curs_util(3x)
NAME
delay_output, filter, flushinp, getwin, key_name, keyname, nofilter,
putwin, unctrl, use_env, wunctrl - miscellaneous curses utility
routines
SYNOPSIS
#include <curses.h> char *unctrl(chtype c); char *wunctrl(cchar_t *c); char *keyname(int c); char *key_name(wchar_t w); void filter(void); void nofilter(void); void use_env(bool f); int putwin(WINDOW *win, FILE *filep); WINDOW *getwin(FILE *filep); int delay_output(int ms); int flushinp(void);
DESCRIPTION
The unctrl routine returns a character string which is a printable representation of the character c, ignoring attributes. Control characters are displayed in the ^X notation. Printing characters are displayed as is. The corresponding wunctrl returns a printable representation of a wide-character.
The keyname routine returns a character string corresponding to the key
c. Control characters are displayed in the ^X notation. Values above
128 are either meta characters, shown in the M-X notation, or the names
of function keys, or null. The corresponding key_name returns a character string corresponding to the wide-character value w. The two
functions do not return the same set of strings; the latter returns
null where the former would display a meta character.
The filter routine, if used, must be called before initscr or newterm
are called. The effect is that, during those calls, LINES is set to 1;
the capabilities clear, cup, cud, cud1, cuu1, cuu, vpa are disabled;
and the home string is set to the value of cr.
The nofilter routine cancels the effect of a preceding filter call. That allows the caller to initialize a screen on a different device, using a different value of $TERM. The limitation arises because the filter routine modifies the in-memory copy of the terminal information.
The use_env routine, if used, is called before initscr or newterm are
called. When called with FALSE as an argument, the values of lines and
columns specified in the terminfo database will be used, even if environment variables LINES and COLUMNS (used by default) are set, or if
curses is running in a window (in which case default behavior would be
to use the window size if LINES and COLUMNS are not set). Note that
setting LINES or COLUMNS overrides the corresponding size which may be
obtained from the operating system.
The putwin routine writes all data associated with window win into the
file to which filep points. This information can be later retrieved
using the getwin function.
The getwin routine reads window related data stored in the file by
putwin. The routine then creates and initializes a new window using
that data. It returns a pointer to the new window.
The delay_output routine inserts an ms millisecond pause in output.
This routine should not be used extensively because padding characters
are used rather than a CPU pause. If no padding character is specified, this uses napms to perform the delay.
The flushinp routine throws away any typeahead that has been typed by
the user and has not yet been read by the program.
RETURN VALUE
Except for flushinp, routines that return an integer return ERR upon
failure and OK (SVr4 specifies only "an integer value other than ERR")
upon successful completion.
Routines that return pointers return NULL on error.
- X/Open does not define any error conditions. In this implementation
- flushinp
returns an error if the terminal was not initialized.
- putwin
returns an error if the associated fwrite calls return an error.
PORTABILITY
The XSI Curses standard, Issue 4 describes these functions. It states
that unctrl and wunctrl will return a null pointer if unsuccessful, but
does not define any error conditions.
The SVr4 documentation describes the action of filter only in the vaguest terms. The description here is adapted from the XSI Curses standard (which erroneously fails to describe the disabling of cuu).
The strings returned by unctrl in this implementation are determined at
compile time, showing C1 controls from the upper-128 codes with a `~'
prefix rather than `^'. Other implementations have different conventions. For example, they may show both sets of control characters with
`^', and strip the parameter to 7 bits. Or they may ignore C1 controls
and treat all of the upper-1280 codes as printable. This implementation uses 8 bits but does not modify the string to reflect locale. The
use_legacy_coding function allows the caller to change the output of
unctrl.
The keyname function may return the names of user-defined string capabilities which are defined in the terminfo entry via the -x option of
tic.
The nofilter routine is specific to ncurses. It was not supported on
Version 7, BSD or System V implementations. It is recommended that any
code depending on ncurses extensions be conditioned using NCURSES_VERSION.