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| <H1 class="no-header">curs_getch 3x</H1> |
| <PRE> |
| <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> |
| |
| |
| |
| |
| </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE> |
| <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, <STRONG>mvwgetch</STRONG>, <STRONG>ungetch</STRONG>, <STRONG>has_key</STRONG> - get (or push back) |
| characters from <STRONG>curses</STRONG> terminal keyboard |
| |
| |
| </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE> |
| <STRONG>#include</STRONG> <STRONG><curses.h></STRONG> |
| |
| <STRONG>int</STRONG> <STRONG>getch(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>wgetch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win);</EM> |
| |
| <STRONG>int</STRONG> <STRONG>mvgetch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>);</STRONG> |
| <STRONG>int</STRONG> <STRONG>mvwgetch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>);</STRONG> |
| |
| <STRONG>int</STRONG> <STRONG>ungetch(int</STRONG> <EM>ch</EM><STRONG>);</STRONG> |
| |
| /* extension */ |
| <STRONG>int</STRONG> <STRONG>has_key(int</STRONG> <EM>ch</EM><STRONG>);</STRONG> |
| |
| |
| </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE> |
| |
| </PRE><H3><a name="h3-Reading-characters">Reading characters</a></H3><PRE> |
| The <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG> and <STRONG>mvwgetch</STRONG>, routines read a character from |
| the window. In no-delay mode, if no input is waiting, the value <STRONG>ERR</STRONG> is |
| returned. In delay mode, the program waits until the system passes |
| text through to the program. Depending on the setting of <STRONG>cbreak</STRONG>, 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. |
| |
| If <STRONG>echo</STRONG> is enabled, and the window is not a pad, then the character |
| will also be echoed into the designated window according to the follow- |
| ing rules: |
| |
| <STRONG>o</STRONG> If the character is the current erase character, left arrow, or |
| backspace, the cursor is moved one space to the left and that |
| screen position is erased as if <STRONG>delch</STRONG> had been called. |
| |
| <STRONG>o</STRONG> If the character value is any other <STRONG>KEY_</STRONG> define, the user is alert- |
| ed with a <STRONG>beep</STRONG> call. |
| |
| <STRONG>o</STRONG> If the character is a carriage-return, and if <STRONG>nl</STRONG> is enabled, it is |
| translated to a line-feed after echoing. |
| |
| <STRONG>o</STRONG> 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 <STRONG>wrefresh</STRONG>, <STRONG>wrefresh</STRONG> will be called before another character |
| is read. |
| |
| |
| </PRE><H3><a name="h3-Keypad-mode">Keypad mode</a></H3><PRE> |
| If <STRONG>keypad</STRONG> is <STRONG>TRUE</STRONG>, and a function key is pressed, the token for that |
| function key is returned instead of the raw characters: |
| |
| <STRONG>o</STRONG> The predefined function keys are listed in <STRONG><curses.h></STRONG> as macros |
| with values outside the range of 8-bit characters. Their names be- |
| gin with <STRONG>KEY_</STRONG>. |
| |
| <STRONG>o</STRONG> Other (user-defined) function keys which may be defined using <STRONG>de-</STRONG> |
| <STRONG><A HREF="define_key.3x.html">fine_key(3x)</A></STRONG> have no names, but also are expected to have values |
| outside the range of 8-bit characters. |
| |
| 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), <STRONG>curses</STRONG> |
| sets a timer. If the remainder of the sequence does not come in within |
| the designated time, the character is passed through; otherwise, the |
| function 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. |
| |
| In <STRONG>ncurses</STRONG>, the timer normally expires after the value in <STRONG>ESCDELAY</STRONG> (see |
| <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>). If <STRONG>notimeout</STRONG> is <STRONG>TRUE</STRONG>, 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 no- |
