.TH curs_refresh 3X "" .SH NAME \fBrefresh\fR, \fBwrefresh\fR, \fBwnoutrefresh\fR, \fBdoupdate\fR, \fBredrawwin\fR, \fBwredrawln\fR - refresh \fBcurses\fR windows and lines .SH SYNOPSIS \fB#include <curses.h>\fR \fBint refresh(void);\fR .br \fBint wrefresh(WINDOW *win);\fR .br \fBint wnoutrefresh(WINDOW *win);\fR .br \fBint doupdate(void);\fR .br \fBint redrawwin(WINDOW *win);\fR .br \fBint wredrawln(WINDOW *win, int beg_line, int num_lines);\fR .br .SH DESCRIPTION The \fBrefresh\fR and \fBwrefresh\fR routines (or \fBwnoutrefresh\fR and \fBdoupdate\fR) must be called to get actual output to the terminal, as other routines merely manipulate data structures. The routine \fBwrefresh\fR copies the named window to the physical terminal screen, taking into account what is already there in order to do optimizations. The \fBrefresh\fR routine is the same, using \fBstdscr\fR as the default window. Unless \fBleaveok\fR has been enabled, the physical cursor of the terminal is left at the location of the cursor for that window. The \fBwnoutrefresh\fR and \fBdoupdate\fR routines allow multiple updates with more efficiency than \fBwrefresh\fR alone. In addition to all the window structures, \fBcurses\fR 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 \fBwrefresh\fR works by first calling \fBwnoutrefresh\fR, which copies the named window to the virtual screen, and then calling \fBdoupdate\fR, 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 \fBwrefresh\fR results in alternating calls to \fBwnoutrefresh\fR and \fBdoupdate\fR, causing several bursts of output to the screen. By first calling \fBwnoutrefresh\fR for each window, it is then possible to call \fBdoupdate\fR once, resulting in only one burst of output, with fewer total characters transmitted and less CPU time used. If the \fIwin\fR argument to \fBwrefresh\fR is the global variable \fBcurscr\fR, 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 \fItouched\fR (changed) lines in the window are copied to the virtual screen. This affects programs that use overlapping 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 \fBPORTABILITY\fR below for a warning about exploiting this behavior.) The \fBwredrawln\fR routine indicates to \fBcurses\fR that some screen lines are corrupted and should be thrown away before anything is written over them it touches the indicated lines (marking them changed) then does a refresh of the window. The routine \fBredrawwin\fR() touches the entire window and then refreshes it. .SH RETURN VALUE Routines that return an integer return \fBERR\fR upon failure, and \fBOK\fR (SVr4 only specifies "an integer value other than \fBERR\fR") upon successful completion. .SH NOTES Note that \fBrefresh\fR and \fBredrawwin\fR may be macros. .SH PORTABILITY The XSI Curses standard, Issue 4 describes these functions. Whether \fBwnoutrefresh()\fR 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 \fBtouchwin()\fR before the \fBwnoutrefresh()\fR call to guarantee an entire-contents copy anywhere. .SH SEE ALSO \fBcurses\fR(3X), \fBcurs_outopts\fR(3X) .\"# .\"# The following sets edit modes for GNU EMACS .\"# Local Variables: .\"# mode:nroff .\"# fill-column:79 .\"# End: