NAME
ggeettcchh, wwggeettcchh, mmvvggeettcchh, mmvvwwggeettcchh, uunnggeettcchh, hhaasskkeeyy - get (or push back)
characters from ccuurrsseess terminal keyboardSYNOPSIS
##iinncclluuddee <
iinntt ggeettcchh((vvooiidd));; iinntt wwggeettcchh((WWIINNDDOOWW **wwiinn));; iinntt mmvvggeettcchh((iinntt yy,, iinntt xx));; iinntt mmvvwwggeettcchh((WWIINNDDOOWW **wwiinn,, iinntt yy,, iinntt xx));; iinntt uunnggeettcchh((iinntt cchh));; iinntt hhaasskkeeyy((iinntt cchh));;> DESCRIPTION
The ggeettcchh, wwggeettcchh, mmvvggeettcchh and mmvvwwggeettcchh, routines read a character fromthe window. In no-delay mode, if no input is waiting, the value EERRRR is
returned. In delay mode, the program waits until the system passes text through to the program. Depending on the setting of ccbbrreeaakk, this is after one character (cbreak mode), or after the first newline(nocbreak mode). In half-delay mode, the program waits until a charac-
ter is typed or the specified timeout has been reached. Unless nnooeecchhoo has been set, then the character will also be echoed intothe designated window according to the following rules: If the charac-
ter is the current erase character, left arrow, or backspace, the cur-
sor is moved one space to the left and that screen position is erased as if ddeellcchh had been called. If the character value is any other KKEEYY define, the user is alerted with a bbeeeepp call. Otherwise the character is simply output to the screen. If the window is not a pad, and it has been moved or modified since the last call to wwrreeffrreesshh, wwrreeffrreesshh will be called before another character is read. If kkeeyyppaadd is TTRRUUEE, and a function key is pressed, the token for thatfunction key is returned instead of the raw characters. Possible func-
tion keys are defined in <> as macros with values outside the range of 8-bit characters whose names begin with KKEEYY. Thus, a variable
intended to hold the return value of a function key must be of short size or larger.When a character that could be the beginning of a function key is re-
ceived (which, on modern terminals, means an escape character), ccuurrsseess sets a timer. If the remainder of the sequence does not come in within the designated time, the character is passed through; otherwise, thefunction key value is returned. For this reason, many terminals expe-
rience a delay between the time a user presses the escape key and the escape is returned to the program. The uunnggeettcchh routine places ch back onto the input queue to be returnedby the next call to wwggeettcchh. There is just one input queue for all win-
dows. FFuunnccttiioonn KKeeyyss The following function keys, defined in <>, might be returned by ggeettcchh if kkeeyyppaadd has been enabled. Note that not all of these are necessarily supported on any particular terminal. Name Key name KEYBREAK Break key KEYDOWN The four arrow keys ... KEYUP KEYLEFT KEYRIGHT KEYHOME Home key (upward+left arrow) KEYBACKSPACE Backspace KEYF0 Function keys; space for 64 keys is reserved. KEYF(n) For 0 <= n <= 63 KEYDL Delete line KEYIL Insert line KEYDC Delete character KEYIC Insert char or enter insert mode KEYEIC Exit insert char mode KEYCLEAR Clear screen KEYEOS Clear to end of screen KEYEOL Clear to end of line KEYSF Scroll 1 line forward KEYSR Scroll 1 line backward (reverse) KEYNPAGE Next page KEYPPAGE Previous page KEYSTAB Set tab KEYCTAB Clear tab KEYCATAB Clear all tabs KEYENTER Enter or send KEYSRESET Soft (partial) reset KEYRESET Reset or hard reset KEYPRINT Print or copy KEYLL Home down or bottom (lower left) KEYA1 Upper left of keypad KEYA3 Upper right of keypad KEYB2 Center of keypad KEYC1 Lower left of keypad KEYC3 Lower right of keypad KEYBTAB Back tab key KEYBEG Beg(inning) key KEYCANCEL Cancel key KEYCLOSE Close key KEYCOMMAND Cmd (command) key KEYCOPY Copy key KEYCREATE Create key KEYEND End key KEYEXIT Exit key KEYFIND Find key KEYHELP Help key KEYMARK Mark key KEYMESSAGE Message key KEYMOUSE Mouse event read KEYMOVE Move key KEYNEXT Next object key KEYOPEN Open key KEYOPTIONS Options key
KEYPREVIOUS Previous object key KEYREDO Redo key KEYREFERENCE Ref(erence) key KEYREFRESH Refresh key KEYREPLACE Replace key KEYRESIZE Screen resized KEYRESTART Restart key KEYRESUME Resume key KEYSAVE Save key KEYSBEG Shifted beginning key KEYSCANCEL Shifted cancel key KEYSCOMMAND Shifted command key KEYSCOPY Shifted copy key KEYSCREATE Shifted create key KEYSDC Shifted delete char key KEYSDL Shifted delete line key KEYSELECT Select key KEYSEND Shifted end key KEYSEOL Shifted clear line key KEYSEXIT Shifted exit key KEYSFIND Shifted find key KEYSHELP Shifted help key KEYSHOME Shifted home key KEYSIC Shifted input key KEYSLEFT Shifted left arrow key KEYSMESSAGE Shifted message key KEYSMOVE Shifted move key KEYSNEXT Shifted next keyKEYSOPTIONS Shifted options key
