-If the character part of \fIwch\fP is
-a tab, newline, backspace or other control character,
-the window is updated and the cursor moves as if \fBaddch\fP were called.
-.SS echo_wchar
-The \fBecho_wchar\fP
-function is functionally equivalent to a call to
-\fBadd_wch\fP
-followed by a call to
-\fBrefresh\fP(3X).
-Similarly, the
-\fBwecho_wchar\fP
-is functionally equivalent to a call to
-\fBwadd_wch\fP
-followed by a call to
-\fBwrefresh\fP.
-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 *\fBecho\fP* functions instead of their equivalents.
-.SS Line Graphics
-Like \fBaddch\fP(3X),
-\fBaddch_wch\fP 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
-\fBaddch\fP(3X).
+if it was at the bottom of the scrolling region,
+and if \fB\%scrollok\fP(3X) is enabled for
+.IR win ,
+the scrolling region scrolls up one line.
+.PP
+If
+.I wch
+is a
+backspace,
+carriage return,
+line feed,
+or
+tab,
+the cursor moves appropriately within the window.
+.bP
+Backspace moves the cursor one character left;
+at the left margin of a window,
+it does nothing.
+.bP
+Carriage return moves the cursor to the left margin on the current line
+of the window.
+.bP
+Line feed does a \fB\%clrtoeol\fP(3X),
+then advances as if from the right margin.
+.bP
+Tab advances the cursor to the next tab stop
+(possibly on the next line);
+these are placed at every eighth column by default.
+Alter the tab interval with the
+.B \%TABSIZE
+extension;
+see \fB\%curs_variables\fP(3X).
+.PP
+If
+.I wch
+is any other nonprintable character,
+it is drawn in printable form using the same convention as
+\fB\%wunctrl\fP(3X).
+.PP
+Calling \fB\%win_wch\fP(3X) on the location of a nonprintable character
+does not return the character itself,
+but its \fB\%wunctrl\fP(3X) representation.
+.SS wecho_wchar
+.B \%echo_wchar
+and
+.B \%wecho_wchar
+are equivalent to calling
+.RB \%( w ) add_wch
+followed by
+.RB \%( w ) refresh .
+.I curses
+interprets these functions as a hint that only a single (complex)
+character is being output;
+for non-control characters,
+a considerable performance gain may be enjoyed by employing them.
+.\" TODO: Combine the following with the "Line Drawing" subsection of
+.\" terminfo(5) and replace this with a cross reference there.
+.SS "Forms-Drawing Characters"
+.I curses
+defines macros starting with
+.B \%WACS_
+that can be used with
+.B \%wadd_wch
+to write line-drawing and other special characters to the screen.
+.I \%ncurses
+terms these
+.I "forms-drawing characters."
+The ACS default listed below is used if the
+.B \%acs_chars
+.RB ( \%acsc )
+.I \%term\%info
+capability does not define a terminal-specific replacement for it,
+or if the terminal and locale configuration requires Unicode to access
+these characters but the library is unable to use Unicode.
+The \*(``acsc char\*('' column corresponds to how the characters are
+specified in the
+.B \%acs_chars
+.RB ( \%acsc )
+string capability,
+and the characters in it may appear on the screen if the terminal type's
+database entry incorrectly advertises ACS support.
+The name \*(``ACS\*('' originates in the Alternate Character Set feature
+of the DEC VT100 terminal.
projects / ncurses.git / blobdiff