brlapi_write(3)                     BrlAPI                     brlapi_write(3)



NAME
       brlapi_write - Write text to the braille display.


SYNOPSIS
   Data Structures
       struct brlapi_writeArguments_t

   Macros
       #define BRLAPI_DISPLAY_DEFAULT   -1
       #define BRLAPI_CURSOR_LEAVE   -1
       #define BRLAPI_CURSOR_OFF   0
       #define BRLAPI_WRITEARGUMENTS_INITIALIZER

   Functions
       int BRLAPI_STDCALL brlapi_writeText (int cursor, const char *text)
       int BRLAPI_STDCALL brlapi__writeText (brlapi_handle_t *handle, int
           cursor, const char *text)
       int BRLAPI_STDCALL brlapi_writeWText (int cursor, const wchar_t *text)
       int BRLAPI_STDCALL brlapi__writeWText (brlapi_handle_t *handle, int
           cursor, const wchar_t *text)
       int BRLAPI_STDCALL brlapi_writeDots (const unsigned char *dots)
       int BRLAPI_STDCALL brlapi__writeDots (brlapi_handle_t *handle, const
           unsigned char *dots)
       int BRLAPI_STDCALL brlapi_write (const brlapi_writeArguments_t
           *arguments)
       int BRLAPI_STDCALL brlapi__write (brlapi_handle_t *handle, const
           brlapi_writeArguments_t *arguments)

Detailed Description
       After brlapi_enterTtyMode() has been called, the application can call
       one of these functions to write things on the braille display.

       Note
           Be sure to call brlapi_enterTtyMode() before calling
           brlapi_write(), or else you'll get an error. This is particularly
           not always trivial when writing multithreaded applications.

           Dots are coded as described in ISO/TR 11548-1: a dot pattern is
           coded by a byte in which bit 0 is set iff dot 1 is up, bit 1 is set
           iff dot 2 is up, ... bit 7 is set iff dot 8 is up. This also
           corresponds to the low-order byte of the coding of unicode's
           braille row U+2800.

           Text is translated by the server one to one, by just using a simple
           wchar_t to pattern table, i.e. no contraction/expansion is
           performed, because the client would then have no way to know how
           wide the output would be and thus the quantity of text to feed. If
           contraction/expansion is desired, the client should perform it
           itself (e.g. thanks to liblouis or gnome-braille) and send the
           resulting dot patterns. This is actually exactly the same problem
           as font rendering on a graphical display: for better control,
           nowadays all font rasterization is performed on the client side,
           and mere pixmaps are sent to the X server.

           For braille displays with multiple lines, text will be wrapped over
           the lines.

Macro Definition Documentation
   #define BRLAPI_CURSOR_LEAVE   -1
       Do not change the cursor's state or position.

       See also
           brlapi_writeText() brlapi_write() brlapi_writeArguments_t

   #define BRLAPI_CURSOR_OFF   0
       Do not display the cursor.

       See also
           brlapi_writeText() brlapi_write() brlapi_writeArguments_t

   #define BRLAPI_DISPLAY_DEFAULT   -1
       Write to the default display on the braille device.

       See also
           brlapi_write() brlapi_writeArguments_t

   #define BRLAPI_WRITEARGUMENTS_INITIALIZER
       Value:

         {   .displayNumber = BRLAPI_DISPLAY_DEFAULT,   .regionBegin = 0,   .regionSize = 0,   .text = NULL,   .textSize = -1,   .andMask = NULL,   .orMask = NULL,   .cursor = BRLAPI_CURSOR_LEAVE,   .charset = NULL }
       Allows to initialize a structure of type brlapi_writeArguments_t * with
       default values: displayNumber = BRLAPI_DISPLAY_DEFAULT; (unspecified)
       regionBegin = regionSize = 0; (update the whole display, DEPRECATED and
       will be forbidden in next release. You must always express the region
       you wish to update) text = andMask = orMask = NULL; (no text, no
       attribute) cursor = BRLAPI_CURSOR_LEAVE; (don't touch cursor)

