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| * @Id: curs_getstr.3x,v 1.33 2021/05/22 21:36:35 tom Exp @ |
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| <H1 class="no-header">curs_getstr 3x</H1> |
| <PRE> |
| <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG> <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG> |
| |
| |
| |
| |
| </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE> |
| <STRONG>getstr</STRONG>, <STRONG>getnstr</STRONG>, <STRONG>wgetstr</STRONG>, <STRONG>wgetnstr</STRONG>, <STRONG>mvgetstr</STRONG>, <STRONG>mvgetnstr</STRONG>, <STRONG>mvwgetstr</STRONG>, |
| <STRONG>mvwgetnstr</STRONG> - accept character strings 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>getstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG> |
| <STRONG>int</STRONG> <STRONG>getnstr(char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG> |
| <STRONG>int</STRONG> <STRONG>wgetstr(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG> |
| <STRONG>int</STRONG> <STRONG>wgetnstr(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG> |
| |
| <STRONG>int</STRONG> <STRONG>mvgetstr(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG> |
| <STRONG>int</STRONG> <STRONG>mvwgetstr(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>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>);</STRONG> |
| <STRONG>int</STRONG> <STRONG>mvgetnstr(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG> |
| <STRONG>int</STRONG> <STRONG>mvwgetnstr(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>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>n</EM><STRONG>);</STRONG> |
| |
| |
| </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE> |
| The function <STRONG>getstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, until |
| a newline or carriage return is received (the terminating character is |
| not included in the returned string). The resulting value is placed in |
| the area pointed to by the character pointer <EM>str</EM>, followed by a NUL. |
| |
| The <STRONG>getnstr</STRONG> function reads from the <EM>stdscr</EM> default window. The other |
| functions, such as <STRONG>wgetnstr</STRONG>, read from the window given as a parameter. |
| |
| <STRONG>getnstr</STRONG> reads at most <EM>n</EM> characters, thus preventing a possible overflow |
| of the input buffer. Any attempt to enter more characters (other than |
| the terminating newline or carriage return) causes a beep. Function |
| keys also cause a beep and are ignored. |
| |
| The user's <EM>erase</EM> and <EM>kill</EM> characters are interpreted: |
| |
| <STRONG>o</STRONG> The <EM>erase</EM> character (e.g., <STRONG>^H</STRONG>) erases the character at the end of |
| the buffer, moving the cursor to the left. |
| |
| If <EM>keypad</EM> mode is on for the window, <STRONG>KEY_LEFT</STRONG> and <STRONG>KEY_BACKSPACE</STRONG> are |
| both considered equivalent to the user's erase character. |
| |
| <STRONG>o</STRONG> The <EM>kill</EM> character (e.g., <STRONG>^U</STRONG>) erases the entire buffer, leaving the |
| cursor at the beginning of the buffer. |
| |
| Characters input are echoed only if <STRONG>echo</STRONG> is currently on. In that |
| case, backspace is echoed as deletion of the previous character (typi- |
| cally a left motion). |
| |
| |
| </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE> |
| All routines return the integer <STRONG>ERR</STRONG> upon failure and an <STRONG>OK</STRONG> (SVr4 speci- |
| fies only "an integer value other than <STRONG>ERR</STRONG>") upon successful comple- |
| tion. |
| |
| X/Open defines no error conditions. |
| |
| In this implementation, these functions return an error if the window |
| pointer is null, or if its timeout expires without having any data. |
| |
| This implementation provides an extension as well. If a <STRONG>SIGWINCH</STRONG> in- |
| terrupts the function, it will return <STRONG>KEY_RESIZE</STRONG> rather than <STRONG>OK</STRONG> or <STRONG>ERR</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> |
| Note that <STRONG>getstr</STRONG>, <STRONG>mvgetstr</STRONG>, and <STRONG>mvwgetstr</STRONG> may be macros. |
| |
| |
| </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE> |
| These functions are described in the XSI Curses standard, Issue 4. |
| They read single-byte characters only. The standard does not define |
| any error conditions. This implementation returns <STRONG>ERR</STRONG> if the window |
| pointer is null, or if the lower-level <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> call returns an <STRONG>ERR</STRONG>. |
| |
| SVr3 and early SVr4 curses implementations did not reject function |
| keys; the SVr4.0 documentation claimed that "special keys" (such as |
| function keys, "home" key, "clear" key, <EM>etc</EM>.) are "interpreted", with- |
| out giving details. It lied. In fact, the "character" value appended |
| to the string by those implementations was predictable but not useful |
| (being, in fact, the low-order eight bits of the key's KEY_ value). |
| |
| The functions <STRONG>getnstr</STRONG>, <STRONG>mvgetnstr</STRONG>, and <STRONG>mvwgetnstr</STRONG> were present but not |
