ncurses 6.0 - patch 20170826

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

diff --git a/man/curs_getch.3x b/man/curs_getch.3x
index 1ef0601388a8fe5f344155b471ee715dbe207b71..b8d6a82b05c242a0e23880bc94fdd4e36aa0a701 100644 (file)
--- a/man/curs_getch.3x
+++ b/man/curs_getch.3x
@@ -1,6 +1,6 @@
 '\" t
 .\"***************************************************************************
-.\" Copyright (c) 1998-2014,2015 Free Software Foundation, Inc.              *
+.\" Copyright (c) 1998-2015,2016 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            *
@@ -27,7 +27,7 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: curs_getch.3x,v 1.44 2015/12/20 01:43:03 tom Exp $
+.\" $Id: curs_getch.3x,v 1.49 2016/10/15 16:44:01 tom Exp $
 .TH curs_getch 3X ""
 .na
 .hy 0
@@ -95,10 +95,17 @@ is read.
 .SS Keypad mode
 .PP
 If \fBkeypad\fR is \fBTRUE\fR, and a function key is pressed, the token for
-that function key is returned instead of the raw characters.
-Possible function
-keys are defined in \fB<curses.h>\fR as macros with values outside the range
-of 8-bit characters whose names begin with \fBKEY_\fR.
+that function key is returned instead of the raw characters:
+.bP
+The predefined function
+keys are listed in \fB<curses.h>\fR as macros with values outside the range
+of 8-bit characters.
+Their names begin with \fBKEY_\fR.
+.bP
+Other (user-defined) function keys which may be defined using \fBdefine_key\fP(3X)
+have no names, but also are expected to have values outside the range of
+8-bit characters.
+.PP
 Thus, a variable
 intended to hold the return value of a function key must be of short size or
 larger.
@@ -111,6 +118,13 @@ time, the character is passed through;
 otherwise, the function key value is returned.
 For this reason, many terminals experience a delay between the time
 a user presses the escape key and the escape is returned to the program.
+.PP
+In \fBncurses\fP, the timer normally expires after the value in \fBESCDELAY\fP (see \fBcurs_variables\fP(3X)).
+If \fBnotimeout\fP is \fBTRUE\fP, the timer does not expire;
+it is an infinite (or very large) value.
+Because function keys usually begin with an escape character,
+the terminal may appear to hang in notimeout mode after pressing the escape key
+until another key is pressed.
 .SS Ungetting characters
 .PP
 The \fBungetch\fR routine places \fIch\fR back onto the input queue to be
@@ -275,7 +289,7 @@ string (see \fBkey_defined\fP(3X)).
 .PP
 .SH RETURN VALUE
 All routines return the integer \fBERR\fR upon failure and an integer value
-other than \fBERR\fR (\fBOK\fR in the case of ungetch()) upon successful
+other than \fBERR\fR (\fBOK\fR in the case of \fBungetch\fP) upon successful
 completion.
 .RS 3
 .TP 5
@@ -286,7 +300,9 @@ if there is no more room in the FIFO.
 \fBwgetch\fP
 returns ERR
 if the window pointer is null, or
-if its timeout expires without having any data.
+if its timeout expires without having any data, or
+if the execution was interrupted by a signal (\fBerrno\fR will be set to
+\fBEINTR\fR).
 .RE
 .PP
 Functions with a "mv" prefix first perform a cursor movement using
@@ -371,8 +387,6 @@ Programmers concerned about portability should be prepared for either of two
 cases: (a) signal receipt does not interrupt \fBgetch\fR; (b) signal receipt
 interrupts \fBgetch\fR and causes it to return ERR with \fBerrno\fR set to
 \fBEINTR\fR.
-Under the \fBncurses\fR implementation, handled signals never
-interrupt \fBgetch\fR.
 .PP
 The \fBhas_key\fR function is unique to \fBncurses\fR.
 We recommend that
@@ -384,6 +398,7 @@ any code using it be conditionalized on the \fBNCURSES_VERSION\fR feature macro.
 \fBcurs_mouse\fR(3X),
 \fBcurs_move\fR(3X),
 \fBcurs_refresh\fR(3X),
+\fBcurs_variables\fR(3X),
 \fBresizeterm\fR(3X).
 .PP
 Comparable functions in the wide-character (ncursesw) library are