* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
- * @Id: curs_getstr.3x,v 1.40 2023/07/01 15:43:20 tom Exp @
- * X/Open says also until EOf
- * X/Open says then an EOS is added to the result
- * X/Open doesn't mention n<0
+ * @Id: curs_getstr.3x,v 1.41 2023/07/29 16:32:52 tom Exp @
-->
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-<H1 class="no-header">curs_getstr 3x 2023-07-01 ncurses 6.4 Library calls</H1>
+<H1 class="no-header">curs_getstr 3x 2023-07-29 ncurses 6.4 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- The function <STRONG>getstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, until
- a newline or carriage return is received (the terminating character is
- not included in the returned string). The resulting value is placed in
- the area pointed to by the character pointer <EM>str</EM>, followed by a NUL.
+ The function <STRONG>wgetnstr</STRONG> is equivalent to a series of calls to <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>,
+ until a newline or carriage return terminates the series:
- The <STRONG>getnstr</STRONG> function reads from the <EM>stdscr</EM> default window. The other
- functions, such as <STRONG>wgetnstr</STRONG>, read from the window given as a parameter.
+ <STRONG>o</STRONG> The terminating character is not included in the returned string.
- <STRONG>getnstr</STRONG> reads at most <EM>n</EM> characters, thus preventing a possible overflow
- of the input buffer. Any attempt to enter more characters (other than
- the terminating newline or carriage return) causes a beep. Function
- keys also cause a beep and are ignored.
+ <STRONG>o</STRONG> In all instances, the end of the string is terminated by a NUL.
+
+ <STRONG>o</STRONG> The function stores the result in the area pointed to by the <EM>str</EM>
+ parameter.
+
+ <STRONG>o</STRONG> The function reads at most <EM>n</EM> characters, thus preventing a possible
+ overflow of the input buffer.
+
+ Any attempt to enter more characters (other than the terminating
+ newline or carriage return) causes a beep.
+
+ Function keys also cause a beep and are ignored.
The user's <EM>erase</EM> and <EM>kill</EM> characters are interpreted:
- <STRONG>o</STRONG> The <EM>erase</EM> character (e.g., <STRONG>^H</STRONG>) erases the character at the end of
+ <STRONG>o</STRONG> The <EM>erase</EM> character (e.g., <STRONG>^H</STRONG>) erases the character at the end of
the buffer, moving the cursor to the left.
If <EM>keypad</EM> mode is on for the window, <STRONG>KEY_LEFT</STRONG> and <STRONG>KEY_BACKSPACE</STRONG> are
- both considered equivalent to the user's erase character.
+ both considered equivalent to the user's <EM>erase</EM> character.
<STRONG>o</STRONG> The <EM>kill</EM> character (e.g., <STRONG>^U</STRONG>) erases the entire buffer, leaving the
cursor at the beginning of the buffer.
- Characters input are echoed only if <STRONG>echo</STRONG> is currently on. In that
- case, backspace is echoed as deletion of the previous character (typi-
+ Characters input are echoed only if <STRONG>echo</STRONG> is currently on. In that
+ case, backspace is echoed as deletion of the previous character (typi-
cally a left motion).
+ The <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetnstr</STRONG>, and <STRONG>wgetnstr</STRONG> functions are identi-
+ cal to the <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvwgetstr</STRONG>, and <STRONG>wgetstr</STRONG> functions, respec-
+ tively, except that the <STRONG>*n*</STRONG> versions read at most <EM>n</EM> characters, letting
+ the application prevent overflow of the input buffer.
+
+
+</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+ Any of these functions other than <STRONG>wgetnstr</STRONG> may be macros.
+
+ Using <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvwgetstr</STRONG>, or <STRONG>wgetstr</STRONG> to read a line that over-
+ flows the array pointed to by <STRONG>str</STRONG> causes undefined results. The use of
+ <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetnstr</STRONG>, or <STRONG>wgetnstr</STRONG>, respectively, is recom-
+ mended.
+
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- All routines return the integer <STRONG>ERR</STRONG> upon failure and an <STRONG>OK</STRONG> (SVr4 speci-
- fies only "an integer value other than <STRONG>ERR</STRONG>") upon successful comple-
- tion.
+ All of these functions return the integer <STRONG>OK</STRONG> upon successful comple-
+ tion. (SVr4 specifies only "an integer value other than <STRONG>ERR</STRONG>") If un-
+ successful, they return <STRONG>ERR</STRONG>.
X/Open defines no error conditions.
- In this implementation, these functions return an error if the window
- pointer is null, or if its timeout expires without having any data.
+ In this implementation, these functions return an error
+
+ <STRONG>o</STRONG> if the window pointer is null, or
+
+ <STRONG>o</STRONG> if its timeout expires without having any data.
