <EM>wch</EM> refers to a spacing character, then any previ-
- ous character at that location is removed. A new
- character specified by <EM>wch</EM> is placed at that location
- with rendition specified by <EM>wch</EM>. The cursor then
- advances to the next spacing character on the screen.
+ The newly added spacing character is the base of the active complex
+ character. Subsequent non-spacing characters can be combined with
+ this base until another spacing character is written to the screen,
+ or the cursor is moved, e.g., using <STRONG>wmove</STRONG>.
- <STRONG>o</STRONG> If <EM>wch</EM> refers to a non-spacing character, all previous
- characters at that location are preserved. The non-
- spacing characters of <EM>wch</EM> are added to the spacing
- complex character, and the rendition specified by <EM>wch</EM>
- is ignored.
+ <STRONG>o</STRONG> If <EM>wch</EM> refers to a non-spacing character, it is appended to the
+ active complex character, retaining the previous characters at that
+ location. The rendition specified by <EM>wch</EM> is ignored.
- <STRONG>o</STRONG> If the character part of <EM>wch</EM> is a tab, newline,
- backspace or other control character, the window is
- updated and the cursor moves as if <STRONG>addch</STRONG> were called.
+ The cursor is not advanced after adding a non-spacing character.
+ Subsequent calls to add non-spacing characters will update the same
+ position.
+
+ <STRONG>o</STRONG> If the character part of <EM>wch</EM> is a tab, newline, backspace or other
+ control character, the window is updated and the cursor moves as if
+ <STRONG>addch</STRONG> were called.
</PRE><H3><a name="h3-echo_wchar">echo_wchar</a></H3><PRE>
- The <STRONG>echo_wchar</STRONG> function is functionally equivalent to a
- call to <STRONG>add_wch</STRONG> followed by a call to <STRONG>refresh</STRONG>. Similarly,
- the <STRONG>wecho_wchar</STRONG> is functionally equivalent to a call to
- <STRONG>wadd_wch</STRONG> followed by a call to <STRONG>wrefresh</STRONG>. The knowledge
- that only a single character is being output is taken into
- consideration and, for non-control characters, a consider-
- able performance gain might be seen by using the *<STRONG>echo</STRONG>*
+ The <STRONG>echo_wchar</STRONG> function is functionally equivalent to a call to <STRONG>add_wch</STRONG>
+ followed by a call to <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG>. Similarly, the <STRONG>wecho_wchar</STRONG> is
+ functionally equivalent to a call to <STRONG>wadd_wch</STRONG> followed by a call to
+ <STRONG>wrefresh</STRONG>. The knowledge that only a single character is being output
+ is taken into consideration and, for non-control characters, a
+ considerable performance gain might be seen by using the *<STRONG>echo</STRONG>*
functions instead of their equivalents.
</PRE><H3><a name="h3-Line-Graphics">Line Graphics</a></H3><PRE>
- Like <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>, <STRONG>addch_wch</STRONG> accepts symbols which make it
- simple to draw lines and other frequently used special
- characters. These symbols correspond to the same VT100
- line-drawing set as <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>.
-
- <EM>Name</EM> <EM>Unicode</EM> <EM>Default</EM> <EM>Description</EM>
- ----------------------------------------------------------------
- WACS_BLOCK 0x25ae # solid square block
- WACS_BOARD 0x2592 # board of squares
- WACS_BTEE 0x2534 + bottom tee
-
- WACS_BULLET 0x00b7 o bullet
- WACS_CKBOARD 0x2592 : checker board (stipple)
- WACS_DARROW 0x2193 v arrow pointing down
- WACS_DEGREE 0x00b0 ' degree symbol
- WACS_DIAMOND 0x25c6 + diamond
