---
name: "curs_refresh"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/curs_refresh"
---

# curs\_refresh(3)

refresh curses windows or lines thereupon

## NAME

**doupdate**, **redrawwin**, **refresh**, **wnoutrefresh**, **wredrawln**, **wrefresh** - refresh *curses* windows or lines thereupon

## SYNOPSIS

```
#include <curses.h>
```

**int refresh(void);** **int wrefresh(WINDOW \****win***);** **int wnoutrefresh(WINDOW \****win***);** **int doupdate(void);**

**int redrawwin(WINDOW \****win***);** **int wredrawln(WINDOW \****win***, int** *beg\_line***, int** *num\_lines***);**

## DESCRIPTION

### refresh, wrefresh

**The refresh and wrefresh routines (or wnoutrefresh and** **doupdate) must be called to get actual output to the terminal,** **as other routines merely manipulate data structures.** **The routine wrefresh copies** **the named window to the** *physical screen***,** **taking into account what is already there to do optimizations.** **The refresh routine is the** **same, using stdscr as the default window.** **Unless leaveok(3X) has been** **enabled, the physical cursor of the terminal is left at the location of the** **cursor for that window.**

### wnoutrefresh, doupdate

**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** *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,** **which copies the named window to the** *virtual screen***, and**

- •

  **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** *physical screen* **(i.e., 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 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 PORTABILITY below for a warning about** **exploiting this behavior.)**

### wredrawln, redrawwin

**The wredrawln routine indicates to curses 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).** **The routine redrawwin touches the entire window.**

## RETURN VALUE

**These routines return the integer ERR upon failure and OK**

**In this implementation**

- **wnoutrefresh**

  **returns** **ERR** **if the window pointer is null, or** **if the window is really a pad.**

- **wredrawln**

  **return** **ERR** **if the associated call to touchln returns** **ERR**.

## NOTES

**refresh** **and** **redrawwin** **may be implemented as macros.**

## PORTABILITY

**X/Open Curses Issue 4 describes these functions.** **It specifies no error conditions for them.**

**SVr4 describes a successful return value only as** **“an integer value other than** *ERR*”.

**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.**

## SEE ALSO

**curses(3X),** **curs\_outopts(3X),** **curs\_variables(3X)**