- These functions are described in The Single Unix Specifi-
- cation, Version 2. No error conditions are defined. This
- implementation returns ERR if the window pointer is null,
- or if the lower-level <STRONG>wget_wch</STRONG> call returns an ERR. In
- the latter case, an ERR return without other data is
- treated as an end-of-file condition, and the returned ar-
- ray contains a <STRONG>WEOF</STRONG> followed by a null <STRONG>wchar_t</STRONG>.
+ These functions are described in The Single Unix Specification, Version
+ 2. No error conditions are defined.
+
+ This implementation returns <STRONG>ERR</STRONG> if the window pointer is null, or if
+ the lower-level <STRONG>wget_wch</STRONG> call returns an <STRONG>ERR</STRONG>. In the latter case, an
+ <STRONG>ERR</STRONG> return without other data is treated as an end-of-file condition,
+ and the returned array contains a <STRONG>WEOF</STRONG> followed by a null <STRONG>wchar_t</STRONG>.
+
+ X/Open curses documented these functions to pass an array of <STRONG>wchar_t</STRONG> in
+ 1997, but that was an error because of this part of the description:
+
+ The effect of <STRONG>get_wstr</STRONG> is as though a series of calls to <STRONG>get_wch</STRONG>
+ were made, until a newline character, end-of-line character, or
+ end-of-file character is processed.
+
+ The latter function <EM>get</EM><STRONG>_</STRONG><EM>wch</EM> can return a negative value, while <STRONG>wchar_t</STRONG>
+ is a unsigned type. All of the vendors implement this using <STRONG>wint_t</STRONG>,
+ following the standard.
+
+ X/Open Curses, Issue 7 (2009) is unclear regarding whether the termi-
+ nating <EM>null</EM> <STRONG>wchar_t</STRONG> value is counted in the length parameter <EM>n</EM>. X/Open
+ Curses, Issue 7 revised the corresponding description of <STRONG>wgetnstr</STRONG> to
+ address this issue. The unrevised description of <STRONG>wget_nwstr</STRONG> can be in-
+ terpreted either way. This implementation counts the terminator in the
+ length.
+
+ X/Open Curses does not specify what happens if the length <EM>n</EM> is nega-
+ tive.