attroff, wattroff, attron, wattron, attrset, wattrset, color_set,
   wcolor_set, standend, wstandend, standout, wstandout, attr_get,
   wattr_get, attr_off, wattr_off, attr_on, wattr_on, attr_set, wattr_set,
   chgat, wchgat, mvchgat, mvwchgat, PAIR_NUMBER - curses character and
   window attribute control routines


   #include <curses.h>
   int attroff(int attrs);
   int wattroff(WINDOW *win, int attrs);
   int attron(int attrs);
   int wattron(WINDOW *win, int attrs);
   int attrset(int attrs);
   int wattrset(WINDOW *win, int attrs);
   int color_set(short color_pair_number, void* opts);
   int wcolor_set(WINDOW *win, short color_pair_number,
         void* opts);
   int standend(void);
   int wstandend(WINDOW *win);
   int standout(void);
   int wstandout(WINDOW *win);
   int attr_get(attr_t *attrs, short *pair, void *opts);
   int wattr_get(WINDOW *win, attr_t *attrs, short *pair,
          void *opts);
   int attr_off(attr_t attrs, void *opts);
   int wattr_off(WINDOW *win, attr_t attrs, void *opts);
   int attr_on(attr_t attrs, void *opts);
   int wattr_on(WINDOW *win, attr_t attrs, void *opts);
   int attr_set(attr_t attrs, short pair, void *opts);
   int wattr_set(WINDOW *win, attr_t attrs, short pair, void *opts);
   int chgat(int n, attr_t attr, short color,
         const void *opts);
   int wchgat(WINDOW *win, int n, attr_t attr,
         short color, const void *opts);
   int mvchgat(int y, int x, int n, attr_t attr,
         short color, const void *opts);
   int mvwchgat(WINDOW *win, int y, int x, int n,
         attr_t attr, short color, const void *opts);


   These  routines  manipulate the current attributes of the named window.
   The current attributes of a window apply to  all  characters  that  are
   written  into  the window with waddch, waddstr and wprintw.  Attributes
   are a property of the character, and move with  the  character  through
   any  scrolling  and  insert/delete  line/character  operations.  To the
   extent possible, they are displayed as appropriate modifications to the
   graphic rendition of characters put on the screen.

   The  routine attrset sets the current attributes of the given window to
   attrs.  The routine attroff turns  off  the  named  attributes  without
   turning  any  other  attributes on or off.  The routine attron turns on
   the  named  attributes  without  affecting  any  others.   The  routine
   standout  is  the  same as attron(A_STANDOUT).  The routine standend is
   the same as attrset(A_NORMAL) or attrset(0), that is, it turns off  all

   The attrset and related routines do not affect the attributes used when
   erasing portions of the window.  See bkgd(3NCURSES) for functions which
   modify the attributes used for erasing and clearing.

   The  attrset routine is actually a legacy feature predating SVr4 curses
   but kept in X/Open Curses for the same reason that SVr4 curses kept it:
   compatibility.   The routine attr_set provides for passing a color-pair

   The remaining attr_* functions operate exactly like  the  corresponding
   attr*  functions, except that they take arguments of type attr_t rather
   than int.

   The routine color_set sets the current color of the given window to the
   foreground/background  combination  described by the color_pair_number.
   The parameter opts is reserved for future use, applications must supply
   a null pointer.

   The  routine wattr_get returns the current attribute and color pair for
   the given window; attr_get returns the current attribute and color pair
   for stdscr.

   There  is  no  corresponding attrget function as such in X/Open Curses,
   although ncurses provides getattrs (see curs_legacy(3X)).

   The  routine  chgat  changes  the  attributes  of  a  given  number  of
   characters  starting at the current cursor location of stdscr.  It does
   not update the cursor and does not perform wrapping.  A character count
   of  -1  or  greater  than  the  remaining  window width means to change
   attributes all the way to the end of  the  current  line.   The  wchgat
   function  generalizes  this to any window; the mvwchgat function does a
   cursor move before acting.  In these functions, the color argument is a
   color-pair   index   (as  in  the  first  argument  of  init_pair,  see
   color(3NCURSES)).  The opts argument is  not  presently  used,  but  is
   reserved for the future (leave it NULL).

   The following video attributes, defined in <curses.h>, can be passed to
   the routines attron, attroff, and attrset, or OR'd with the  characters
   passed to addch (see addch(3NCURSES)).

