HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)

curses_intro(3X) curses_intro(3X)

(X/Open CURSES)

The complete set of key codes for keypad keys that Curses can process is speciﬁed by the constants

deﬁned in <curses.h> whose names begin with ‘‘KEY_’’. Each terminal type described in the ter-

minfo database may support some or all of these key codes. The terminfo database speciﬁes the

sequence of input characters from the terminal type that correspond to each key code (see Keypad in ter-

minfo(4)).

The Curses implementation cannot translate keypad keys on terminals where pressing the keys does not

transmit a unique sequence.

When translation is enabled and a character that could be the beginning of a function key (such as

escape) is received, Curses notes the time and begins accumulating characters. If Curses receives addi-

tional characters that represent the pressing of a keypad key, within an unspeciﬁed interval from the

time the ﬁrst character was received, then Curses converts this input to a key code for presentation to the

application. If such characters are not received during this interval, translation of this input does not

occur and the individual characters are presented to the application separately. (Because Curses waits

for this interval to accumulate a key code, many terminals experience a delay between the time a user

presses the escape key and the time the escape is returned to the application.)

In addition, No Timeout Mode provides that in any case where Curses has received part of a function key

sequence, it waits indeﬁnitely for the complete key sequence. The ‘‘unspeciﬁed interval’’ in the previous

paragraph becomes inﬁnite in No Timeout Mode. No Timeout Mode allows the use of function keys over

slow communication lines. No Timeout Mode lets the user type the individual characters of a function

key sequence, but also delays application response when the user types a character (not a function key)

that begins a function key sequence. For this reason, in No Timeout Mode many terminals will appear to

hang between the time a user presses the escape key and the time another key is pressed. No Timeout

Mode is switchable by calling

notimeout().

If any special characters (see Special Characters in curses_intro) are deﬁned or redeﬁned to be characters

that are members of a function key sequence, then Curses will be unable to recognise and translate those

function keys.

Several of the modes discussed below are described in terms of availability of input. If keypad translation

is enabled, then input is not available once Curses has begun receiving a keypad sequence until the

sequence is completely received or the interval has elapsed.

Input Mode

The X/Open System Interface Deﬁnitions, Issue 4, Version 2 speciﬁcation (Special Characters ) deﬁnes

ﬂow-control characters, the interrupt character, the erase character, and the kill character. Four

mutually-exclusive Curses modes let the application control the effect of these input characters:

Section 3−−176 Hewlett-Packard Company − 10 − HP-UX 11i Version 2: September 2004