| documented in SVr4. |
| |
| X/Open Curses, Issue 5 (2007) stated that these functions "read at most |
| <EM>n</EM> bytes" but did not state whether the terminating NUL is counted in |
| that limit. X/Open Curses, Issue 7 (2009) changed that to say they |
| "read at most <EM>n</EM>-1 bytes" to allow for the terminating NUL. As of 2018, |
| some implementations do, some do not count it: |
| |
| <STRONG>o</STRONG> ncurses 6.1 and PDCurses do not count the NUL in the given limit, |
| while |
| |
| <STRONG>o</STRONG> Solaris SVr4 and NetBSD curses count the NUL as part of the limit. |
| |
| <STRONG>o</STRONG> Solaris xcurses provides both: its wide-character <STRONG>wget_nstr</STRONG> re- |
| serves a NUL, but its <STRONG>wgetnstr</STRONG> does not count the NUL consistently. |
| |
| In SVr4 curses, a negative value of <EM>n</EM> tells <STRONG>wgetnstr</STRONG> to assume that the |
| caller's buffer is large enough to hold the result, i.e., to act like |
| <STRONG>wgetstr</STRONG>. X/Open Curses does not mention this (or anything related to |
| negative or zero values of <EM>n</EM>), however most implementations use the |
| feature, with different limits: |
| |
| <STRONG>o</STRONG> Solaris SVr4 curses and PDCurses limit the result to 255 bytes. |
| Other Unix systems than Solaris are likely to use the same limit. |
| |
| <STRONG>o</STRONG> Solaris xcurses limits the result to <STRONG>LINE_MAX</STRONG> bytes. |
| |
| <STRONG>o</STRONG> NetBSD 7 assumes no particular limit for the result from <STRONG>wgetstr</STRONG>. |
| However, it limits the <STRONG>wgetnstr</STRONG> parameter <EM>n</EM> to ensure that it is |
| greater than zero. |
| |
| A comment in NetBSD's source code states that this is specified in |
| SUSv2. |
| |
| <STRONG>o</STRONG> ncurses (before 6.2) assumes no particular limit for the result |
| from <STRONG>wgetstr</STRONG>, and treats the <EM>n</EM> parameter of <STRONG>wgetnstr</STRONG> like SVr4 |
| curses. |
| |
| <STRONG>o</STRONG> ncurses 6.2 uses <STRONG>LINE_MAX</STRONG>, or a larger (system-dependent) value |
| which the <STRONG>sysconf</STRONG> function may provide. If neither <STRONG>LINE_MAX</STRONG> or |
| <STRONG>sysconf</STRONG> is available, ncurses uses the POSIX value for <STRONG>LINE_MAX</STRONG> (a |
| 2048 byte limit). In either case, it reserves a byte for the ter- |
| minating NUL. |
| |
| Although <STRONG>getnstr</STRONG> is equivalent to a series of calls to <STRONG>getch</STRONG>, it also |
| makes changes to the curses modes to allow simple editing of the input |
| buffer: |
| |
| <STRONG>o</STRONG> <STRONG>getnstr</STRONG> saves the current value of the <STRONG>nl</STRONG>, <STRONG>echo</STRONG>, <STRONG>raw</STRONG> and <STRONG>cbreak</STRONG> |
| modes, and sets <STRONG>nl</STRONG>, <STRONG>noecho</STRONG>, <STRONG>noraw</STRONG>, and <STRONG>cbreak</STRONG>. |
| |
| <STRONG>getnstr</STRONG> handles the echoing of characters, rather than relying on |
| the caller to set an appropriate mode. |
| |
| <STRONG>o</STRONG> It also obtains the <EM>erase</EM> and <EM>kill</EM> characters from <STRONG>erasechar</STRONG> and |
| <STRONG>killchar</STRONG>, respectively. |
| |
| <STRONG>o</STRONG> On return, <STRONG>getnstr</STRONG> restores the modes to their previous values. |
| |
| Other implementations differ in their treatment of special characters: |
| |
| <STRONG>o</STRONG> While they may set the <EM>echo</EM> mode, other implementations do not mod- |
| ify the <EM>raw</EM> mode, They may take the <EM>cbreak</EM> mode set by the caller |
| into account when deciding whether to handle echoing within <STRONG>getnstr</STRONG> |
| or as a side-effect of the <STRONG>getch</STRONG> calls. |
| |
| <STRONG>o</STRONG> The original ncurses (as pcurses in 1986) set <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> when |
| accepting input for <STRONG>getnstr</STRONG>. That may have been done to make func- |
| tion- and cursor-keys work; it is not necessary with ncurses. |
| |
| Since 1995, ncurses has provided signal handlers for INTR and QUIT |
| (e.g., <STRONG>^C</STRONG> or <STRONG>^\</STRONG>). With the <STRONG>noraw</STRONG> and <STRONG>cbreak</STRONG> settings, those may |
| catch a signal and stop the program, where other implementations |
| allow one to enter those characters in the buffer. |
| |
| <STRONG>o</STRONG> Starting in 2021 (ncurses 6.3), <STRONG>getnstr</STRONG> sets <STRONG>raw</STRONG>, rather than <STRONG>noraw</STRONG> |
| and <STRONG>cbreak</STRONG> for better compatibility with SVr4-curses, e.g., allow- |
| ing one to enter a <STRONG>^C</STRONG> into the buffer. |
| |
| |
| </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_getch.3x.html">curs_getch(3x)</A></STRONG>, <STRONG><A HREF="curs_termattrs.3x.html">curs_termattrs(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>. |
| |
| |
| |
| <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(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></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> |
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