+ In this implementation, vw_scanw and vwscanw are equivalent, to support
+ legacy applications. However, the latter (vwscanw) is obsolete:
+
+ o The XSI Curses standard, Issue 4 described these functions, noting
+ that the function vwscanw is marked TO BE WITHDRAWN, and is to be
+ replaced by a function vw_scanw using the <stdarg.h> interface.
+
+ o The Single Unix Specification, Version 2 states that vw_scanw is
+ preferred to vwscanw since the latter requires including
+ <varargs.h>, which cannot be used in the same file as <stdarg.h>.
+ This implementation uses <stdarg.h> for both, because that header
+ is included in <curses.h>.
+
+ o X/Open Curses, Issue 5 (December 2007) marked vwscanw (along with
+ vwprintw and the termcap interface) as withdrawn.
+
+ Both XSI and The Single Unix Specification, Version 2 state that these
+ functions return ERR or OK.
+
+ o Since the underlying scanf(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.
+
+ o 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 vsscanf to scan the string, which returns EOF on error.
+
+ o Portable applications should only test if the return value is ERR,
+ since the OK 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.
+
+
While scanw 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
@@ -119,51 +157,13 @@
va_list definition requires <stdarg.h>.
-
- In this implementation, vw_scanw and vwscanw are equivalent, to support
- legacy applications. However, the latter (vwscanw) is obsolete:
-
- o The XSI Curses standard, Issue 4 described these functions, noting
- that the function vwscanw is marked TO BE WITHDRAWN, and is to be
- replaced by a function vw_scanw using the <stdarg.h> interface.
-
- o The Single Unix Specification, Version 2 states that vw_scanw is
- preferred to vwscanw since the latter requires including
- <varargs.h>, which cannot be used in the same file as <stdarg.h>.
- This implementation uses <stdarg.h> for both, because that header
- is included in <curses.h>.
-
- o X/Open Curses, Issue 5 (December 2007) marked vwscanw (along with
- vwprintw and the termcap interface) as withdrawn.
-
- Both XSI and The Single Unix Specification, Version 2 state that these
- functions return ERR or OK.
-
- o Since the underlying scanf(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.
-
- o 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 vsscanf to scan the string, which returns EOF on error.
-
- o Portable applications should only test if the return value is ERR,
- since the OK 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.
-
-