KEYSPREVIOUS Shifted prev key KEYSPRINT Shifted print key KEYSREDO Shifted redo key KEYSREPLACE Shifted replace key KEYSRIGHT Shifted right arrow KEYSRSUME Shifted resume key KEYSSAVE Shifted save key KEYSSUSPEND Shifted suspend key KEYSUNDO Shifted undo key KEYSUSPEND Suspend key KEYUNDO Undo key Keypad is arranged like this:+---+---+----+
| AA11 | uupp | AA33 |+---+---+----+
|lleefftt | BB22 | rriigghhtt |+---+---+----+
| CC11 | ddoowwnn | CC33 |+---+---+----+
The hhaasskkeeyy routine takes a key value from the above list, and returns TRUE or FALSE according to whether the current terminal type recognizes a key with that value. Note that a few values do not correspond to a real key, e.g., KKEEYYRREESSIIZZEE and KKEEYYMMOOUUSSEE. See rreessiizzeetteerrmm(3X) for more details about KKEEYYRREESSIIZZEE, and ccuurrssmmoouussee(3X) for a discussion of KKEEYYMMOOUUSSEE. RREETTUURRNN VVAALLUUEE All routines return the integer EERRRR upon failure and an integer valueother than EERRRR (OOKK in the case of ungetch()) upon successful comple-
tion. uunnggeettcchh returns an error if there is no more room in the FIFO. wwggeettcchh returns an error if the window pointer is null, or if its timeout expires without having any data. NNOOTTEESS Use of the escape key by a programmer for a single character function is discouraged, as it will cause a delay of up to one second while thekeypad code looks for a following function-key sequence.
Note that some keys may be the same as commonly used control keys, e.g., KKEEYYEENNTTEERR versus control/M, KKEEYYBBAACCKKSSPPAACCEE versus control/H. Some curses implementations may differ according to whether they treat these control keys specially (and ignore the terminfo), or use the terminfo definitions. NNccuurrsseess uses the terminfo definition. If it says thatKKEEYYEENNTTEERR is control/M, ggeettcchh will return KKEEYYEENNTTEERR when you press con-
trol/M. When using ggeettcchh, wwggeettcchh, mmvvggeettcchh, or mmvvwwggeettcchh, nocbreak mode (nnooccbbrreeaakk) and echo mode (eecchhoo) should not be used at the same time. Depending on the state of the tty driver when each character is typed, the program may produce undesirable results. Note that ggeettcchh, mmvvggeettcchh, and mmvvwwggeettcchh may be macros.Historically, the set of keypad macros was largely defined by the ex-
tremely function-key-rich keyboard of the AT&T 7300, aka 3B1, aka Sa-
fari 4. Modern personal computers usually have only a small subset ofthese. IBM PC-style consoles typically support little more than
KKEEYYUUPP, KKEEYYDDOOWWNN, KKEEYYLLEEFFTT, KKEEYYRRIIGGHHTT, KKEEYYHHOOMMEE, KKEEYYEENNDD, KKEEYYNNPPAAGGEE, KKEEYYPPPPAAGGEE, and function keys 1 through 12. The Ins key is usually mapped to KKEEYYIICC. PPOORRTTAABBIILLIITTYY The *get* functions are described in the XSI Curses standard, Issue 4.They read single-byte characters only. The standard specifies that
they return EERRRR on failure, but specifies no error conditions. The echo behavior of these functions on input of KKEEYY or backspacecharacters was not specified in the SVr4 documentation. This descrip-
tion is adopted from the XSI Curses standard. The behavior of ggeettcchh and friends in the presence of handled signals is unspecified in the SVr4 and XSI Curses documentation. Under historical curses implementations, it varied depending on whether the operating system's implementation of handled signal receipt interrupts a rreeaadd(2) call in progress or not, and also (in some implementations) dependingon whether an input timeout or non-blocking mode has been set.
Programmers concerned about portability should be prepared for either of two cases: (a) signal receipt does not interrupt ggeettcchh; (b) signal receipt interrupts ggeettcchh and causes it to return ERR with eerrrrnnoo set toEEIINNTTRR. Under the nnccuurrsseess implementation, handled signals never inter-
rupt ggeettcchh. The hhaasskkeeyy function is unique to nnccuurrsseess. We recommend that any code using it be conditionalized on the NNCCUURRSSEESSVVEERRSSIIOONN feature macro.SEE ALSO
ccuurrsseess(3X), ccuurrssiinnooppttss(3X), ccuurrssmmoouussee(3X), ccuurrssmmoovvee(3X), ccuurrssrree-
ffrreesshh(3X), rreessiizzeetteerrmm(3X). cursgetch(3X)