| timeout mode after pressing the escape key until another key is |
| pressed. |
| |
| |
| </PRE><H3><a name="h3-Ungetting-characters">Ungetting characters</a></H3><PRE> |
| The <STRONG>ungetch</STRONG> routine places <EM>ch</EM> back onto the input queue to be returned |
| by the next call to <STRONG>wgetch</STRONG>. There is just one input queue for all win- |
| dows. |
| |
| |
| </PRE><H3><a name="h3-Predefined-key-codes">Predefined key-codes</a></H3><PRE> |
| The following special keys are defined in <STRONG><curses.h></STRONG>. |
| |
| <STRONG>o</STRONG> Except for the special case <STRONG>KEY_RESIZE</STRONG>, it is necessary to enable |
| <STRONG>keypad</STRONG> for <STRONG>getch</STRONG> to return these codes. |
| |
| <STRONG>o</STRONG> Not all of these are necessarily supported on any particular termi- |
| nal. |
| |
| <STRONG>o</STRONG> The naming convention may seem obscure, with some apparent mis- |
| spellings (such as "RSUME" for "resume"). The names correspond to |
| the long terminfo capability names for the keys, and were defined |
| long ago, in the 1980s. |
| |
| <EM>Name</EM> <EM>Key</EM> <EM>name</EM> |
| ------------------------------------------------- |
| KEY_BREAK Break key |
| KEY_DOWN The four arrow keys ... |
| KEY_UP |
| KEY_LEFT |
| KEY_RIGHT |
| KEY_HOME Home key (upward+left arrow) |
| KEY_BACKSPACE Backspace |
| KEY_F0 Function keys; space for 64 keys |
| is reserved. |
| KEY_F(<EM>n</EM>) For 0 <= <EM>n</EM> <= 63 |
| KEY_DL Delete line |
| KEY_IL Insert line |
| KEY_DC Delete character |
| KEY_IC Insert char or enter insert mode |
| KEY_EIC Exit insert char mode |
| KEY_CLEAR Clear screen |
| KEY_EOS Clear to end of screen |
| KEY_EOL Clear to end of line |
| KEY_SF Scroll 1 line forward |
| KEY_SR Scroll 1 line backward (reverse) |
| KEY_NPAGE Next page |
| KEY_PPAGE Previous page |
| KEY_STAB Set tab |
| KEY_CTAB Clear tab |
| KEY_CATAB Clear all tabs |
| KEY_ENTER Enter or send |
| KEY_SRESET Soft (partial) reset |
| KEY_RESET Reset or hard reset |
| |
| KEY_PRINT Print or copy |
| KEY_LL Home down or bottom (lower left) |
| KEY_A1 Upper left of keypad |
| KEY_A3 Upper right of keypad |
| KEY_B2 Center of keypad |
| KEY_C1 Lower left of keypad |
| KEY_C3 Lower right of keypad |
| KEY_BTAB Back tab key |
| KEY_BEG Beg(inning) key |
| KEY_CANCEL Cancel key |
| KEY_CLOSE Close key |
| KEY_COMMAND Cmd (command) key |
| KEY_COPY Copy key |
| KEY_CREATE Create key |
| KEY_END End key |
| KEY_EXIT Exit key |
| KEY_FIND Find key |
| KEY_HELP Help key |
| KEY_MARK Mark key |
| KEY_MESSAGE Message key |
| KEY_MOUSE Mouse event read |
| KEY_MOVE Move key |
| KEY_NEXT Next object key |
| KEY_OPEN Open key |
| KEY_OPTIONS Options key |
| KEY_PREVIOUS Previous object key |
| KEY_REDO Redo key |
| KEY_REFERENCE Ref(erence) key |
| KEY_REFRESH Refresh key |
| KEY_REPLACE Replace key |
| KEY_RESIZE Screen resized |
| KEY_RESTART Restart key |
| KEY_RESUME Resume key |
| KEY_SAVE Save key |
| KEY_SBEG Shifted beginning key |
| KEY_SCANCEL Shifted cancel key |
| KEY_SCOMMAND Shifted command key |
| KEY_SCOPY Shifted copy key |
| KEY_SCREATE Shifted create key |
| KEY_SDC Shifted delete char key |
| KEY_SDL Shifted delete line key |
| KEY_SELECT Select key |
| KEY_SEND Shifted end key |
| KEY_SEOL Shifted clear line key |
| KEY_SEXIT Shifted exit key |
| KEY_SFIND Shifted find key |
| KEY_SHELP Shifted help key |
| KEY_SHOME Shifted home key |
| KEY_SIC Shifted input key |
| KEY_SLEFT Shifted left arrow key |
| KEY_SMESSAGE Shifted message key |
| KEY_SMOVE Shifted move key |
| KEY_SNEXT Shifted next key |
| KEY_SOPTIONS Shifted options key |
| KEY_SPREVIOUS Shifted prev key |
| KEY_SPRINT Shifted print key |
| KEY_SREDO Shifted redo key |
| KEY_SREPLACE Shifted replace key |
| KEY_SRIGHT Shifted right arrow |
| KEY_SRSUME Shifted resume key |
| KEY_SSAVE Shifted save key |
| KEY_SSUSPEND Shifted suspend key |
| KEY_SUNDO Shifted undo key |
| KEY_SUSPEND Suspend key |
| KEY_UNDO Undo key |
| |
| Keypad is arranged like this: |
