brlapi__readKey - Reading key presses - How to read key presses from the braille terminal.
Data Structures
struct brlapi_expandedKeyCode_t
struct brlapi_describedKeyCode_t
struct brlapi_range_t
Macros
#define brlapi_ignoreAllKeys()
brlapi_ignoreKeys(brlapi_rangeType_all, NULL, 0)
#define brlapi_acceptAllKeys()
brlapi_acceptKeys(brlapi_rangeType_all, NULL, 0)
#define BRLAPI_UC_ROW 0x2800UL
#define brlapi__ignoreAllKeys(handle) brlapi__ignoreKeys(handle,
brlapi_rangeType_all, NULL, 0)
#define brlapi__acceptAllKeys(handle) brlapi__acceptKeys(handle,
brlapi_rangeType_all, NULL, 0)
Enumerations
enum brlapi_rangeType_t { brlapi_rangeType_all, brlapi_rangeType_type,
brlapi_rangeType_command, brlapi_rangeType_key,
brlapi_rangeType_code }
Functions
int BRLAPI_STDCALL brlapi_expandKeyCode (brlapi_keyCode_t code,
brlapi_expandedKeyCode_t *expansion)
int BRLAPI_STDCALL brlapi_describeKeyCode (brlapi_keyCode_t code,
brlapi_describedKeyCode_t *description)
int BRLAPI_STDCALL brlapi_readKey (int wait, brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi__readKey (brlapi_handle_t *handle, int wait,
brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi_readKeyWithTimeout (int timeout_ms,
brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi__readKeyWithTimeout (brlapi_handle_t *handle,
int timeout_ms, brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi_ignoreKeys (brlapi_rangeType_t type, const
brlapi_keyCode_t keys[], unsigned int count)
int BRLAPI_STDCALL brlapi__ignoreKeys (brlapi_handle_t *handle,
brlapi_rangeType_t type, const brlapi_keyCode_t keys[], unsigned
int count)
int BRLAPI_STDCALL brlapi_acceptKeys (brlapi_rangeType_t type, const
brlapi_keyCode_t keys[], unsigned int count)
int BRLAPI_STDCALL brlapi__acceptKeys (brlapi_handle_t *handle,
brlapi_rangeType_t type, const brlapi_keyCode_t keys[], unsigned
int count)
int BRLAPI_STDCALL brlapi__ignoreAllKeys (brlapi_handle_t *handle)
int BRLAPI_STDCALL brlapi__acceptAllKeys (brlapi_handle_t *handle)
int BRLAPI_STDCALL brlapi_ignoreKeyRanges (const brlapi_range_t
ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi__ignoreKeyRanges (brlapi_handle_t *handle,
const brlapi_range_t ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi_acceptKeyRanges (const brlapi_range_t
ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi__acceptKeyRanges (brlapi_handle_t *handle,
const brlapi_range_t ranges[], unsigned int count)
brlapi_keys(3) BrlAPI brlapi_keys(3)
NAME
brlapi_keys - Reading key presses
- How to read key presses from the braille terminal.
SYNOPSIS
Data Structures
struct brlapi_expandedKeyCode_t
struct brlapi_describedKeyCode_t
struct brlapi_range_t
Macros
#define brlapi_ignoreAllKeys()
brlapi_ignoreKeys(brlapi_rangeType_all, NULL, 0)
#define brlapi_acceptAllKeys()
brlapi_acceptKeys(brlapi_rangeType_all, NULL, 0)
#define BRLAPI_UC_ROW 0x2800UL
#define brlapi__ignoreAllKeys(handle) brlapi__ignoreKeys(handle,
brlapi_rangeType_all, NULL, 0)
#define brlapi__acceptAllKeys(handle) brlapi__acceptKeys(handle,
brlapi_rangeType_all, NULL, 0)
Enumerations
enum brlapi_rangeType_t { brlapi_rangeType_all, brlapi_rangeType_type,
brlapi_rangeType_command, brlapi_rangeType_key,
brlapi_rangeType_code }
Functions
int BRLAPI_STDCALL brlapi_expandKeyCode (brlapi_keyCode_t code,
brlapi_expandedKeyCode_t *expansion)
int BRLAPI_STDCALL brlapi_describeKeyCode (brlapi_keyCode_t code,
brlapi_describedKeyCode_t *description)
int BRLAPI_STDCALL brlapi_readKey (int wait, brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi__readKey (brlapi_handle_t *handle, int wait,
brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi_readKeyWithTimeout (int timeout_ms,
brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi__readKeyWithTimeout (brlapi_handle_t *handle,
int timeout_ms, brlapi_keyCode_t *code)
int BRLAPI_STDCALL brlapi_ignoreKeys (brlapi_rangeType_t type, const
brlapi_keyCode_t keys[], unsigned int count)
int BRLAPI_STDCALL brlapi__ignoreKeys (brlapi_handle_t *handle,
brlapi_rangeType_t type, const brlapi_keyCode_t keys[], unsigned
int count)
int BRLAPI_STDCALL brlapi_acceptKeys (brlapi_rangeType_t type, const
brlapi_keyCode_t keys[], unsigned int count)
int BRLAPI_STDCALL brlapi__acceptKeys (brlapi_handle_t *handle,
brlapi_rangeType_t type, const brlapi_keyCode_t keys[], unsigned
int count)
int BRLAPI_STDCALL brlapi__ignoreAllKeys (brlapi_handle_t *handle)
int BRLAPI_STDCALL brlapi__acceptAllKeys (brlapi_handle_t *handle)
int BRLAPI_STDCALL brlapi_ignoreKeyRanges (const brlapi_range_t
ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi__ignoreKeyRanges (brlapi_handle_t *handle,
const brlapi_range_t ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi_acceptKeyRanges (const brlapi_range_t
ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi__acceptKeyRanges (brlapi_handle_t *handle,
const brlapi_range_t ranges[], unsigned int count)
Detailed Description
Once brlapi_enterTtyMode() has been called, the application can call
brlapi_readKey() to read key presses. Either key codes (see Types and
Defines forBrlAPI Key Codes) or commands will be returned, depending on
parameters given to brlapi_enterTtyMode().
