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| <TITLE>curs_refresh 3x</TITLE> | |
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| <H1>curs_refresh 3x</H1> | |
| <HR> | |
| <PRE> | |
| <!-- Manpage converted by man2html 3.0.1 --> | |
| <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG> <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG> | |
| </PRE> | |
| <H2>NAME</H2><PRE> | |
| <STRONG>doupdate</STRONG>, <STRONG>redrawwin</STRONG>, <STRONG>refresh</STRONG>, <STRONG>wnoutrefresh</STRONG>, <STRONG>wredrawln</STRONG>, | |
| <STRONG>wrefresh</STRONG> - refresh <STRONG>curses</STRONG> windows and lines | |
| </PRE> | |
| <H2>SYNOPSIS</H2><PRE> | |
| <STRONG>#include</STRONG> <STRONG><curses.h></STRONG> | |
| <STRONG>int</STRONG> <STRONG>refresh(void);</STRONG> | |
| <STRONG>int</STRONG> <STRONG>wrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG> | |
| <STRONG>int</STRONG> <STRONG>wnoutrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG> | |
| <STRONG>int</STRONG> <STRONG>doupdate(void);</STRONG> | |
| <STRONG>int</STRONG> <STRONG>redrawwin(WINDOW</STRONG> <STRONG>*win);</STRONG> | |
| <STRONG>int</STRONG> <STRONG>wredrawln(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>beg_line,</STRONG> <STRONG>int</STRONG> <STRONG>num_lines);</STRONG> | |
| </PRE> | |
| <H2>DESCRIPTION</H2><PRE> | |
| The <STRONG>refresh</STRONG> and <STRONG>wrefresh</STRONG> routines (or <STRONG>wnoutrefresh</STRONG> and | |
| <STRONG>doupdate</STRONG>) must be called to get actual output to the ter- | |
| minal, as other routines merely manipulate data struc- | |
| tures. The routine <STRONG>wrefresh</STRONG> copies the named window to | |
| the physical terminal screen, taking into account what is | |
| already there to do optimizations. The <STRONG>refresh</STRONG> routine is | |
| the same, using <STRONG>stdscr</STRONG> as the default window. Unless | |
| <STRONG>leaveok</STRONG> has been enabled, the physical cursor of the ter- | |
| minal is left at the location of the cursor for that win- | |
| dow. | |
| The <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple up- | |
| dates with more efficiency than <STRONG>wrefresh</STRONG> alone. In addi- | |
| tion to all the window structures, <STRONG>curses</STRONG> 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 <STRONG>wrefresh</STRONG> works by first calling <STRONG>wnoutrefresh</STRONG>, | |
| which copies the named window to the virtual screen, and | |
| then calling <STRONG>doupdate</STRONG>, 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 se- | |
| ries of calls to <STRONG>wrefresh</STRONG> results in alternating calls to | |
| <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG>, causing several bursts of out- | |
| put to the screen. By first calling <STRONG>wnoutrefresh</STRONG> for each | |
| window, it is then possible to call <STRONG>doupdate</STRONG> once, result- | |
| ing in only one burst of output, with fewer total charac- | |
| ters transmitted and less CPU time used. If the <EM>win</EM> argu- | |
| ment to <STRONG>wrefresh</STRONG> is the global variable <STRONG>curscr</STRONG>, 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 | |
| <EM>touched</EM> (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 <STRONG>PORTABILITY</STRONG> below for a warning about | |
| exploiting this behavior.) | |
| The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> 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 <STRONG>redrawwin</STRONG>() | |
| touches the entire window. | |
| </PRE> | |
| <H2>RETURN VALUE</H2><PRE> | |
| Routines that return an integer return <STRONG>ERR</STRONG> upon failure, | |
| and <STRONG>OK</STRONG> (SVr4 only specifies "an integer value other than | |
| <STRONG>ERR</STRONG>") upon successful completion. | |
| X/Open does not define any error conditions. In this im- | |
| plementation | |
| <STRONG>wnoutrefresh</STRONG> | |
| returns an error if the window pointer is | |
| null, or if the window is really a pad. | |
| <STRONG>wredrawln</STRONG> | |
| returns an error if the associated call to | |
| <STRONG>touchln</STRONG> returns an error. | |
| </PRE> | |
| <H2>NOTES</H2><PRE> | |
| Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros. | |
| </PRE> | |
| <H2>PORTABILITY</H2><PRE> | |
| The XSI Curses standard, Issue 4 describes these func- | |
| tions. | |
| Whether <STRONG>wnoutrefresh()</STRONG> 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 ex- | |
| plicit <STRONG>touchwin()</STRONG> before the <STRONG>wnoutrefresh()</STRONG> call to guar- | |
| antee an entire-contents copy anywhere. | |
| </PRE> | |
| <H2>SEE ALSO</H2><PRE> | |
| <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG> | |
| <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG> | |
| </PRE> | |
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