ncurses 6.4 - patch 20240420

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

diff --git a/man/curs_getstr.3x b/man/curs_getstr.3x
index d9bed5958976a9ba009629519844dae38261614d..4a49352a146cdf6de9b3b1ca4ce1bee33f1def33 100644 (file)
--- a/man/curs_getstr.3x
+++ b/man/curs_getstr.3x
@@ -1,5 +1,5 @@
 .\"***************************************************************************
 .\"***************************************************************************

-.\" Copyright 2018-2019,2020 Thomas E. Dickey                                *
+.\" Copyright 2018-2023,2024 Thomas E. Dickey                                *

 .\" Copyright 1998-2010,2017 Free Software Foundation, Inc.                  *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" Copyright 1998-2010,2017 Free Software Foundation, Inc.                  *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *


@@ -27,118 +27,174 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"

-.\" $Id: curs_getstr.3x,v 1.29 2020/02/02 23:34:34 tom Exp $
-.TH curs_getstr 3X ""
-.ie \n(.g .ds `` \(lq
-.el       .ds `` ``
-.ie \n(.g .ds '' \(rq
-.el       .ds '' ''
+.\" $Id: curs_getstr.3x,v 1.58 2024/04/20 19:18:18 tom Exp $
+.TH curs_getstr 3X 2024-04-20 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
+.ie \n(.g \{\
+.ds `` \(lq
+.ds '' \(rq
+.\}
+.el \{\
+.ie t .ds `` ``
+.el   .ds `` ""
+.ie t .ds '' ''
+.el   .ds '' ""
+.\}
+.

 .de bP
 .ie n  .IP \(bu 4
 .el    .IP \(bu 2
 ..
 .de bP
 .ie n  .IP \(bu 4
 .el    .IP \(bu 2
 ..

-.na
-.hy 0

 .SH NAME
 .SH NAME

-\fBgetstr\fR,
-\fBgetnstr\fR,
-\fBwgetstr\fR,
-\fBwgetnstr\fR,
-\fBmvgetstr\fR,
-\fBmvgetnstr\fR,
-\fBmvwgetstr\fR,
-\fBmvwgetnstr\fR \- accept character strings from \fBcurses\fR terminal keyboard
-.ad
-.hy
+\fB\%getstr\fP,
+\fB\%getnstr\fP,
+\fB\%wgetstr\fP,
+\fB\%wgetnstr\fP,
+\fB\%mvgetstr\fP,
+\fB\%mvgetnstr\fP,
+\fB\%mvwgetstr\fP,
+\fB\%mvwgetnstr\fP \-
+accept character strings from \fIcurses\fR terminal keyboard

 .SH SYNOPSIS
 .SH SYNOPSIS

-\fB#include <curses.h>\fR
-.sp
-\fBint getstr(char *str);\fR
-.br
-\fBint getnstr(char *str, int n);\fR
-.br
-\fBint wgetstr(WINDOW *win, char *str);\fR
-.br
-\fBint wgetnstr(WINDOW *win, char *str, int n);\fR
-.br
-\fBint mvgetstr(int y, int x, char *str);\fR
-.br
-\fBint mvwgetstr(WINDOW *win, int y, int x, char *str);\fR
-.br
-\fBint mvgetnstr(int y, int x, char *str, int n);\fR
-.br
-\fBint mvwgetnstr(WINDOW *, int y, int x, char *str, int n);\fR
-.br
+.nf
+\fB#include <curses.h>
+.PP
+\fBint getstr(char *\fIstr\fP);
+\fBint getnstr(char *\fIstr\fP, int \fIn\fP);
+\fBint wgetstr(WINDOW *\fIwin\fP, char *\fIstr\fP);
+\fBint wgetnstr(WINDOW *\fIwin\fP, char *\fIstr\fP, int \fIn\fP);
+.PP
+\fBint mvgetstr(int \fIy\fP, int \fIx\fP, char *\fIstr\fP);
+\fBint mvwgetstr(WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, char *\fIstr\fP);
+\fBint mvgetnstr(int \fIy\fP, int \fIx\fP, char *\fIstr\fP, int \fIn\fP);
+\fBint mvwgetnstr(WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, char *\fIstr\fP, int \fIn\fP);
+.fi

