cursrefresh(3X) cursrefresh(3X)

NAME
       ddoouuppddaattee, rreeddrraawwwwiinn, rreeffrreesshh, wwnnoouuttrreeffrreesshh, wwrreeddrraawwllnn, wwrreeffrreesshh -
       refresh ccuurrsseess windows and lines

SYNOPSIS
       ##iinncclluuddee <>

       iinntt rreeffrreesshh((vvooiidd));;
       iinntt wwrreeffrreesshh((WWIINNDDOOWW **wwiinn));;
       iinntt wwnnoouuttrreeffrreesshh((WWIINNDDOOWW **wwiinn));;
       iinntt ddoouuppddaattee((vvooiidd));;
       iinntt rreeddrraawwwwiinn((WWIINNDDOOWW **wwiinn));;
       iinntt wwrreeddrraawwllnn((WWIINNDDOOWW **wwiinn,, iinntt bbeegglliinnee,, iinntt nnuummlliinneess));;

DESCRIPTION
       The rreeffrreesshh and wwrreeffrreesshh routines (or wwnnoouuttrreeffrreesshh and  ddoouuppddaattee)  must
       be called to get actual output to the terminal, as other routines mere-
       ly manipulate data structures.  The routine wwrreeffrreesshh copies  the  named
       window to the physical terminal screen, taking into account what is al-
       ready there to do optimizations.  The rreeffrreesshh routine is the same,  us-
       ing ssttddssccrr as the default window.  Unless lleeaavveeookk has been enabled, the
       physical cursor of the terminal is left at the location of  the  cursor
       for that window.

       The wwnnoouuttrreeffrreesshh and ddoouuppddaattee routines allow multiple updates with more
       efficiency than wwrreeffrreesshh alone.  In addition to all the  window  struc-
       tures,  ccuurrsseess  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 wwrreeffrreesshh works by first calling wwnnoouuttrreeffrreesshh, which  copies
       the  named  window  to  the  virtual screen, and then calling ddoouuppddaattee,
       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 wwrreeffrreesshh results  in  alternating  calls  to
       wwnnoouuttrreeffrreesshh  and  ddoouuppddaattee,  causing  several  bursts of output to the
       screen.  By first calling wwnnoouuttrreeffrreesshh for each window, it is then pos-
       sible  to  call  ddoouuppddaattee  once, resulting in only one burst of output,
       with fewer total characters transmitted and less CPU time used.  If the
       win  argument  to wwrreeffrreesshh is the global variable ccuurrssccrr, the screen is
       immediately cleared and repainted from scratch.

       The phrase "copies the named window to the virtual screen" above is am-
       biguous.   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  modi-
       fied  only  when  it  is  explicitly  changed.  (But see the section on
       PPOORRTTAABBIILLIITTYY below for a warning about exploiting this behavior.)

       The wwrreeddrraawwllnn routine indicates to ccuurrsseess 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 rou-
       tine rreeddrraawwwwiinn() touches the entire window.

RREETTUURRNN VVAALLUUEE
       Routines  that  return an integer return EERRRR upon failure, and OOKK (SVr4
       only specifies "an integer value other than EERRRR") upon successful  com-
       pletion.

       X/Open does not define any error conditions.  In this implementation

              wwnnoouuttrreeffrreesshh
                   returns  an  error if the window pointer is null, or if the
                   window is really a pad.

              wwrreeddrraawwllnn
                   returns an error if the associated call to ttoouucchhllnn  returns
                   an error.

NNOOTTEESS
       Note that rreeffrreesshh and rreeddrraawwwwiinn may be macros.

PPOORRTTAABBIILLIITTYY
       The XSI Curses standard, Issue 4 describes these functions.

       Whether wwnnoouuttrreeffrreesshh(()) 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 ttoouucchh-
       wwiinn(()) before the wwnnoouuttrreeffrreesshh(()) call to  guarantee  an  entire-contents
       copy anywhere.

SEE ALSO
       ccuurrsseess(3X), ccuurrssoouuttooppttss(3X)



                                                              cursrefresh(3X)