curs_pad(3X) curs_pad(3X)
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 refreshes of pads (e.g., from scrolling or echoing of input) do not occur. 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. Unlike 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 rectan-gle rectangle
gle to be displayed on the screen. The lower right-hand corner of the rectangle to be displayed 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, pminrow,
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 noncontrol
control characters, a considerable performance 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 pechochar. 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
prefresh.
RETURN VALUE
Routines that return an integer return ERR upon failure and OK (SVr4 only specifies "an integer value
other than ERR") upon successful completion.
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 extends 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 we-cho_wchar wecho_wchar
cho_wchar returns an error.
NOTES
Note that pechochar may be a macro.
PORTABILITY
The XSI Curses standard, Issue 4 describes these functions.
SEE ALSO
curses(3X), curs_refresh(3X), curs_touch(3X), curs_addch(3X).
curs_pad(3X)
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