 .SH DESCRIPTION
 .SH DESCRIPTION

-The function \fBgetstr\fR is equivalent to a series of calls to \fBgetch\fR,
-until a newline or carriage return is received (the terminating character is
-not included in the returned string).
-.\" X/Open says also until EOf
-.\" X/Open says then an EOS is added to the result
-.\" X/Open doesn't mention n<0
-The resulting value is placed in the
-area pointed to by the character pointer \fIstr\fR,
-followed by a NUL.
-.PP
-\fBwgetnstr\fR reads at most \fIn\fR 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 \fBgetnstr\fR function reads
-from the \fIstdscr\fR default window.
-.PP
-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.
+The function
+\fBwgetnstr\fP
+is equivalent to a series of calls to
+\fBwgetch\fP(3X),
+until a newline or carriage return terminates the series:
+.bP
+The terminating character is not included in the returned string.
+.bP
+In all instances, the end of the string is terminated
+by a NUL.
+.bP
+The function stores the result in the area pointed to
+by the \fIstr\fP parameter.
+.bP
+The function reads at most \fIn\fP characters,
+thus preventing a possible overflow of the input buffer.
+.IP
+Any attempt to enter more characters
+(other than the terminating newline or carriage return)
+causes a beep.
+.IP
+Function keys also cause a beep and are ignored.
+.PP
+The user's \fIerase\fP and \fIkill\fP characters are interpreted:
+.bP
+The \fIerase\fP character (e.g., \fB^H\fP) erases the character
+at the end of the buffer, moving the cursor to the left.
+.IP
+If \fIkeypad\fP mode is on for the window,
+\fBKEY_LEFT\fP and \fBKEY_BACKSPACE\fP
+are both considered equivalent to the user's \fIerase\fP character.
+.bP
+The \fIkill\fP character (e.g., \fB^U\fP) erases the entire buffer,
+leaving the cursor at the beginning of the buffer.
+.PP
+Characters input are echoed only if \fBecho\fP is currently on.

 In that case,
 In that case,

-backspace is echoed as deletion of the previous character (typically a left
-motion).
+backspace is echoed as deletion of the previous character
+(typically a left motion).
+.PP
+The
+\fBgetnstr\fP,
+\fBmvgetnstr\fP,
+\fBmvwgetnstr\fP, and
+\fBwgetnstr\fP
+functions are identical
+to the
+\fBgetstr\fP,
+\fBmvgetstr\fP,
+\fBmvwgetstr\fP, and
+\fBwgetstr\fP
+functions, respectively,
+except that the
+\fB*n*\fP
+versions read at most
+\fIn\fP
+characters, letting the application prevent overflow of the
+input buffer.

 .SH RETURN VALUE
 .SH RETURN VALUE

-All routines return the integer \fBERR\fR upon failure and an \fBOK\fR (SVr4
-specifies only \*(``an integer value other than \fBERR\fR\*('') upon successful
-completion.
+All of these functions return the integer \fBOK\fP upon successful completion.
+(SVr4 specifies only \*(``an integer value other than \fBERR\fP\*('')
+If unsuccessful, they return \fBERR\fP.

 .PP
 X/Open defines no error conditions.
 .PP
 In this implementation,
 these functions return an error
 .PP
 X/Open defines no error conditions.
 .PP
 In this implementation,
 these functions return an error

-if the window pointer is null, or
-if its timeout expires without having any data.
+.bP
+if the window pointer is null,
+.bP
+if its timeout expires without having any data, or
+.bP
+if the associated call to
+\fBwgetch\fP
+failed.

 .PP
 This implementation provides an extension as well.
 If a \fBSIGWINCH\fP interrupts the function, it will return \fBKEY_RESIZE\fP
 rather than \fBOK\fP or \fBERR\fP.
 .PP
 .PP
 This implementation provides an extension as well.
 If a \fBSIGWINCH\fP interrupts the function, it will return \fBKEY_RESIZE\fP
 rather than \fBOK\fP or \fBERR\fP.
 .PP

-Functions with a \*(``mv\*('' prefix first perform a cursor movement using
-\fBwmove\fP, and return an error if the position is outside the window,
-or if the window pointer is null.
+Functions prefixed with \*(``mv\*('' first perform cursor movement and
+fail if the position
+.RI ( y ,
+.IR x )
+is outside the window boundaries.

 .SH NOTES
 .SH NOTES

-Note that \fBgetstr\fR, \fBmvgetstr\fR, and \fBmvwgetstr\fR may be macros.
+Any of these functions other than
+\fBwgetnstr\fP
+may be macros.
+.PP
+Using
+\fBgetstr\fP,
+\fBmvgetstr\fP,
+\fBmvwgetstr\fP, or
+\fBwgetstr\fP
+to read a line that
+overflows the array pointed to by
+\fBstr\fP
+causes undefined
+results.
+The use of
+\fBgetnstr\fP,
+\fBmvgetnstr\fP,
+\fBmvwgetnstr\fP, or
+\fBwgetnstr\fP,
+respectively, is recommended.

 .SH PORTABILITY
 .SH PORTABILITY

-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.
+These functions are described in The Single Unix Specification, Version 2.
+No error conditions are defined.
+.PP

 This implementation returns \fBERR\fP if the window pointer is null,
 This implementation returns \fBERR\fP if the window pointer is null,

-or if the lower-level \fBwgetch\fR(3X) call returns an \fBERR\fP.
+or if the lower-level \fBwgetch\fP(3X) call returns an \fBERR\fP.

 .PP
 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,
 .PP
 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,

-\fIetc\fR.) are \*(``interpreted\*('',
+\fIetc\fP.) are \*(``interpreted\*('',

 without 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).
 .PP
 without 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).
 .PP

-The functions \fBgetnstr\fR, \fBmvgetnstr\fR, and \fBmvwgetnstr\fR were
+The functions \fBgetnstr\fP, \fBmvgetnstr\fP, and \fBmvwgetnstr\fP were

 present but not documented in SVr4.
 .PP
 X/Open Curses, Issue 5 (2007) stated that these functions
 present but not documented in SVr4.
 .PP
 X/Open Curses, Issue 5 (2007) stated that these functions


@@ -147,9 +203,9 @@ 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 \fIn\fP\-1 bytes\*(''
 to allow for the terminating NUL.
 X/Open Curses, Issue 7 (2009) changed that to say they
 \*(``read at most \fIn\fP\-1 bytes\*(''
 to allow for the terminating NUL.