          Name            Description
          A_NORMAL        Normal display (no highlight)
          A_STANDOUT      Best highlighting mode of the terminal.
          A_UNDERLINE     Underlining
          A_REVERSE       Reverse video
          A_BLINK         Blinking
          A_DIM           Half bright
          A_BOLD          Extra bright or bold
          A_PROTECT       Protected mode
          A_INVIS         Invisible or blank mode
          A_ALTCHARSET    Alternate character set
          A_ITALIC        Italics (non-X/Open extension)
          A_CHARTEXT      Bit-mask to extract a character
          COLOR_PAIR(n)   Color-pair number n

   These  video  attributes are supported by attr_on and related functions
   (which also support the attributes recognized by attron, etc.):

          Name            Description
          WA_HORIZONTAL   Horizontal highlight
          WA_LEFT         Left highlight

          WA_LOW          Low highlight
          WA_RIGHT        Right highlight
          WA_TOP          Top highlight
          WA_VERTICAL     Vertical highlight

   For consistency

   The following macro is the reverse of COLOR_PAIR(n):

   PAIR_NUMBER(attrs) Returns the pair number associated
                      with the COLOR_PAIR(n) attribute.

   The return values of many of these routines are  not  meaningful  (they
   are  implemented  as macro-expanded assignments and simply return their
   argument).  The SVr4 manual page claims (falsely) that  these  routines
   always return 1.


   Note  that  attroff,  wattroff,  attron,  wattron,  attrset,  wattrset,
   standend and standout may be macros.

   COLOR_PAIR values can only be OR'd with attributes if the  pair  number
   is less than 256.  The alternate functions such as color_set can pass a
   color pair value directly.  However, ncurses ABI 4 and 5 simply OR this
   value  within  the  alternate functions.  You must use ncurses ABI 6 to
   support more than 256 color pairs.


   These functions are supported in the XSI Curses standard, Issue 4.  The
   standard  defined  the  dedicated type for highlights, attr_t, which is
   not defined in SVr4 curses.  The functions taking attr_t arguments  are
   not supported under SVr4.

   The  XSI  Curses standard states that whether the traditional functions
   attron/attroff/attrset can manipulate attributes  other  than  A_BLINK,
   A_BOLD,  A_DIM, A_REVERSE, A_STANDOUT, or A_UNDERLINE is "unspecified".
   Under this implementation as  well  as  SVr4  curses,  these  functions
   correctly  manipulate all other highlights (specifically, A_ALTCHARSET,

   This implementation provides the A_ITALIC attribute for terminals which
   have   the   enter_italics_mode  (sitm)  and  exit_italics_mode  (ritm)
   capabilities.  Italics are not mentioned in X/Open Curses.  Unlike  the
   other  video  attributes,  I_ITALIC  is unrelated to the set_attributes
   capabilities.   This   implementation   makes   the   assumption   that
   exit_attribute_mode may also reset italics.

   XSI  Curses  added  the  new entry points, attr_get, attr_on, attr_off,
   attr_set,  wattr_on,  wattr_off,  wattr_get,  wattr_set.    These   are
   intended  to  work  with a new series of highlight macros prefixed with
   WA_.  The older macros have direct counterparts in  the  newer  set  of

          Name            Description
          WA_NORMAL       Normal display (no highlight)
          WA_STANDOUT     Best highlighting mode of the terminal.
          WA_UNDERLINE    Underlining
          WA_REVERSE      Reverse video
          WA_BLINK        Blinking
          WA_DIM          Half bright
          WA_BOLD         Extra bright or bold
          WA_ALTCHARSET   Alternate character set

   Very old versions of this library did not force an update of the screen
   when changing the attributes.  Use touchwin  to  force  the  screen  to
   match the updated attributes.

   The  XSI  curses  standard specifies that each pair of corresponding A_
   and  WA_-using  functions  operates  on  the   same   current-highlight

   The  XSI  standard  extended  conformance  level  adds  new  highlights
   corresponding  WA_  macros  for  each).   As  of  August 2013, no known
   terminal provides these highlights (i.e., via the sgr1 capability).


   All routines return the integer OK on success, or ERR on failure.

   X/Open does not define any error conditions.

   This implementation returns an error if the  window  pointer  is  null.
   The wcolor_set function returns an error if the color pair parameter is
   outside the range 0..COLOR_PAIRS-1.  This implementation also  provides
   getattrs for compatibility with older versions of curses.

   Functions  with  a  "mv"  prefix  first perform a cursor movement using
   wmove, and return an error if the position is outside the window, or if
   the window pointer is null.


   ncurses(3NCURSES), addch(3NCURSES), addstr(3NCURSES), bkgd(3NCURSES),
   printw(3NCURSES), curses_variables(3NCURSES)



Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.