- The effect of get_wstr is as though a series of calls to get_wch(3x)
- were made, until a newline, other end-of-line, or end-of-file condition
- is processed. An end-of-file condition is represented by WEOF, as de-
- fined in <wchar.h>. The newline and end-of-line conditions are repre-
- sented by the \nwchar_t value. In all instances, the end of the
- string is terminated by a null wchar_t. The routine places resulting
- values in the area pointed to by wstr.
-
- The user's erase and kill characters are interpreted. If keypad mode
- is on for the window, KEY_LEFT and KEY_BACKSPACE are both considered
- equivalent to the user's kill character.
-
- Characters input are echoed only if echo is currently on. In that
- case, backspace is echoed as deletion of the previous character (typi-
- cally a left motion).
+ The function wgetn_wstr is equivalent to a series of calls to
+ wget_wch(3x) until a newline or carriage return terminates the series:
+
+ o The terminating character is not included in the returned string.
+
+ o An end-of-file condition is represented by WEOF, as defined in
+ <wchar.h>.
+
+ o In all instances, the end of the string is terminated by a null
+ wchar_t.
+
+ o The function stores the result in the area pointed to by the wstr
+ parameter.
+
+ o The function reads at most n 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 erase and kill characters are interpreted:
+
+ o The erase character (e.g., ^H) erases the character at the end of
+ the buffer, moving the cursor to the left.
- The effect of wget_wstr is as though a series of calls to wget_wch were
- made.
+ If keypad mode is on for the window, KEY_LEFT and KEY_BACKSPACE are
+ both considered equivalent to the user's erase character.
- The effect of mvget_wstr is as though a call to move and then a series
- of calls to get_wch were made.
+ o The kill character (e.g., ^U) erases the entire buffer, leaving the
+ cursor at the beginning of the buffer.
- The effect of mvwget_wstr is as though a call to wmove and then a se-
- ries of calls to wget_wch were made.
+ Characters input are echoed only if echo is currently on. In that
+ case, backspace is echoed as deletion of the previous character (typi-
+ cally a left motion).
The getn_wstr, mvgetn_wstr, mvwgetn_wstr, and wgetn_wstr functions are
identical to the get_wstr, mvget_wstr, mvwget_wstr, and wget_wstr func-
@@ -97,25 +111,30 @@
+ Any of these functions other than wgetn_wstr may be macros.
+
Using get_wstr, mvget_wstr, mvwget_wstr, or wget_wstr to read a line
that overflows the array pointed to by wstr causes undefined results.
The use of getn_wstr, mvgetn_wstr, mvwgetn_wstr, or wgetn_wstr, respec-
tively, is recommended.
These functions cannot return KEY_ values because there is no way to
- distinguish a KEY_ value from a valid wchar_t value.
-
- All of these routines except wgetn_wstr may be macros.
+ distinguish a KEY_ value from a valid wchar_t value. may be macros.
- All of these functions return OK upon successful completion. Other-
- wise, they return ERR.
+ All of these functions return the integer OK upon successful comple-
+ tion. If unsuccessful, they return ERR.
+
+ X/Open defines no error conditions.
+
+ In this implementation, these functions return an error
+
+ o if the window pointer is null,
- Functions using a window parameter return an error if it is null.
+ o if its timeout expires without having any data, or
- wgetn_wstr
- returns an error if the associated call to wget_wch failed.
+ o if the associated call to wget_wch failed.
Functions with a "mv" prefix first perform a cursor movement using
wmove, and return an error if the position is outside the window, or if
@@ -124,22 +143,42 @@
These functions are described in The Single Unix Specification, Version
- 2. No error conditions are defined. This implementation returns ERR
- if the window pointer is null, or if the lower-level wget_wch call re-
- turns an ERR. In the latter case, an ERR return without other data is
- treated as an end-of-file condition, and the returned array contains a
- WEOF followed by a null wchar_t.
+ 2. No error conditions are defined.
+
+ This implementation returns ERR if the window pointer is null, or if
+ the lower-level wget_wch call returns an ERR. In the latter case, an
+ ERR return without other data is treated as an end-of-file condition,
+ and the returned array contains a WEOF followed by a null wchar_t.
X/Open curses documented these functions to pass an array of wchar_t in
1997, but that was an error because of this part of the description:
- The effect of get_wstr() is as though a series of calls to
- get_wch() were made, until a newline character, end-of-line
- character, or end-of-file character is processed.
+ The effect of get_wstr is as though a series of calls to get_wch
+ were made, until a newline character, end-of-line character, or
+ end-of-file character is processed.
+
+ The latter function get_wch can return a negative value, while wchar_t
+ is a unsigned type. All of the vendors implement this using wint_t,
+ following the standard.
+
+ X/Open Curses, Issue 7 (2009) is unclear regarding whether the termi-
+ nating nullwchar_t value is counted in the length parameter n. X/Open
+ Curses, Issue 7 revised the corresponding description of wgetnstr to
+ address this issue. The unrevised description of wget_nwstr can be in-
+ terpreted either way. This implementation counts the terminator in the
+ length.
+
+ X/Open Curses does not specify what happens if the length n is nega-
+ tive.
+
+ o For analogy with wgetnstr, ncurses 6.2 uses a limit (based on
+ LINE_MAX).
+
+ o Some other implementations (such as Solaris xcurses) do the same,
+ while others (PDCurses) do not allow this.
- The latter function get_wch() can return a negative value, while
- wchar_t is a unsigned type. All of the vendors implement this using
- wint_t, following the standard.
+ o NetBSD 7 curses imitates ncurses 6.1 in this regard, treating a -1
+ as an indefinite number of characters.