- The XSI Curses standard, Issue 4 describes these func-
- tions. It states that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a
- null pointer if unsuccessful, but does not define any er-
- ror conditions. This implementation checks for three cas-
- es:
-
- <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the
- case that X/Open Curses documented.
-
- <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 con-
- trol code. If <STRONG>use_legacy_coding</STRONG> has been called with
- a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG> returns the parameter, i.e., a
- one-character string with the parameter as the first
- character. Otherwise, it returns "~@", "~A", etc.,
- analogous to "^@", "^A", C0 controls.
-
- X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be
- called before initializing curses. This implementa-
- tion permits that, and returns the "~@", etc., values
- in that case.
-
- <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG>
- returns a null pointer.
-
- The strings returned by <STRONG>unctrl</STRONG> in this implementation are
- determined at compile time, showing C1 controls from the
- upper-128 codes with a "~" prefix rather than "^". Other
- implementations have different conventions. For example,
- they may show both sets of control characters with "^",
- and strip the parameter to 7 bits. Or they may ignore C1
- controls and treat all of the upper-128 codes as print-
- able. This implementation uses 8 bits but does not modify
- the string to reflect locale. The <STRONG>use_legacy_coding</STRONG> func-
- tion allows the caller to change the output of <STRONG>unctrl</STRONG>.
-
- Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to
- change the output of <STRONG>keyname</STRONG>, i.e., it determines whether
- to use the "M-" prefix for "meta" keys (codes in the range
- 128 to 255). Both <STRONG>use_legacy_coding</STRONG> and <STRONG>meta</STRONG> succeed only
- after curses is initialized. X/Open Curses does not docu-
- ment the treatment of codes 128 to 159. When treating
- them as "meta" keys (or if <STRONG>keyname</STRONG> is called before ini-
- tializing curses), this implementation returns strings
- "M-^@", "M-^A", etc.
+ The XSI Curses standard, Issue 4 describes these functions. It states
+ that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but
+ does not define any error conditions. This implementation checks for
+ three cases:
+
+ <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
+ X/Open Curses documented.
+
+ <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
+ <STRONG>use_legacy_coding</STRONG> has been called with a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG> re-
+ turns the parameter, i.e., a one-character string with the parame-
+ ter as the first character. Otherwise, it returns "~@", "~A",
+ etc., analogous to "^@", "^A", C0 controls.
+
+ X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
+ initializing curses. This implementation permits that, and returns
+ the "~@", etc., values in that case.
+
+ <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
+ pointer.
+
+ The strings returned by <STRONG>unctrl</STRONG> in this implementation are determined at
+ compile time, showing C1 controls from the upper-128 codes with a "~"
+ prefix rather than "^". Other implementations have different conven-
+ tions. For example, they may show both sets of control characters with
+ "^", and strip the parameter to 7 bits. Or they may ignore C1 controls
+ and treat all of the upper-128 codes as printable. This implementation
+ uses 8 bits but does not modify the string to reflect locale. The
+ <STRONG>use_legacy_coding</STRONG> function allows the caller to change the output of
+ <STRONG>unctrl</STRONG>.
+
+ Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
+ of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
+ "meta" keys (codes in the range 128 to 255). Both <STRONG>use_legacy_coding</STRONG>
+ and <STRONG>meta</STRONG> succeed only after curses is initialized. X/Open Curses does
+ not document the treatment of codes 128 to 159. When treating them as
+ "meta" keys (or if <STRONG>keyname</STRONG> is called before initializing curses), this
+ implementation returns strings "M-^@", "M-^A", etc.
+
+ X/Open Curses documents <STRONG>unctrl</STRONG> as declared in <STRONG><unctrl.h></STRONG>, which <STRONG>ncurses</STRONG>
+ does. However, <STRONG>ncurses</STRONG>' <STRONG><curses.h></STRONG> includes <STRONG><unctrl.h></STRONG>, matching the
+ behavior of SVr4 curses. Other implementations may not do that.
projects / ncurses.git / blobdiff