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| <H1 class="no-header">curs_scanw 3x</H1> |
| <PRE> |
| <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG> <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG> |
| |
| |
| |
| |
| </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE> |
| <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>, <STRONG>mvwscanw</STRONG>, <STRONG>vwscanw</STRONG>, <STRONG>vw_scanw</STRONG> - convert formatted |
| input from a <STRONG>curses</STRONG> window |
| |
| |
| </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE> |
| <STRONG>#include</STRONG> <STRONG><curses.h></STRONG> |
| |
| <STRONG>int</STRONG> <STRONG>scanw(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG> |
| <STRONG>int</STRONG> <STRONG>wscanw(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG> |
| <STRONG>int</STRONG> <STRONG>mvscanw(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG> |
| <STRONG>int</STRONG> <STRONG>mvwscanw(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>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG> |
| |
| <STRONG>int</STRONG> <STRONG>vw_scanw(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>va_list</STRONG> <EM>varglist</EM><STRONG>);</STRONG> |
| |
| /* obsolete */ |
| <STRONG>int</STRONG> <STRONG>vwscanw(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>va_list</STRONG> <EM>varglist</EM><STRONG>);</STRONG> |
| |
| |
| </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE> |
| The <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG> and <STRONG>mvscanw</STRONG> routines are analogous to <STRONG>scanf</STRONG> [see |
| <STRONG>scanf(3)</STRONG>]. The effect of these routines is as though <STRONG>wgetstr</STRONG> were |
| called on the window, and the resulting line used as input for |
| <STRONG>sscanf(3)</STRONG>. Fields which do not map to a variable in the <EM>fmt</EM> field are |
| lost. |
| |
| The <STRONG>vwscanw</STRONG> and <STRONG>vw_scanw</STRONG> routines are analogous to <STRONG>vscanf(3)</STRONG>. They |
| perform a <STRONG>wscanw</STRONG> using a variable argument list. The third argument is |
| a <EM>va</EM><STRONG>_</STRONG><EM>list</EM>, a pointer to a list of arguments, as defined in <STRONG><stdarg.h></STRONG>. |
| |
| |
| </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE> |
| <STRONG>vwscanw</STRONG> returns <STRONG>ERR</STRONG> on failure and an integer equal to the number of |
| fields scanned on success. |
| |
| Applications may use the return value from the <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG> |
| and <STRONG>mvwscanw</STRONG> routines to determine the number of fields which were |
| mapped in the call. |
| |
| 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-HISTORY">HISTORY</a></H2><PRE> |
| While <STRONG>scanw</STRONG> was implemented in 4BSD, none of the BSD releases used it |
| until 4.4BSD (in a game). That early version of curses was before the |
| ANSI C standard. It did not use <varargs.h>, though that was |
| available. In 1991 (a couple of years after SVr4 was generally |
| available, and after the C standard was published), other developers |
| updated the library, using <stdarg.h> internally in 4.4BSD curses. |
| Even with this improvement, BSD curses did not use function prototypes |
| (or even declare functions) in the <curses.h> header until 1992. |
| |
| SVr2 documented <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG> tersely as "scanf through <EM>stdscr</EM>" and |
| tersely as "scanf through <EM>win</EM>", respectively. |
| |
| SVr3 added <STRONG>mvscanw</STRONG>, and <STRONG>mvwscanw</STRONG>, with a three-line summary saying that |
| they were analogous to <STRONG>scanf(3)</STRONG>, explaining that the string which would |
| be output from <STRONG>scanf(3)</STRONG> would instead be output using <STRONG>waddstr</STRONG> on the |
| given window. SVr3 also added <STRONG>vwscanw</STRONG>, saying that the third parameter |
| is a <STRONG>va_list</STRONG>, defined in <varargs.h>, and referring the reader to the |
| manual pages for <EM>varargs</EM> and <EM>vprintf</EM> for detailed descriptions. |
| (Because the SVr3 documentation does not mention <EM>vscanf</EM>, that reference |
| to <EM>vprintf</EM> may not be an error). |
| |
| SVr4 added no new variations of <STRONG>scanw</STRONG>, but provided for using |
| <varargs.h> or <stdarg.h> to define the <STRONG>va_list</STRONG> type. |
| |
| X/Open Curses added <STRONG>vw_scanw</STRONG> to replace <STRONG>vwscanw</STRONG>, stating that its |
| <STRONG>va_list</STRONG> definition requires <stdarg.h>. |
| |
| |
| </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE> |
| In this implementation, <STRONG>vw_scanw</STRONG> and <STRONG>vwscanw</STRONG> are equivalent, to support |
| legacy applications. However, the latter (<STRONG>vwscanw</STRONG>) is obsolete: |
| |
| <STRONG>o</STRONG> The XSI Curses standard, Issue 4 described these functions, noting |
| that the function <STRONG>vwscanw</STRONG> is marked TO BE WITHDRAWN, and is to be |
| replaced by a function <STRONG>vw_scanw</STRONG> using the <STRONG><stdarg.h></STRONG> interface. |
| |
| <STRONG>o</STRONG> The Single Unix Specification, Version 2 states that <STRONG>vw_scanw</STRONG> is |
| preferred to <STRONG>vwscanw</STRONG> since the latter requires including |
| <STRONG><varargs.h></STRONG>, which cannot be used in the same file as <STRONG><stdarg.h></STRONG>. |
| This implementation uses <STRONG><stdarg.h></STRONG> for both, because that header |
| is included in <STRONG><curses.h</STRONG>>. |
| |
| <STRONG>o</STRONG> X/Open Curses, Issue 5 (December 2007) marked <STRONG>vwscanw</STRONG> (along with |
| <STRONG>vwprintw</STRONG> and the termcap interface) as withdrawn. |
| |
| Both XSI and The Single Unix Specification, Version 2 state that these |
| functions return <STRONG>ERR</STRONG> or <STRONG>OK</STRONG>. |
| |
| <STRONG>o</STRONG> Since the underlying <STRONG>scanf(3)</STRONG> can return the number of items |
| scanned, and the SVr4 code was documented to use this feature, this |
| is probably an editing error which was introduced in XSI, rather |
| than being done intentionally. |
| |
| <STRONG>o</STRONG> This implementation returns the number of items scanned, for |
| compatibility with SVr4 curses. As of 2018, NetBSD curses also |
| returns the number of items scanned. Both ncurses and NetBSD |
| curses call <STRONG>vsscanf</STRONG> to scan the string, which returns <STRONG>EOF</STRONG> on error. |
| |
| <STRONG>o</STRONG> Portable applications should only test if the return value is <STRONG>ERR</STRONG>, |
| since the <STRONG>OK</STRONG> value (zero) is likely to be misleading. |
| |
| One possible way to get useful results would be to use a "%n" |
| conversion at the end of the format string to ensure that something |
| was processed. |
| |
| |
| </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_getstr.3x.html">curs_getstr(3x)</A></STRONG>, <STRONG><A HREF="curs_printw.3x.html">curs_printw(3x)</A></STRONG>, <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>, |
| <STRONG>scanf(3)</STRONG>. |
| |
| |
| |
| <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(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-HISTORY">HISTORY</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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