+
+ <STRONG>o</STRONG> if the associated call to <STRONG>wgetch</STRONG> failed.
This implementation provides an extension as well. If a <STRONG>SIGWINCH</STRONG> in-
terrupts the function, it will return <STRONG>KEY_RESIZE</STRONG> rather than <STRONG>OK</STRONG> or <STRONG>ERR</STRONG>.
the window pointer is null.
-</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- Note that <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, and <STRONG>mvwgetstr</STRONG> may be macros.
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ 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><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> call returns an <STRONG>ERR</STRONG>.
-</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- These functions are described in the XSI Curses standard, Issue 4.
- They read single-byte characters only. The standard does not define
- any error conditions. This implementation returns <STRONG>ERR</STRONG> if the window
- pointer is null, or if the lower-level <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> call returns an <STRONG>ERR</STRONG>.
-
- SVr3 and early SVr4 curses implementations did not reject function
- keys; the SVr4.0 documentation claimed that "special keys" (such as
- function keys, "home" key, "clear" key, <EM>etc</EM>.) are "interpreted", with-
- out giving details. It lied. In fact, the "character" value appended
- to the string by those implementations was predictable but not useful
+ SVr3 and early SVr4 curses implementations did not reject function
+ keys; the SVr4.0 documentation claimed that "special keys" (such as
+ function keys, "home" key, "clear" key, <EM>etc</EM>.) are "interpreted", with-
+ out giving details. It lied. In fact, the "character" value appended
+ to the string by those implementations was predictable but not useful
(being, in fact, the low-order eight bits of the key's KEY_ value).
- The functions <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, and <STRONG>mvwgetnstr</STRONG> were present but not
+ The functions <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, and <STRONG>mvwgetnstr</STRONG> were present but not
documented in SVr4.
X/Open Curses, Issue 5 (2007) stated that these functions "read at most
- <EM>n</EM> bytes" but did not state whether the terminating NUL is counted in
- that limit. X/Open Curses, Issue 7 (2009) changed that to say they
+ <EM>n</EM> bytes" but did not state whether the terminating NUL is counted in
+ that limit. X/Open Curses, Issue 7 (2009) changed that to say they
"read at most <EM>n</EM>-1 bytes" to allow for the terminating NUL. As of 2018,
- some implementations do, some do not count it:
+ some implementations count it, some do not:
- <STRONG>o</STRONG> ncurses 6.1 and PDCurses do not count the NUL in the given limit,
+ <STRONG>o</STRONG> ncurses 6.1 and PDCurses do not count the NUL in the given limit,
while
<STRONG>o</STRONG> Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
- <STRONG>o</STRONG> Solaris xcurses provides both: its wide-character <STRONG>wget_nstr</STRONG> re-
+ <STRONG>o</STRONG> Solaris xcurses provides both: its wide-character <STRONG>wget_nstr</STRONG> re-
serves a NUL, but its <STRONG>wgetnstr</STRONG> does not count the NUL consistently.
In SVr4 curses, a negative value of <EM>n</EM> tells <STRONG>wgetnstr</STRONG> to assume that the
- caller's buffer is large enough to hold the result, i.e., to act like
- <STRONG>wgetstr</STRONG>. X/Open Curses does not mention this (or anything related to
- negative or zero values of <EM>n</EM>), however most implementations use the
+ caller's buffer is large enough to hold the result, i.e., to act like
+ <STRONG>wgetstr</STRONG>. X/Open Curses does not mention this (or anything related to
+ negative or zero values of <EM>n</EM>), however most implementations use the
feature, with different limits:
- <STRONG>o</STRONG> Solaris SVr4 curses and PDCurses limit the result to 255 bytes.
+ <STRONG>o</STRONG> Solaris SVr4 curses and PDCurses limit the result to 255 bytes.
Other Unix systems than Solaris are likely to use the same limit.
<STRONG>o</STRONG> Solaris xcurses limits the result to <STRONG>LINE_MAX</STRONG> bytes.
- <STRONG>o</STRONG> NetBSD 7 assumes no particular limit for the result from <STRONG>wgetstr</STRONG>.
- However, it limits the <STRONG>wgetnstr</STRONG> parameter <EM>n</EM> to ensure that it is
+ <STRONG>o</STRONG> NetBSD 7 assumes no particular limit for the result from <STRONG>wgetstr</STRONG>.
+ However, it limits the <STRONG>wgetnstr</STRONG> parameter <EM>n</EM> to ensure that it is
greater than zero.
- A comment in NetBSD's source code states that this is specified in
+ A comment in NetBSD's source code states that this is specified in
SUSv2.