Key presses are buffered, so that calling brlapi_readKey() in non-
blocking mode from time to time should suffice.
Macro Definition Documentation
#define brlapi__acceptAllKeys(handle) brlapi__acceptKeys(handle,
brlapi_rangeType_all, NULL, 0)
#define brlapi__ignoreAllKeys(handle) brlapi__ignoreKeys(handle,
brlapi_rangeType_all, NULL, 0)
int BRLAPI_STDCALL brlapi_acceptAllKeys(void)
brlapi_acceptKeys(brlapi_rangeType_all, NULL, 0)
Accept all key presses from the braille keyboard
This function asks the server to give all keys to the application, and
not give them to brltty.
Warning: after calling this function, make sure to call
brlapi_ignoreKeys() for ignoring important keys like
BRL_CMD_SWITCHVT_PREV/NEXT and such.
int BRLAPI_STDCALL brlapi_ignoreAllKeys(void)
brlapi_ignoreKeys(brlapi_rangeType_all, NULL, 0)
Ignore all key presses from the braille keyboard
This function asks the server to give all keys to brltty, rather than
returning them to the application via brlapi_readKey().
#define BRLAPI_UC_ROW 0x2800UL
Unicode braille row
Enumeration Type Documentation
enum brlapi_rangeType_t
types of key ranges
Enumerator
brlapi_rangeType_all
all keys, code must be 0
brlapi_rangeType_type
all keys of a given type
brlapi_rangeType_command
all keys of a given command block, i.e. matching the key type
and command parts
brlapi_rangeType_key
a given key with any flags
brlapi_rangeType_code
a given key code
Function Documentation
int BRLAPI_STDCALL brlapi__acceptAllKeys (brlapi_handle_t * handle)
int BRLAPI_STDCALL brlapi__acceptKeyRanges (brlapi_handle_t * handle, const
brlapi_range_t ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi__acceptKeys (brlapi_handle_t * handle,
brlapi_rangeType_t type, const brlapi_keyCode_t keys[], unsigned int
count)
int BRLAPI_STDCALL brlapi__ignoreAllKeys (brlapi_handle_t * handle)
int BRLAPI_STDCALL brlapi__ignoreKeyRanges (brlapi_handle_t * handle, const
brlapi_range_t ranges[], unsigned int count)
int BRLAPI_STDCALL brlapi__ignoreKeys (brlapi_handle_t * handle,
brlapi_rangeType_t type, const brlapi_keyCode_t keys[], unsigned int
count)
int BRLAPI_STDCALL brlapi__readKey (brlapi_handle_t * handle, int wait,
brlapi_keyCode_t * code)
int BRLAPI_STDCALL brlapi__readKeyWithTimeout (brlapi_handle_t * handle,
int timeout_ms, brlapi_keyCode_t * code)
int BRLAPI_STDCALL brlapi_acceptKeyRanges (const brlapi_range_t ranges[],
unsigned int count)
Accept some key presses from the braille keyboard
This function asks the server to return the provided key ranges
(inclusive) to the application, and not give them to brltty.
Parameters
ranges key ranges, which are inclusive
count number of ranges
Note
The given codes should be raw keycodes (i.e. some driver name was
given to brlapi_enterTtyMode())
int BRLAPI_STDCALL brlapi_acceptKeys (brlapi_rangeType_t type, const
brlapi_keyCode_t keys[], unsigned int count)
Accept some key presses from the braille keyboard
This function asks the server to give the provided keys to the
application, and not give them to brltty.