Function Documentation
   int BRLAPI_STDCALL brlapi__write (brlapi_handle_t * handle, const
       brlapi_writeArguments_t * arguments)
   int BRLAPI_STDCALL brlapi__writeDots (brlapi_handle_t * handle, const
       unsigned char * dots)
   int BRLAPI_STDCALL brlapi__writeText (brlapi_handle_t * handle, int cursor,
       const char * text)
   int BRLAPI_STDCALL brlapi__writeWText (brlapi_handle_t * handle, int
       cursor, const wchar_t * text)
   int BRLAPI_STDCALL brlapi_write (const brlapi_writeArguments_t * arguments)
       Update a specific region of the braille display and apply and/or masks

       Parameters
           arguments gives information necessary for the update

       regionBegin and regionSize must be filled for specifying which part of
       the display will be updated, as well as the size (in characters, not
       bytes) of the text, andMask and orMask members.

       If given, the 'text' field holds the text that will be displayed in the
       region. The char string must hold exactly as many characters as the
       region fields express. For multibyte text, this is the number of
       multibyte characters. Notably, combining and double-width characters
       count for 1.

       The actual length of the text in bytes may be specified thanks to
       textSize. If -1 is given, it will be computed thanks to strlen(), so
       'text' must then be a NUL-terminated string.

       The 'andMask' and 'orMask' masks, if present, are then applied on top
       of the text, one byte per character. This hence permits the
       superimposing of attributes over the text. For instance, setting an
       andMask mask full of BRLAPI_DOTS(1,1,1,1,1,1,0,0) will only keep
       (logical AND) dots 1-6, hence dropping dots 7 and 8. On the contrary,
       setting an orMask full of BRLAPI_DOT7|BRLAPI_DOT8 will add (logical OR)
       dots 7 and 8.

       The 'charset' field, if present, specifies the charset of the 'text'
       field. If it is '', the current locale's charset (if any) is assumed.
       Else, the 8-bit charset of the server is assumed.

       A special invocation is with an unmodified initialized structure: this
       clears the client's whole display, letting the display of other
       applications on the same tty or of applications 'under' the tty appear.
       See Concurrency management section of the BrlAPI documentation for more
       details.

       Returns
           0 on success, -1 on error.

   int BRLAPI_STDCALL brlapi_writeDots (const unsigned char * dots)
       Write the given dots array to the display

       Parameters
           dots points on an array of dot information, one per character. Its
           size must hence be the same as what brlapi_getDisplaySize()
           returns.

       Returns
           0 on success, -1 on error.

   int BRLAPI_STDCALL brlapi_writeText (int cursor, const char * text)
       Write the given \0-terminated string to the braille display

       If the string is too long, it is truncated. If it's too short, it is
       padded with spaces. The text is assumed to be in the current
       application locale charset set by setlocale(3) if it was called, or the
       locale charset from the application locale environment variables if
       setlocale(3) was not called.

       Parameters
           cursor gives the cursor position; if equal to BRLAPI_CURSOR_OFF, no
           cursor is shown at all; if cursor==BRLAPI_CURSOR_LEAVE, the cursor
           is left where it is
           text points to the string to be displayed.

       Returns
           0 on success, -1 on error.

   int BRLAPI_STDCALL brlapi_writeWText (int cursor, const wchar_t * text)
       Write the given \0-terminated unicode string to the braille display

       If the string is too long, it is truncated. If it's too short, it is
       padded with spaces.

       Parameters
           cursor gives the cursor position; if equal to BRLAPI_CURSOR_OFF, no
           cursor is shown at all; if cursor==BRLAPI_CURSOR_LEAVE, the cursor
           is left where it is
           text points to the string to be displayed.

       Returns
           0 on success, -1 on error.

Author
       Generated automatically by Doxygen for BrlAPI from the source code.



Version 0.8                     Tue Feb 17 2026                brlapi_write(3)