-As of 2018, some implementations do, some do not count it:
+As of 2018, some implementations count it, some do not:

 .bP
 .bP

-ncurses 6.1 and PDCurses do not count the NUL in the given limit, while
+\fI\%ncurses\fP 6.1 and PDCurses do not count the NUL in the given limit, while

 .bP
 Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
 .bP
 .bP
 Solaris SVr4 and NetBSD curses count the NUL as part of the limit.
 .bP


@@ -177,17 +233,69 @@ that it is greater than zero.
 .IP
 A comment in NetBSD's source code states that this is specified in SUSv2.
 .bP
 .IP
 A comment in NetBSD's source code states that this is specified in SUSv2.
 .bP

-ncurses (before 6.2) assumes no particular limit for the result
+\fI\%ncurses\fP (before 6.2) assumes no particular limit for the result

 from \fBwgetstr\fP, and treats the \fIn\fP parameter of \fBwgetnstr\fP
 like SVr4 curses.
 .bP
 from \fBwgetstr\fP, and treats the \fIn\fP parameter of \fBwgetnstr\fP
 like SVr4 curses.
 .bP

-ncurses 6.2 uses \fBLINE_MAX\fP,
+\fI\%ncurses\fP 6.2 uses \fBLINE_MAX\fP,

 or a larger (system-dependent) value
 which the \fBsysconf\fP function may provide.
 If neither \fBLINE_MAX\fP or \fBsysconf\fP is available,
 or a larger (system-dependent) value
 which the \fBsysconf\fP function may provide.
 If neither \fBLINE_MAX\fP or \fBsysconf\fP is available,

-ncurses uses the POSIX value for \fBLINE_MAX\fP (a 2048 byte limit).
+\fI\%ncurses\fP uses the POSIX value for \fBLINE_MAX\fP (a 2048 byte limit).

 In either case, it reserves a byte for the terminating NUL.
 In either case, it reserves a byte for the terminating NUL.

+.PP
+Although \fBgetnstr\fP is equivalent to a series of calls to \fBgetch\fP,
+it also makes changes to the curses modes to allow simple editing of
+the input buffer:
+.bP
+\fBgetnstr\fP saves the current value of the \fBnl\fP, \fBecho\fP,
+\fBraw\fP and \fBcbreak\fP modes, and sets
+\fBnl\fP,
+\fBnoecho\fP,
+\fBnoraw\fP, and
+\fBcbreak\fP.
+.IP
+\fBgetnstr\fP handles the echoing of characters,
+rather than relying on the caller to set an appropriate mode.
+.bP
+It also obtains the \fIerase\fP and \fIkill\fP characters
+from \fBerasechar\fP and \fBkillchar\fP, respectively.
+.bP
+On return, \fBgetnstr\fP restores the modes to their previous values.
+.PP
+Other implementations differ in their treatment of special characters:
+.bP
+While they may set the \fIecho\fP mode,
+other implementations do not modify the \fIraw\fP mode,
+They may take the \fIcbreak\fP
+mode set by the caller into account when deciding whether to handle
+echoing within \fBgetnstr\fP or as a side-effect of the \fBgetch\fP calls.
+.bP
+The original \fI\%ncurses\fP
+(as \fIpcurses\fP in 1986)
+set \fBnoraw\fP and \fBcbreak\fP when accepting input for \fBgetnstr\fP.
+That may have been done to make function- and cursor-keys work;
+it is not necessary with \fI\%ncurses\fP.
+.IP
+Since 1995,
+\fI\%ncurses\fP has provided signal handlers for INTR and QUIT
+(e.g., \fB^C\fP or \fB^\e\fP).
+With the \fBnoraw\fP and \fBcbreak\fP settings,
+those may catch a signal and stop the program,
+where other implementations allow one to enter those characters in the buffer.
+.bP
+Starting in 2021
+(\fI\%ncurses\fP 6.3),
+\fBgetnstr\fP sets \fBraw\fP,
+rather than \fBnoraw\fP and \fBcbreak\fP for better compatibility with
+SVr4-curses, e.g., allowing one to enter a \fB^C\fP into the buffer.

 .SH SEE ALSO
 .SH SEE ALSO

-\fBcurses\fR(3X),
-\fBcurs_getch\fR(3X),
-\fBcurs_variables\fR(3X).
+\fB\%curs_get_wstr\fP(3X) describes comparable functions of the
+.I \%ncurses
+library in its wide-character configuration
+.RI ( \%ncursesw ).
+.PP
+\fB\%curses\fP(3X),
+\fB\%curs_getch\fP(3X),
+\fB\%curs_termattrs\fP(3X),
+\fB\%curs_variables\fP(3X)