- WACS_GEQUAL 0x2265 > greater-than-or-equal-to
- WACS_HLINE 0x2500 - horizontal line
- WACS_LANTERN 0x2603 # lantern symbol
- WACS_LARROW 0x2190 < arrow pointing left
- WACS_LEQUAL 0x2264 < less-than-or-equal-to
- WACS_LLCORNER 0x2514 + lower left-hand corner
- WACS_LRCORNER 0x2518 + lower right-hand corner
- WACS_LTEE 0x2524 + left tee
- WACS_NEQUAL 0x2260 ! not-equal
- WACS_PI 0x03c0 * greek pi
- WACS_PLMINUS 0x00b1 # plus/minus
- WACS_PLUS 0x253c + plus
- WACS_RARROW 0x2192 > arrow pointing right
- WACS_RTEE 0x251c + right tee
- WACS_S1 0x23ba - scan line 1
- WACS_S3 0x23bb - scan line 3
- WACS_S7 0x23bc - scan line 7
- WACS_S9 0x23bd _ scan line 9
- WACS_STERLING 0x00a3 f pound-sterling symbol
- WACS_TTEE 0x252c + top tee
- WACS_UARROW 0x2191 ^ arrow pointing up
- WACS_ULCORNER 0x250c + upper left-hand corner
- WACS_URCORNER 0x2510 + upper right-hand corner
- WACS_VLINE 0x2502 | vertical line
-
- The wide-character configuration of ncurses also defines
- symbols for thick- and double-lines:
-
- <EM>Name</EM> <EM>Unicode</EM> <EM>Default</EM> <EM>Description</EM>
- ---------------------------------------------------------------------
- WACS_T_ULCORNER 0x250f + thick upper left corner
- WACS_T_LLCORNER 0x2517 + thick lower left corner
- WACS_T_URCORNER 0x2513 + thick upper right corner
- WACS_T_LRCORNER 0x251b + thick lower right corner
- WACS_T_LTEE 0x252b + thick tee pointing right
- WACS_T_RTEE 0x2523 + thick tee pointing left
- WACS_T_BTEE 0x253b + thick tee pointing up
- WACS_T_TTEE 0x2533 + thick tee pointing down
- WACS_T_HLINE 0x2501 - thick horizontal line
- WACS_T_VLINE 0x2503 | thick vertical line
- WACS_T_PLUS 0x254b + thick large plus or crossover
- WACS_D_ULCORNER 0x2554 + double upper left corner
- WACS_D_LLCORNER 0x255a + double lower left corner
- WACS_D_URCORNER 0x2557 + double upper right corner
- WACS_D_LRCORNER 0x255d + double lower right corner
- WACS_D_RTEE 0x2563 + double tee pointing left
- WACS_D_LTEE 0x2560 + double tee pointing right
- WACS_D_BTEE 0x2569 + double tee pointing up
- WACS_D_TTEE 0x2566 + double tee pointing down
- WACS_D_HLINE 0x2550 - double horizontal line
- WACS_D_VLINE 0x2551 | double vertical line
- WACS_D_PLUS 0x256c + double large plus or crossover
+ Like <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG>, <STRONG>addch_wch</STRONG> accepts symbols which make it simple to draw
+ lines and other frequently used special characters. These symbols
+ correspond to the same VT100 line-drawing set as <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG>.
+
+ <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG>
+
+
+ <STRONG>ACS</STRONG> <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>Char</STRONG> <STRONG>Glyph</STRONG> <STRONG>Name</STRONG>
+ ------------------------------------------------------------------------
+ <STRONG>WACS_BLOCK</STRONG> 0x25ae # 0 solid square block
+ <STRONG>WACS_BOARD</STRONG> 0x2592 # h board of squares
+ <STRONG>WACS_BTEE</STRONG> 0x2534 + v bottom tee
+ <STRONG>WACS_BULLET</STRONG> 0x00b7 o ~ bullet
+ <STRONG>WACS_CKBOARD</STRONG> 0x2592 : a checker board (stipple)
+ <STRONG>WACS_DARROW</STRONG> 0x2193 v . arrow pointing down
+ <STRONG>WACS_DEGREE</STRONG> 0x00b0 ' f degree symbol
+ <STRONG>WACS_DIAMOND</STRONG> 0x25c6 + ` diamond
+ <STRONG>WACS_GEQUAL</STRONG> 0x2265 > > greater-than-or-equal-to
+ <STRONG>WACS_HLINE</STRONG> 0x2500 - q horizontal line
+ <STRONG>WACS_LANTERN</STRONG> 0x2603 # i lantern symbol
+ <STRONG>WACS_LARROW</STRONG> 0x2190 < , arrow pointing left
+ <STRONG>WACS_LEQUAL</STRONG> 0x2264 < y less-than-or-equal-to
+ <STRONG>WACS_LLCORNER</STRONG> 0x2514 + m lower left-hand corner
