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| .\" Copyright 2018-2019,2020 Thomas E. Dickey * |
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| .\" $Id: curs_scanw.3x,v 1.26 2020/02/02 23:34:34 tom Exp $ |
| .TH curs_scanw 3X "" |
| .ie \n(.g .ds `` \(lq |
| .el .ds `` `` |
| .ie \n(.g .ds '' \(rq |
| .el .ds '' '' |
| .de bP |
| .ie n .IP \(bu 4 |
| .el .IP \(bu 2 |
| .. |
| .SH NAME |
| \fBscanw\fR, |
| \fBwscanw\fR, |
| \fBmvscanw\fR, |
| \fBmvwscanw\fR, |
| \fBvwscanw\fR, \fBvw_scanw\fR \- convert formatted input from a \fBcurses\fR window |
| .SH SYNOPSIS |
| \fB#include <curses.h>\fR |
| .sp |
| \fBint scanw(const char *fmt, ...);\fR |
| .br |
| \fBint wscanw(WINDOW *win, const char *fmt, ...);\fR |
| .br |
| \fBint mvscanw(int y, int x, const char *fmt, ...);\fR |
| .br |
| \fBint mvwscanw(WINDOW *win, int y, int x, const char *fmt, ...);\fR |
| .br |
| \fBint vw_scanw(WINDOW *win, const char *fmt, va_list varglist);\fR |
| .sp |
| /* obsolete */ |
| .br |
| \fBint vwscanw(WINDOW *win, const char *fmt, va_list varglist);\fR |
| .SH DESCRIPTION |
| The \fBscanw\fR, \fBwscanw\fR and \fBmvscanw\fR routines are analogous to |
| \fBscanf\fR [see \fBscanf\fR(3)]. |
| The effect of these routines is as though |
| \fBwgetstr\fR were called on the window, and the resulting line used as input |
| for \fBsscanf\fR(3). |
| Fields which do not map to a variable in the \fIfmt\fR |
| field are lost. |
| .PP |
| The \fBvwscanw\fR and \fBvw_scanw\fR routines are analogous to \fBvscanf\fR(3). |
| They perform a \fBwscanw\fR using a variable argument list. |
| The third argument is a \fIva_list\fR, |
| a pointer to a list of arguments, as defined in \fB<stdarg.h>\fR. |
| .SH RETURN VALUE |
| \fBvwscanw\fR returns \fBERR\fR on failure and an integer equal to the |
| number of fields scanned on success. |
| .PP |
| Applications may use the return value from the \fBscanw\fR, \fBwscanw\fR, |
| \fBmvscanw\fR and \fBmvwscanw\fR routines to determine the number of fields |
| which were mapped in the call. |
| .PP |
| Functions with a \*(``mv\*('' prefix first perform a cursor movement using |
| \fBwmove\fP, and return an error if the position is outside the window, |
| or if the window pointer is null. |
| .SH PORTABILITY |
| In this implementation, \fBvw_scanw\fP and \fBvwscanw\fP are equivalent, |
| to support legacy applications. |
| However, the latter (\fBvwscanw\fP) is obsolete: |
| .bP |
| The XSI Curses standard, Issue 4 described these functions, |
| noting that the function |
| \fBvwscanw\fR is marked TO BE WITHDRAWN, and is to be replaced by a function |
| \fBvw_scanw\fR using the \fB<stdarg.h>\fR interface. |
| .bP |
| The Single Unix Specification, Version 2 states that |
| \fBvw_scanw\fR is preferred to \fBvwscanw\fR since the latter requires |
| including \fB<varargs.h>\fR, which |
| cannot be used in the same file as \fB<stdarg.h>\fR. |
| This implementation uses \fB<stdarg.h>\fR for both, because that header |
| is included in \fB<curses.h\fR>. |
| .bP |
| X/Open Curses, Issue 5 (December 2007) marked \fBvwscanw\fP (along with |
| \fBvwprintw\fP and the termcap interface) as withdrawn. |
| .LP |
| Both XSI and The Single Unix Specification, Version 2 state that these |
| functions return \fBERR\fP or \fBOK\fP. |
| .bP |
| Since the underlying \fBscanf\fR(3) 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. |
| .bP |
| 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 \fBvsscanf\fP to scan the string, |
| which returns \fBEOF\fP on error. |
| .bP |
| Portable applications should only test if the return value is \fBERR\fP, |
| since the \fBOK\fP value (zero) is likely to be misleading. |
| .IP |
| 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. |
| .SH SEE ALSO |
| .na |
| \fBcurses\fR(3X), |
| \fBcurs_getstr\fR(3X), |
| \fBcurs_printw\fR(3X), |
| \fBcurs_termcap\fP(3X), |
| \fBscanf\fR(3). |