| |
| +-----+------+-------+ |
| | <STRONG>A1</STRONG> | <STRONG>up</STRONG> | <STRONG>A3</STRONG> | |
| +-----+------+-------+ |
| |<STRONG>left</STRONG> | <STRONG>B2</STRONG> | <STRONG>right</STRONG> | |
| +-----+------+-------+ |
| | <STRONG>C1</STRONG> | <STRONG>down</STRONG> | <STRONG>C3</STRONG> | |
| +-----+------+-------+ |
| A few of these predefined values do <EM>not</EM> correspond to a real key: |
| |
| <STRONG>o</STRONG> <STRONG>KEY_RESIZE</STRONG> is returned when the <STRONG>SIGWINCH</STRONG> signal has been detected |
| (see <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> and <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>). This code is returned |
| whether or not <STRONG>keypad</STRONG> has been enabled. |
| |
| <STRONG>o</STRONG> <STRONG>KEY_MOUSE</STRONG> is returned for mouse-events (see <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG>). This |
| code relies upon whether or not <STRONG><A HREF="curs_inopts.3x.html">keypad(3x)</A></STRONG> has been enabled, be- |
| cause (e.g., with <EM>xterm</EM> mouse prototocol) ncurses must read escape |
| sequences, just like a function key. |
| |
| |
| </PRE><H3><a name="h3-Testing-key-codes">Testing key-codes</a></H3><PRE> |
| The <STRONG>has_key</STRONG> routine takes a key-code value from the above list, and re- |
| turns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG> according to whether the current terminal type rec- |
| ognizes a key with that value. |
| |
| The library also supports these extensions: |
| |
| <STRONG>define_key</STRONG> |
| defines a key-code for a given string (see <STRONG><A HREF="define_key.3x.html">define_key(3x)</A></STRONG>). |
| |
| <STRONG>key_defined</STRONG> |
| checks if there is a key-code defined for a given string (see |
| <STRONG><A HREF="key_defined.3x.html">key_defined(3x)</A></STRONG>). |
| |
| |
| </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE> |
| All routines return the integer <STRONG>ERR</STRONG> upon failure and an integer value |
| other than <STRONG>ERR</STRONG> (<STRONG>OK</STRONG> in the case of <STRONG>ungetch</STRONG>) upon successful completion. |
| |
| <STRONG>ungetch</STRONG> |
| returns <STRONG>ERR</STRONG> if there is no more room in the FIFO. |
| |
| <STRONG>wgetch</STRONG> |
| returns <STRONG>ERR</STRONG> if the window pointer is null, or if its timeout |
| expires without having any data, or if the execution was inter- |
| rupted by a signal (<STRONG>errno</STRONG> will be set to <STRONG>EINTR</STRONG>). |
| |
| Functions with a "mv" prefix first perform a cursor movement using |
| <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if |
| the window pointer is null. |
| |
| |
| </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE> |
| 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 the |
| keypad code looks for a following function-key sequence. |
| |
| Some keys may be the same as commonly used control keys, e.g., <STRONG>KEY_EN-</STRONG> |
| <STRONG>TER</STRONG> versus control/M, <STRONG>KEY_BACKSPACE</STRONG> versus control/H. Some curses im- |
| plementations may differ according to whether they treat these control |
| keys specially (and ignore the terminfo), or use the terminfo defini- |
| tions. <STRONG>Ncurses</STRONG> uses the terminfo definition. If it says that <STRONG>KEY_EN-</STRONG> |
| <STRONG>TER</STRONG> is control/M, <STRONG>getch</STRONG> will return <STRONG>KEY_ENTER</STRONG> when you press control/M. |
| |
| Generally, <STRONG>KEY_ENTER</STRONG> denotes the character(s) sent by the <EM>Enter</EM> key on |
| the numeric keypad: |
| |
| <STRONG>o</STRONG> the terminal description lists the most useful keys, |
| |
| <STRONG>o</STRONG> the <EM>Enter</EM> key on the regular keyboard is already handled by the |
| standard ASCII characters for carriage-return and line-feed, |
| |
| <STRONG>o</STRONG> depending on whether <STRONG>nl</STRONG> or <STRONG>nonl</STRONG> was called, pressing "Enter" on the |