+ <STRONG>WACS_LRCORNER</STRONG> 0x2518 + j lower right-hand corner
+ <STRONG>WACS_LTEE</STRONG> 0x2524 + t left tee
+ <STRONG>WACS_NEQUAL</STRONG> 0x2260 ! | not-equal
+ <STRONG>WACS_PI</STRONG> 0x03c0 * { greek pi
+ <STRONG>WACS_PLMINUS</STRONG> 0x00b1 # g plus/minus
+ <STRONG>WACS_PLUS</STRONG> 0x253c + n plus
+ <STRONG>WACS_RARROW</STRONG> 0x2192 > + arrow pointing right
+ <STRONG>WACS_RTEE</STRONG> 0x251c + u right tee
+ <STRONG>WACS_S1</STRONG> 0x23ba - o scan line 1
+ <STRONG>WACS_S3</STRONG> 0x23bb - p scan line 3
+ <STRONG>WACS_S7</STRONG> 0x23bc - r scan line 7
+ <STRONG>WACS_S9</STRONG> 0x23bd _ s scan line 9
+ <STRONG>WACS_STERLING</STRONG> 0x00a3 f } pound-sterling symbol
+ <STRONG>WACS_TTEE</STRONG> 0x252c + w top tee
+ <STRONG>WACS_UARROW</STRONG> 0x2191 ^ - arrow pointing up
+ <STRONG>WACS_ULCORNER</STRONG> 0x250c + l upper left-hand corner
+ <STRONG>WACS_URCORNER</STRONG> 0x2510 + k upper right-hand corner
+ <STRONG>WACS_VLINE</STRONG> 0x2502 | x vertical line
+
+ The wide-character configuration of <EM>ncurses</EM> also defines symbols for
+ thick lines (<STRONG>acsc</STRONG> "J" to "V"):
+
+ <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG>
+ <STRONG>ACS</STRONG> <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>Char</STRONG> <STRONG>Glyph</STRONG> <STRONG>Name</STRONG>
+ ------------------------------------------------------------------------
+ <STRONG>WACS_T_BTEE</STRONG> 0x253b + V thick tee pointing up
+ <STRONG>WACS_T_HLINE</STRONG> 0x2501 - Q thick horizontal line
+ <STRONG>WACS_T_LLCORNER</STRONG> 0x2517 + M thick lower left corner
+ <STRONG>WACS_T_LRCORNER</STRONG> 0x251b + J thick lower right corner
+ <STRONG>WACS_T_LTEE</STRONG> 0x252b + T thick tee pointing right
+ <STRONG>WACS_T_PLUS</STRONG> 0x254b + N thick large plus
+ <STRONG>WACS_T_RTEE</STRONG> 0x2523 + U thick tee pointing left
+ <STRONG>WACS_T_TTEE</STRONG> 0x2533 + W thick tee pointing down
+ <STRONG>WACS_T_ULCORNER</STRONG> 0x250f + L thick upper left corner
+ <STRONG>WACS_T_URCORNER</STRONG> 0x2513 + K thick upper right corner
+ <STRONG>WACS_T_VLINE</STRONG> 0x2503 | X thick vertical line
+
+ and for double-lines (<STRONG>acsc</STRONG> "A" to "I"):
+
+ <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG>
+ <STRONG>ACS</STRONG> <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>Char</STRONG> <STRONG>Glyph</STRONG> <STRONG>Name</STRONG>
+ ------------------------------------------------------------------------
+ <STRONG>WACS_D_BTEE</STRONG> 0x2569 + H double tee pointing up
+ <STRONG>WACS_D_HLINE</STRONG> 0x2550 - R double horizontal line
+ <STRONG>WACS_D_LLCORNER</STRONG> 0x255a + D double lower left corner
+ <STRONG>WACS_D_LRCORNER</STRONG> 0x255d + A double lower right corner
+ <STRONG>WACS_D_LTEE</STRONG> 0x2560 + F double tee pointing right
+ <STRONG>WACS_D_PLUS</STRONG> 0x256c + E double large plus
+ <STRONG>WACS_D_RTEE</STRONG> 0x2563 + G double tee pointing left
+
+ <STRONG>WACS_D_TTEE</STRONG> 0x2566 + I double tee pointing down
+ <STRONG>WACS_D_ULCORNER</STRONG> 0x2554 + C double upper left corner
+ <STRONG>WACS_D_URCORNER</STRONG> 0x2557 + B double upper right corner
+ <STRONG>WACS_D_VLINE</STRONG> 0x2551 | Y double vertical line
+
+ Unicode's descriptions for these characters differs slightly from
+ <EM>ncurses</EM>, by introducing the term "light" (along with less important
+ details). Here are its descriptions for the normal, thick, and double
+ horizontal lines:
+
+ <STRONG>o</STRONG> U+2500 BOX DRAWINGS LIGHT HORIZONTAL
+
+ <STRONG>o</STRONG> U+2501 BOX DRAWINGS HEAVY HORIZONTAL
+
+ <STRONG>o</STRONG> U+2550 BOX DRAWINGS DOUBLE HORIZONTAL
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on
- success.
