ncurses 6.1 - patch 20191005

[ncurses.git] / man / curs_get_wstr.3x

diff --git a/man/curs_get_wstr.3x b/man/curs_get_wstr.3x
index 22f0e0685af923b5b93a44390545a933bd0c0a18..c869a2126238982d2323b1d150b6a401d18d69ea 100644 (file)
--- a/man/curs_get_wstr.3x
+++ b/man/curs_get_wstr.3x
@@ -1,5 +1,5 @@
 .\"***************************************************************************
-.\" Copyright (c) 2002-2012,2017 Free Software Foundation, Inc.              *
+.\" Copyright (c) 2002-2018,2019 Free Software Foundation, Inc.              *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *
@@ -26,8 +26,12 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: curs_get_wstr.3x,v 1.10 2017/01/07 19:25:15 tom Exp $
+.\" $Id: curs_get_wstr.3x,v 1.18 2019/07/20 19:14:56 tom Exp $
 .TH curs_get_wstr 3X ""
+.de bP
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2
+..
 .na
 .hy 0
 .SH NAME
@@ -67,17 +71,22 @@ The effect of
 is as though a series of calls
 to
 \fBget_wch\fR(3X)
-were made, until a newline, other end-of-line, or end-of-file condition is processed.
-An end-of-file condition is represented by \fBWEOF\fR, as defined in \fB<wchar.h>\fR.
-The newline and end-of-line conditions are represented by the \fB\\n\fR \fBwchar_t\fR value.
+were made, until a newline, other end-of-line,
+or end-of-file condition is processed.
+An end-of-file condition is represented by \fBWEOF\fR,
+as defined in \fB<wchar.h>\fR.
+The newline and end-of-line conditions are represented
+by the \fB\\n\fR \fBwchar_t\fR value.
 In all instances, the end of the string is terminated by a null \fBwchar_t\fR.
 The routine places resulting values in the area pointed to by \fIwstr\fR.
 .PP
-The user's erase and kill characters are interpreted.  If keypad
+The user's erase and kill characters are interpreted.
+If keypad
 mode is on for the window, \fBKEY_LEFT\fR and \fBKEY_BACKSPACE\fR
 are both considered equivalent to the user's kill character.
 .PP
-Characters input are echoed only if \fBecho\fR is currently on.  In that case,
+Characters input are echoed only if \fBecho\fR is currently on.
+In that case,
 backspace is echoed as deletion of the previous character (typically a left
 motion).
 .PP
@@ -161,14 +170,43 @@ or if the window pointer is null.
 .SH PORTABILITY
 These functions are described in The Single Unix Specification, Version 2.
 No error conditions are defined.
-This implementation returns ERR if the window pointer is null,
-or if the lower-level \fBwget_wch\fR call returns an ERR.
+This implementation returns \fBERR\fP if the window pointer is null,
+or if the lower-level \fBwget_wch\fR call returns an \fBERR\fP.
 In the latter case,
-an ERR return without other data is treated as an end-of-file condition,
+an \fBERR\fP return without other data is treated as an end-of-file condition,
 and the returned array contains a \fBWEOF\fR followed by a null \fBwchar_t\fR.
 .PP
-X/Open curses documents these functions to pass an array of \fBwchar_t\fR,
-but all of the vendors implement this using \fBwint_t\fR.
+X/Open curses documented these functions to pass an array of \fBwchar_t\fR
+in 1997, but that was an error because of this part of the description:
+.RS
+.PP
+The effect of \fIget_wstr()\fP is as though a series of calls to
+\fIget_wch()\fP were made, until a newline character, end-of-line character, or
+end-of-file character is processed.
+.RE
+.PP
+The latter function \fIget_wch()\fP can return a negative value,
+while \fBwchar_t\fP is a unsigned type.
+All of the vendors implement this using \fBwint_t\fR, following the standard.
+.PP
+X/Open Curses, Issue 7 (2009) is unclear regarding whether
+the terminating \fInull \fP\fBwchar_t\fP
+value is counted in the length parameter \fIn\fP.
+X/Open Curses, Issue 7 revised the corresponding description
+of \fBwgetnstr\fP to address this issue.
+The unrevised description of \fBwget_nwstr\fP can be interpreted either way.
+This implementation counts the terminator in the length.
+.PP
+X/Open Curses does not specify what happens if the length \fIn\fP is negative.
+.bP
+For analogy with \fBwgetnstr\fP,
+ncurses 6.2 uses a limit (based on \fBLINE_MAX\fP).
+.bP
+Some other implementations (such as Solaris xcurses) do the same,
+while others (PDCurses) do not allow this.
+.bP
+NetBSD 7 curses imitates ncurses 6.1 in this regard,
+treating a \fB\-1\fP as an indefinite number of characters.
 .SH SEE ALSO
 Functions:
 \fBcurses\fR(3X),