| regular keyboard may return either a carriage-return or line-feed, |
| and finally |
| |
| <STRONG>o</STRONG> "Enter or send" is the standard description for this key. |
| |
| When using <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, or <STRONG>mvwgetch</STRONG>, nocbreak mode |
| (<STRONG>nocbreak</STRONG>) and echo mode (<STRONG>echo</STRONG>) 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 <STRONG>getch</STRONG>, <STRONG>mvgetch</STRONG>, and <STRONG>mvwgetch</STRONG> 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 of |
| these. IBM PC-style consoles typically support little more than |
| <STRONG>KEY_UP</STRONG>, <STRONG>KEY_DOWN</STRONG>, <STRONG>KEY_LEFT</STRONG>, <STRONG>KEY_RIGHT</STRONG>, <STRONG>KEY_HOME</STRONG>, <STRONG>KEY_END</STRONG>, <STRONG>KEY_NPAGE</STRONG>, |
| <STRONG>KEY_PPAGE</STRONG>, and function keys 1 through 12. The Ins key is usually |
| mapped to <STRONG>KEY_IC</STRONG>. |
| |
| |
| </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE> |
| The *get* functions are described in the XSI Curses standard, Issue 4. |
| They read single-byte characters only. The standard specifies that |
| they return <STRONG>ERR</STRONG> on failure, but specifies no error conditions. |
| |
| The echo behavior of these functions on input of <STRONG>KEY_</STRONG> or backspace |
| characters was not specified in the SVr4 documentation. This descrip- |
| tion is adopted from the XSI Curses standard. |
| |
| The behavior of <STRONG>getch</STRONG> 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 <STRONG>read(2)</STRONG> |
| call in progress or not, and also (in some implementations) depending |
| on whether an input timeout or non-blocking mode has been set. |
| |
| <STRONG>KEY_MOUSE</STRONG> is mentioned in XSI Curses, along with a few related terminfo |
| capabilities, but no higher-level functions use the feature. The im- |
| plementation in ncurses is an extension. |
| |
| <STRONG>KEY_RESIZE</STRONG> is an extension first implemented for ncurses. NetBSD curs- |
| es later added this extension. |
| |
| Programmers concerned about portability should be prepared for either |
| of two cases: (a) signal receipt does not interrupt <STRONG>getch</STRONG>; (b) signal |
| receipt interrupts <STRONG>getch</STRONG> and causes it to return <STRONG>ERR</STRONG> with <STRONG>errno</STRONG> set to |
| <STRONG>EINTR</STRONG>. |
| |
| The <STRONG>has_key</STRONG> function is unique to <STRONG>ncurses</STRONG>. We recommend that any code |
| using it be conditionalized on the <STRONG>NCURSES_VERSION</STRONG> feature macro. |
| |
| |
| </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE> |
| <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>, <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG>, <STRONG><A HREF="curs_move.3x.html">curs_move(3x)</A></STRONG>, <STRONG>curs_out-</STRONG> |
| <STRONG><A HREF="curs_outopts.3x.html">opts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>. |
| |
| Comparable functions in the wide-character (ncursesw) library are de- |
| scribed in <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>. |
| |
| |
| |
| <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG> |
| </PRE> |
| <div class="nav"> |
| <ul> |
| <li><a href="#h2-NAME">NAME</a></li> |
| <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li> |
| <li><a href="#h2-DESCRIPTION">DESCRIPTION</a> |
| <ul> |
| <li><a href="#h3-Reading-characters">Reading characters</a></li> |
| <li><a href="#h3-Keypad-mode">Keypad mode</a></li> |
| <li><a href="#h3-Ungetting-characters">Ungetting characters</a></li> |
| <li><a href="#h3-Predefined-key-codes">Predefined key-codes</a></li> |
| <li><a href="#h3-Testing-key-codes">Testing key-codes</a></li> |
| </ul> |
| </li> |
| <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li> |
| <li><a href="#h2-NOTES">NOTES</a></li> |
| <li><a href="#h2-PORTABILITY">PORTABILITY</a></li> |
| <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li> |
| </ul> |
| </div> |
| </BODY> |
| </HTML> |
