pad(3NCURSES)pad(3NCURSES)NAME
newpad, subpad, prefresh, pnoutrefresh, pechochar, pecho_wchar - create
and display curses pads
SYNOPSIS
#include <curses.h>
WINDOW *newpad(int nlines, int ncols);
WINDOW *subpad(WINDOW *orig, int nlines, int ncols,
int begin_y, int begin_x);
int prefresh(WINDOW *pad, int pminrow, int pmincol,
int sminrow, int smincol, int smaxrow, int smaxcol);
int pnoutrefresh(WINDOW *pad, int pminrow, int pmincol,
int sminrow, int smincol, int smaxrow, int smaxcol);
int pechochar(WINDOW *pad, chtype ch);
int pecho_wchar(WINDOW *pad, const cchar_t *wch);
DESCRIPTION
The newpad routine creates and returns a pointer to a new pad data
structure with the given number of lines, nlines, and columns, ncols.
A pad is like a window, except that it is not restricted by the screen
size, and is not necessarily associated with a particular part of the
screen. Pads can be used when a large window is needed, and only a
part of the window will be on the screen at one time. Automatic re‐
freshes of pads (e.g., from scrolling or echoing of input) do not oc‐
cur. It is not legal to call wrefresh with a pad as an argument; the
routines prefresh or pnoutrefresh should be called instead. Note that
these routines require additional parameters to specify the part of the
pad to be displayed and the location on the screen to be used for the
display.
The subpad routine creates and returns a pointer to a subwindow within
a pad with the given number of lines, nlines, and columns, ncols. Un‐
like subwin, which uses screen coordinates, the window is at position
(begin_x, begin_y) on the pad. The window is made in the middle of the
window orig, so that changes made to one window affect both windows.
During the use of this routine, it will often be necessary to call
touchwin or touchline on orig before calling prefresh.
The prefresh and pnoutrefresh routines are analogous to wrefresh and
wnoutrefresh except that they relate to pads instead of windows. The
additional parameters are needed to indicate what part of the pad and
screen are involved. pminrow and pmincol specify the upper left-hand
corner of the rectangle to be displayed in the pad. sminrow, smincol,
smaxrow, and smaxcol specify the edges of the rectangle to be displayed
on the screen. The lower right-hand corner of the rectangle to be dis‐
played in the pad is calculated from the screen coordinates, since the
rectangles must be the same size. Both rectangles must be entirely
contained within their respective structures. Negative values of pmin‐
row, pmincol, sminrow, or smincol are treated as if they were zero.
The pechochar routine is functionally equivalent to a call to addch
followed by a call to refresh, a call to waddch followed by a call to
wrefresh, or a call to waddch followed by a call to prefresh. The
knowledge that only a single character is being output is taken into
consideration and, for non-control characters, a considerable perfor‐
mance gain might be seen by using these routines instead of their
equivalents. In the case of pechochar, the last location of the pad on
the screen is reused for the arguments to prefresh.
The pecho_wchar function is the analogous wide-character form of pe‐
chochar. It outputs one character to a pad and immediately refreshes
the pad. It does this by a call to wadd_wch followed by a call to pre‐
fresh.
RETURN VALUE
Routines that return an integer return ERR upon failure and OK (SVr4
only specifies "an integer value other than ERR") upon successful com‐
pletion.
Routines that return pointers return NULL on error, and set errno to
ENOMEM.
X/Open does not define any error conditions. In this implementation
prefresh and pnoutrefresh
return an error if the window pointer is null, or if the
window is not really a pad or if the area to refresh ex‐
tends off-screen or if the minimum coordinates are greater
than the maximum.
pechochar
returns an error if the window is not really a pad, and the
associated call to wechochar returns an error.
pecho_wchar
returns an error if the window is not really a pad, and the
associated call to wecho_wchar returns an error.
NOTES
Note that pechochar may be a macro.
PORTABILITY
The XSI Curses standard, Issue 4 describes these functions.
SEE ALSOncurses(3NCURSES), refresh(3NCURSES), touch(3NCURSES), addch(3NCURSES).
pad(3NCURSES)
