.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_instr.3x,v 1.51 2024/04/20 21:24:19 tom Exp $
-.TH curs_instr 3X 2024-04-20 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
+.\" $Id: curs_instr.3x,v 1.57 2024/06/08 20:47:39 tom Exp $
+.TH curs_instr 3X 2024-06-08 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
.nf
\fB#include <curses.h>
.PP
-\fBint instr(char *\fIstr\fP);
-\fBint innstr(char *\fIstr\fP, int \fIn\fP);
-\fBint winstr(WINDOW *\fIwin\fP, char *\fIstr\fP);
-\fBint winnstr(WINDOW *\fIwin\fP, char *\fIstr\fP, int \fIn\fP);
+\fBint instr(char *\ \fIstr\fP);
+\fBint winstr(WINDOW *\ \fIwin\fP, char *\ \fIstr\fP);
+\fBint mvinstr(int \fIy\fP, int \fIx\fP, char *\ \fIstr\fP);
+\fBint mvwinstr(WINDOW *\ \fIwin\fP, int \fIy\fP, int \fIx\fP, char *\ \fIstr\fP);
.PP
-\fBint mvinstr(int \fIy\fP, int \fIx\fP, char *\fIstr\fP);
-\fBint mvinnstr(int \fIy\fP, int \fIx\fP, char *\fIstr\fP, int \fIn\fP);
-\fBint mvwinstr(WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, char *\fIstr\fP);
-\fBint mvwinnstr(WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, char *\fIstr\fP, int \fIn\fP);
+\fBint innstr(char *\ \fIstr\fP, int \fIn\fP);
+\fBint winnstr(WINDOW *\ \fIwin\fP, char *\ \fIstr\fP, int \fIn\fP);
+\fBint mvinnstr(int \fIy\fP, int \fIx\fP, char *\ \fIstr\fP, int \fIn\fP);
+\fBint mvwinnstr(WINDOW *\ \fIwin\fP, int \fIy\fP, int \fIx\fP, char *\ \fIstr\fP, int \fIn\fP);
.fi
.SH DESCRIPTION
-These routines return a string of characters in \fIstr\fP,
-starting at the current cursor position in the named window.
-Attributes are stripped from the characters.
-.PP
-The four functions with \fIn\fP as the last argument return
-a leading substring at most \fIn\fP characters long
-(exclusive of the trailing NUL).
-Transfer stops at the end of the current line, or when \fIn\fP characters have
-been stored at the location referenced by \fIstr\fP.
+.B \%winstr
+extracts a string from a
+.I curses
+window
+.IR win ","
+starting at the cursor and stopping at the end of the line,
+and stores it in
+.IR str ","
+terminating it with a null character
+and
+omitting any attributes and color pair identifier
+that
+.I curses
+associates with each character.
+.B \%winnstr
+does the same,
+but copies at most
+.I n
+characters from
+.IR win "."
+An
+.I n
+of
+.B \-1
+implies no limit;
+.B \%winnstr
+then works like
+.BR \%winstr "."
+\fB\%ncurses\fP(3X) describes the variants of these functions.
.SH RETURN VALUE
-All of the functions return \fBERR\fP upon failure,
-or the number of characters actually read into the string.
+These functions return the count of characters copied from
+.I win
+to
+.IR str ","
+or
+.B ERR
+upon failure.
.PP
-X/Open Curses defines no error conditions.
-This implementation returns an error
+In
+.IR \%ncurses ","
+they return
+.B ERR
+if
.bP
-if the \fIwin\fP parameter is null or
+.I win
+is
+.B NULL
+or
.bP
-if the \fIchstr\fP parameter is null.
+.I str
+is
+.BR NULL "."
.PP
Functions prefixed with \*(``mv\*('' first perform cursor movement and
fail if the position
.IR x )
is outside the window boundaries.
.SH NOTES
-All routines except \fBwinnstr\fP may be macros.
+All of these functions except
+.B \%winnstr
+may be implemented as macros.
.PP
Reading a line that overflows the array pointed to by
-\fIstr\fP
+.I str
with
-\fBinstr\fP,
-\fBmvinstr\fP,
-\fBmvwinstr\fP
+.BR \%instr ","
+.BR \%winstr ","
+.BR \%mvinstr ","
or
-\fBwinstr\fP
+.B \%mvwinstr
causes undefined results.
-Therefore, the use of
-\fBinnstr\fP,
-\fBmvinnstr\fP,
-\fBmvwinnstr\fP, or
-\fBwinnstr\fP
-is recommended.
+Use of
+.BR \%innstr ","
+.BR \%winnstr ","
+.BR \%mvinnstr ","
+and
+.B \%mvwinnstr
+is recommended instead.
+.SH EXTENSIONS
+.BR \%innstr ","
+.BR \%winnstr ","
+.BR \%mvinnstr ","
+and
+.BR \%mvwinnstr "'s"
+treatment of
+.B \-1
+as a valid value of
+.I n
+is an
+.I \%ncurses
+extension.
.SH PORTABILITY
-SVr4 does not
-document whether a length limit includes or excludes the trailing NUL.
+Applications employing
+.I \%ncurses
+extensions should condition their use on the visibility of the
+.B \%NCURSES_VERSION
+preprocessor macro.
.PP
-The \fI\%ncurses\fP library extends the X/Open Curses description by allowing a
-negative value for \fIn\fP.
-In this case, the functions return the string ending at the right margin.
+X/Open Curses,
+Issue 4 describes these functions.
+It specifies no error conditions for them.
+.PP
+X/Open Curses Issues 4 and 7 both state that
+.BR \%instr ","
+.BR \%winstr ","
+.BR \%mvinstr ","
+and
+.B \%mvwinstr
+return
+.B OK
+rather than a character count.
+This is likely an erratum.
+.bP
+SVr3.1 and SVr4 implemented
+.B \%winstr
+as a wrapper around
+.BR \%winnstr ","
+returning the latter's return value.
+X/Open Curses's specification thus may have been an editorial solecism
+copied from System\ V's documentation
+(see below)
+by X/Open,
+rather than an intentional change.
+.bP
+.I \%ncurses
+retains compatibility with System\ V
+.I curses
+behavior.
+.PP
+SVr4 documents no return values apart from
+.B OK
+and
+.B ERR
+for any of these functions.
+SVr4 does not
+document whether
+.I n
+counts the null terminator that these functions write to
+.IR str "."
+.SH HISTORY
+SVr3.1 (1987)
+introduced these functions.
.SH SEE ALSO
-\fB\%curs_ins_wstr\fP(3X) describes comparable functions of the
+\fB\%curs_inwstr\fP(3X) describes comparable functions of the
.I \%ncurses
library in its wide-character configuration
-.RI ( \%ncursesw ).
+.RI \%( ncursesw ).
.PP
\fB\%curses\fP(3X),
\fB\%curs_inch\fP(3X),
projects / ncurses.git / blobdiff