- The refresh and wrefresh routines (or wnoutrefresh and
- doupdate) must be called to get actual output to the ter-
+ The refresh and wrefresh routines (or wnoutrefresh and
+ doupdate) must be called to get actual output to the ter-
minal, as other routines merely manipulate data struc-
- tures. The routine wrefresh copies the named window to
+ tures. The routine wrefresh copies the named window to
the physical terminal screen, taking into account what is
- already there in order to do optimizations. The refresh
- routine is the same, using stdscr as the default window.
- Unless leaveok has been enabled, the physical cursor of
- the terminal is left at the location of the cursor for
- that window.
-
- The wnoutrefresh and doupdate routines allow multiple
- updates with more efficiency than wrefresh alone. In
- addition to all the window structures, curses keeps two
- data structures representing the terminal screen: a physi-
- cal screen, describing what is actually on the screen, and
- a virtual screen, describing what the programmer wants to
+ already there to do optimizations. The refresh routine is
+ the same, using stdscr as the default window. Unless
+ leaveok has been enabled, the physical cursor of the ter-
+ minal is left at the location of the cursor for that win-
+ dow.
+
+ The wnoutrefresh and doupdate routines allow multiple up-
+ dates with more efficiency than wrefresh alone. In addi-
+ tion to all the window structures, curses keeps two data
+ structures representing the terminal screen: a physical
+ screen, describing what is actually on the screen, and a
+ virtual screen, describing what the programmer wants to
have on the screen.
- The routine wrefresh works by first calling wnoutrefresh,
+ The routine wrefresh works by first calling wnoutrefresh,
which copies the named window to the virtual screen, and
- then calling doupdate, which compares the virtual screen
+ then calling doupdate, which compares the virtual screen
to the physical screen and does the actual update. If the
- programmer wishes to output several windows at once, a
- series of calls to wrefresh results in alternating calls
- to wnoutrefresh and doupdate, causing several bursts of
- output to the screen. By first calling wnoutrefresh for
- each window, it is then possible to call doupdate once,
- resulting in only one burst of output, with fewer total
- characters transmitted and less CPU time used. If the win
- argument to wrefresh is the global variable curscr, the
- screen is immediately cleared and repainted from scratch.
+ programmer wishes to output several windows at once, a se-
+ ries of calls to wrefresh results in alternating calls to
+ wnoutrefresh and doupdate, causing several bursts of out-
+ put to the screen. By first calling wnoutrefresh for each
+ window, it is then possible to call doupdate once, result-
+ ing in only one burst of output, with fewer total charac-
+ ters transmitted and less CPU time used. If the win argu-
+ ment to wrefresh is the global variable curscr, the screen
+ is immediately cleared and repainted from scratch.
The phrase "copies the named window to the virtual screen"
- above is ambiguous. What actually happens is that all
- touched (changed) lines in the window are copied to the
- virtual screen. This affects programs that use overlap-
- ping windows; it means that if two windows overlap, you
- can refresh them in either order and the overlap region
+ above is ambiguous. What actually happens is that all
+ touched (changed) lines in the window are copied to the
+ virtual screen. This affects programs that use overlap-
+ ping windows; it means that if two windows overlap, you
+ can refresh them in either order and the overlap region
will be modified only when it is explicitly changed. (But
- see the section on PORTABILITY below for a warning about
+ see the section on PORTABILITY below for a warning about
exploiting this behavior.)
- The wredrawln routine indicates to curses that some screen
- lines are corrupted and should be thrown away before any-
- thing is written over them. It touches the indicated
- lines (marking them changed). The routine redrawwin()
+ The wredrawln routine indicates to curses that some screen
+ lines are corrupted and should be thrown away before any-
+ thing is written over them. It touches the indicated
+ lines (marking them changed). The routine redrawwin()
touches the entire window.
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 an integer return ERR upon failure,
+ and OK (SVr4 only specifies "an integer value other than
+ ERR") upon successful completion.
+
+ X/Open does not define any error conditions. In this im-
+ plementation
+
+ wnoutrefresh
+ returns an error if the window pointer is
+ null, or if the window is really a pad.
+
+ wredrawln
+ returns an error if the associated call to
+ touchln returns an error.
NOTES
- Note that refresh and redrawwin may be macros.
+ Note that refresh and redrawwin may be macros.
@@ -90,40 +143,23 @@
The XSI Curses standard, Issue 4 describes these func-
tions.
- Whether wnoutrefresh() copies to the virtual screen the
+ Whether wnoutrefresh() copies to the virtual screen the
entire contents of a window or just its changed portions
has never been well-documented in historic curses versions
(including SVr4). It might be unwise to rely on either
behavior in programs that might have to be linked with
- other curses implementations. Instead, you can do an
- explicit touchwin() before the wnoutrefresh() call to
- guarantee an entire-contents copy anywhere.
+ other curses implementations. Instead, you can do an ex-
+ plicit touchwin() before the wnoutrefresh() call to guar-
+ antee an entire-contents copy anywhere.