- <STRONG>o</STRONG> ncurses (before 6.2) assumes no particular limit for the result
- from <STRONG>wgetstr</STRONG>, and treats the <EM>n</EM> parameter of <STRONG>wgetnstr</STRONG> like SVr4
+ <STRONG>o</STRONG> ncurses (before 6.2) assumes no particular limit for the result
+ from <STRONG>wgetstr</STRONG>, and treats the <EM>n</EM> parameter of <STRONG>wgetnstr</STRONG> like SVr4
curses.
- <STRONG>o</STRONG> ncurses 6.2 uses <STRONG>LINE_MAX</STRONG>, or a larger (system-dependent) value
- which the <STRONG>sysconf</STRONG> function may provide. If neither <STRONG>LINE_MAX</STRONG> or
- <STRONG>sysconf</STRONG> is available, ncurses uses the POSIX value for <STRONG>LINE_MAX</STRONG> (a
- 2048 byte limit). In either case, it reserves a byte for the ter-
+ <STRONG>o</STRONG> ncurses 6.2 uses <STRONG>LINE_MAX</STRONG>, or a larger (system-dependent) value
+ which the <STRONG>sysconf</STRONG> function may provide. If neither <STRONG>LINE_MAX</STRONG> or
+ <STRONG>sysconf</STRONG> is available, ncurses uses the POSIX value for <STRONG>LINE_MAX</STRONG> (a
+ 2048 byte limit). In either case, it reserves a byte for the ter-
minating NUL.
- Although <STRONG>getnstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, it also
- makes changes to the curses modes to allow simple editing of the input
+ Although <STRONG>getnstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, it also
+ makes changes to the curses modes to allow simple editing of the input
buffer:
- <STRONG>o</STRONG> <STRONG>getnstr</STRONG> saves the current value of the <STRONG>nl</STRONG>, <STRONG>echo</STRONG>, <STRONG>raw</STRONG> and <STRONG>cbreak</STRONG>
+ <STRONG>o</STRONG> <STRONG>getnstr</STRONG> saves the current value of the <STRONG>nl</STRONG>, <STRONG>echo</STRONG>, <STRONG>raw</STRONG> and <STRONG>cbreak</STRONG>
modes, and sets <STRONG>nl</STRONG>, <STRONG>noecho</STRONG>, <STRONG>noraw</STRONG>, and <STRONG>cbreak</STRONG>.
- <STRONG>getnstr</STRONG> handles the echoing of characters, rather than relying on
+ <STRONG>getnstr</STRONG> handles the echoing of characters, rather than relying on
the caller to set an appropriate mode.
- <STRONG>o</STRONG> It also obtains the <EM>erase</EM> and <EM>kill</EM> characters from <STRONG>erasechar</STRONG> and
+ <STRONG>o</STRONG> It also obtains the <EM>erase</EM> and <EM>kill</EM> characters from <STRONG>erasechar</STRONG> and
<STRONG>killchar</STRONG>, respectively.
<STRONG>o</STRONG> On return, <STRONG>getnstr</STRONG> restores the modes to their previous values.
Other implementations differ in their treatment of special characters:
<STRONG>o</STRONG> While they may set the <EM>echo</EM> mode, other implementations do not mod-
- ify the <EM>raw</EM> mode, They may take the <EM>cbreak</EM> mode set by the caller
+ ify the <EM>raw</EM> mode, They may take the <EM>cbreak</EM> mode set by the caller
into account when deciding whether to handle echoing within <STRONG>getnstr</STRONG>
or as a side-effect of the <STRONG>getch</STRONG> calls.
accepting input for <STRONG>getnstr</STRONG>. That may have been done to make func-
tion- and cursor-keys work; it is not necessary with ncurses.
- Since 1995, ncurses has provided signal handlers for INTR and QUIT
- (e.g., <STRONG>^C</STRONG> or <STRONG>^\</STRONG>). With the <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> settings, those may
- catch a signal and stop the program, where other implementations
+ Since 1995, ncurses has provided signal handlers for INTR and QUIT
+ (e.g., <STRONG>^C</STRONG> or <STRONG>^\</STRONG>). With the <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> settings, those may
+ catch a signal and stop the program, where other implementations
allow one to enter those characters in the buffer.
<STRONG>o</STRONG> Starting in 2021 (ncurses 6.3), <STRONG>getnstr</STRONG> sets <STRONG>raw</STRONG>, rather than <STRONG>noraw</STRONG>
- and <STRONG>cbreak</STRONG> for better compatibility with SVr4-curses, e.g., allow-
+ and <STRONG>cbreak</STRONG> for better compatibility with SVr4-curses, e.g., allow-
ing one to enter a <STRONG>^C</STRONG> into the buffer.
-ncurses 6.4 2023-07-
01 <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>
+ncurses 6.4 2023-07-
29 <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
-<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
+<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
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