+ All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success.
+
+ X/Open Curses does not specify any error conditions. This
+ implementation returns an error
+
+ <STRONG>o</STRONG> if the window pointer is null or
+
+ <STRONG>o</STRONG> if it is not possible to add a complete character in the window.
+
+ The latter may be due to different causes:
+
+ <STRONG>o</STRONG> If <STRONG><A HREF="scrollok.3x.html">scrollok(3x)</A></STRONG> is not enabled, writing a character at the lower
+ right margin succeeds. However, an error is returned because it is
+ not possible to wrap to a new line.
- Functions with a "mv" prefix first perform a cursor move-
- ment using <STRONG>wmove</STRONG>, and return an error if the position is
- outside the window, or if the window pointer is null.
+ <STRONG>o</STRONG> If an error is detected when converting a multibyte character to a
+ sequence of bytes, or if it is not possible to add all of the
+ resulting bytes in the window, an error is returned.
+
+ Functions with a "mv" prefix first perform a cursor movement using
+ <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
+ the window pointer is null.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- Note that <STRONG>add_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, <STRONG>mvwadd_wch</STRONG>, and <STRONG>echo_wchar</STRONG>
- may be macros.
+ Note that <STRONG>add_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, <STRONG>mvwadd_wch</STRONG>, and <STRONG>echo_wchar</STRONG> may be macros.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- All of these functions are described in the XSI Curses
- standard, Issue 4. The defaults specified for line-draw-
- ing characters apply in the POSIX locale.
+ These functions are described in the XSI Curses standard, Issue 4. The
+ defaults specified for line-drawing characters apply in the POSIX
+ locale.
+
+
+</PRE><H3><a name="h3-WACS-Symbols">WACS Symbols</a></H3><PRE>
+ X/Open Curses makes it clear that the WACS_ symbols should be defined
+ as a pointer to <STRONG>cchar_t</STRONG> data, e.g., in the discussion of <STRONG>border_set</STRONG>. A
+ few implementations are problematic:
+
+ <STRONG>o</STRONG> NetBSD curses defines the symbols as a <STRONG>wchar_t</STRONG> within a <STRONG>cchar_t</STRONG>.
+
+ <STRONG>o</STRONG> HP-UX curses equates some of the <STRONG>ACS_</STRONG> symbols to the analogous
+ <STRONG>WACS_</STRONG> symbols as if the <STRONG>ACS_</STRONG> symbols were wide characters. The
+ misdefined symbols are the arrows and other symbols which are not
+ used for line-drawing.
+
+ X/Open Curses does not specify symbols for thick- or double-lines.
+ SVr4 curses implementations defined their line-drawing symbols in terms
+ of intermediate symbols. This implementation extends those symbols,
+ providing new definitions which are not in the SVr4 implementations.
+
+ Not all Unicode-capable terminals provide support for VT100-style
+ alternate character sets (i.e., the <STRONG>acsc</STRONG> capability), with their
+ corresponding line-drawing characters. X/Open Curses did not address
+ the aspect of integrating Unicode with line-drawing characters.
+ Existing implementations of Unix curses (AIX, HP-UX, Solaris) use only
+ the <STRONG>acsc</STRONG> character-mapping to provide this feature. As a result, those
+ implementations can only use single-byte line-drawing characters.
+ <EM>ncurses</EM> 5.3 (2002) provided a table of Unicode values to solve these
+ problems. NetBSD curses incorporated that table in 2010.
+
+ In this implementation, the Unicode values are used instead of the
+ terminal description's <STRONG>acsc</STRONG> mapping as discussed in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> for the
+ environment variable <EM>NCURSES</EM><STRONG>_</STRONG><EM>NO</EM><STRONG>_</STRONG><EM>UTF8</EM><STRONG>_</STRONG><EM>ACS</EM>. In contrast, for the same
+ cases, the line-drawing characters described in <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG> will use only
+ the ASCII default values.
- X/Open Curses makes it clear that the WACS_ symbols should
- be defined as a pointer to <STRONG>cchar_t</STRONG> data, e.g., in the dis-
- cussion of <STRONG>border_set</STRONG>. A few implementations are problem-
- atic:
+ Having Unicode available does not solve all of the problems with line-
+ drawing for curses:
- <STRONG>o</STRONG> NetBSD curses defines the symbols as a <STRONG>wchar_t</STRONG> within
- a <STRONG>cchar_t</STRONG>.
+ <STRONG>o</STRONG> The closest Unicode equivalents to the VT100 graphics <EM>S1</EM>, <EM>S3</EM>, <EM>S7</EM>
+ and <EM>S9</EM> frequently are not displayed at the regular intervals which
+ the terminal used.
- <STRONG>o</STRONG> HPUX curses equates some of the <EM>ACS</EM><STRONG>_</STRONG> symbols to the
- analogous <EM>WACS</EM><STRONG>_</STRONG> symbols as if the <EM>ACS</EM><STRONG>_</STRONG> symbols were
- wide characters. The misdefined symbols are the
- arrows and other symbols which are not used for line-
- drawing.
+ <STRONG>o</STRONG> The <EM>lantern</EM> is a special case. It originated with the AT&T 4410
+ terminal in the early 1980s. There is no accessible documentation
+ depicting the lantern symbol on the AT&T terminal.
- X/Open Curses does not define symbols for thick- or dou-
- ble-lines. SVr4 curses implementations defined their
- line-drawing symbols in terms of intermediate symbols.
- This implementation extends those symbols, providing new
- definitions which are not in the SVr4 implementations.
+ Lacking documentation, most readers assume that a <EM>storm</EM> <EM>lantern</EM> was
+ intended. But there are several possibilities, all with problems.
+
+ Unicode 6.0 (2010) does provide two lantern symbols: U+1F383 and
+ U+1F3EE. Those were not available in 2002, and are irrelevant
+ since they lie outside the BMP and as a result are not generally
+ available in terminals. They are not storm lanterns, in any case.
+
+ Most <EM>storm</EM> <EM>lanterns</EM> have a tapering glass chimney (to guard against
+ tipping); some have a wire grid protecting the chimney.
+
+ For the tapering appearance, U+2603 was adequate. In use on a
+ terminal, no one can tell what the image represents. Unicode calls
+ it a snowman.
+
+ Others have suggested these alternatives: <section> U+00A7 (section
+ mark), <Theta> U+0398 (theta), <Phi> U+03A6 (phi), <delta> U+03B4
+ (delta), U+2327 (x in a rectangle), U+256C (forms double vertical
+ and horizontal), and U+2612 (ballot box with x).
+
+
+</PRE><H3><a name="h3-Complex-Characters">Complex Characters</a></H3><PRE>
+ The complex character type <STRONG>cchar_t</STRONG> can store more than one wide
+ character (<STRONG>wchar_t</STRONG>). The X/Open Curses description does not mention
+ this possibility, describing only the cases where <EM>wch</EM> is a spacing
+ character or a non-spacing character.
+
+ This implementation assumes that <EM>wch</EM> is constructed using <STRONG><A HREF="curs_getcchar.3x.html">setcchar(3x)</A></STRONG>,
+ and in turn that the result
+
+ <STRONG>o</STRONG> contains at most one spacing character in the beginning of its list
+ of wide characters, and zero or more non-spacing characters or
+
+ <STRONG>o</STRONG> may hold one non-spacing character.
+
+ In the latter case, <EM>ncurses</EM> adds the non-spacing character to the
+ active (base) spacing character.
+
+
+</PRE><H3><a name="h3-TABSIZE">TABSIZE</a></H3><PRE>
+ The <STRONG>TABSIZE</STRONG> variable is implemented in SVr4 and other versions of
+ <EM>curses</EM>, but is not specified by X/Open Curses (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>).
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>,
- <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG>putwc(3)</STRONG>
+ <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG> describes comparable functions of the <EM>ncurses</EM> library in
+ its non-wide-character configuration.
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_addwstr.3x.html">curs_addwstr(3x)</A></STRONG>, <STRONG><A HREF="curs_add_wchstr.3x.html">curs_add_wchstr(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>,
+ <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>, <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>,
+ <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>putwc(3)</STRONG>
- <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
+
+ncurses 6.4 2024-04-13 <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
-<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-PORTABILITY">PORTABILITY</a>
+<ul>
+<li><a href="#h3-WACS-Symbols">WACS Symbols</a></li>
+<li><a href="#h3-Complex-Characters">Complex Characters</a></li>
+<li><a href="#h3-TABSIZE">TABSIZE</a></li>
+</ul>
+</li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
projects / ncurses.git / blobdiff