Parameters
type type of keys to be ignored
keys array of keys to be ignored
count number of keys
Note
The given codes should be brltty commands (NULL or '' was given to
brlapi_enterTtyMode())
int BRLAPI_STDCALL brlapi_describeKeyCode (brlapi_keyCode_t code,
brlapi_describedKeyCode_t * description)
Describe the components of a key code.
Parameters
code the keycode to be described
description pointer to the structure that receives the description
Returns
0 on success, -1 on error
int BRLAPI_STDCALL brlapi_expandKeyCode (brlapi_keyCode_t code,
brlapi_expandedKeyCode_t * expansion)
Expand the components of a key code
Parameters
code the key code to be expanded
expansion pointer to the structure that receives the components
Returns
0 on success, -1 on error
int BRLAPI_STDCALL brlapi_ignoreKeyRanges (const brlapi_range_t ranges[],
unsigned int count)
Ignore some key presses from the braille keyboard
This function asks the server to give the provided key ranges to
brltty, rather than returning them to the application via
brlapi_readKey().
Parameters
ranges key ranges, which are inclusive
count number of ranges
Note
The given codes should be raw keycodes (i.e. some driver name was
given to brlapi_enterTtyMode())
int BRLAPI_STDCALL brlapi_ignoreKeys (brlapi_rangeType_t type, const
brlapi_keyCode_t keys[], unsigned int count)
Ignore some key presses from the braille keyboard
This function asks the server to give the provided keys to brltty,
rather than returning them to the application via brlapi_readKey().
Parameters
type type of keys to be ignored
keys array of keys to be ignored
count number of keys
Note
The given codes should be brltty commands (NULL or '' was given to
brlapi_enterTtyMode())
int BRLAPI_STDCALL brlapi_readKey (int wait, brlapi_keyCode_t * code)
Read a key from the braille keyboard
This function returns one key press's code.
If NULL or '' was given to brlapi_enterTtyMode(), a brltty command is
returned, as described in the documentation for brlapi_keyCode_t . It
is hence pretty driver-independent, and should be used by default when
no other option is possible.
By default, all commands but those which restart drivers and switch
virtual terminals are returned to the application and not to brltty. If
the application doesn't want to see some command events, it should call
brlapi_ignoreKeys()
If some driver name was given to brlapi_enterTtyMode(), a raw keycode
is returned, as specified by the terminal driver, usually in
<brltty/brldefs-xy> where xy is the driver's code. It generally
corresponds to the very code that the terminal tells to the driver.
This should only be used by applications which are dedicated to a
particular braille terminal. Hence, checking the terminal type thanks
to a call to brlapi_getDriverName() before getting tty control is a
pretty good idea.
By default, all the keypresses will be passed to the client, none will
go through brltty, so the application will have to handle console
switching itself for instance.
Parameters
wait tells whether the call should block until a key is pressed (1)
or should only probe key presses (0);
code holds the key code if a key press is indeed read.
Returns
-1 on error or signal interrupt and *code is then undefined, 0 if
block was 0 and no key was pressed so far, or 1 and *code holds the
key code.
Programming hints:
If your application is only driven by braille command keypresses, you
can just call brlapi_readKey(1, &code) so that it keeps blocking,
waiting for keypresses.
Else, you'll probably want to use the file descriptor returned by
brlapi_openConnection() in your 'big polling loop'. For instance:
o in a select() loop, just add it to the readfds and exceptfds file
descriptor sets;
o in a gtk or atspi application, use g_io_add_watch(fileDescriptor,
G_IO_IN|G_IO_ERR|G_IO_HUP, f, data) for adding a callback called f;
o in an Xt/Xaw/motif-based application, use XtAppAddInput(app_context,
fileDescriptor, XtInputReadMask|XtInputExceptMask, f, data)
o etc.
and then, when you detect inbound trafic on the file descriptor, do
something like this:
while (brlapi_readKey(0, &code) { // process keycode code // ... }
The while loop is needed for processing all pending key presses, else
some of them may be left in libbrlapi's internal key buffer and you
wouldn't get them immediately.
Note
If the read is interrupted by a signal, brlapi_readKey() will
return -1, brlapi_errno will be BRLAPI_ERROR_LIBCERR and errno will
be EINTR.
int BRLAPI_STDCALL brlapi_readKeyWithTimeout (int timeout_ms,
brlapi_keyCode_t * code)
Read a key from the braille keyboard, unless a timeout expires
This function works like brlapi_readKey, except that parameter wait is
replaced by a timeout_ms parameter
Parameters
timeout_ms specifies how long the function should wait for a
keypress.
code holds the key code if a key press is indeed read.
If the timeout expires without any key being pressed, 0 is returned.
If timeout_ms is set to 0, this function looks for key events that have
been already received, but does not wait at all if no event was
received.
If timeout_ms is set to a negative value, this function behaves like
brlapi_readKey, i.e. it uses an infinite timeout.
Author
Generated automatically by Doxygen for BrlAPI from the source code.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------------------+
|Availability | library/accessibility/brltty |
+---------------+------------------------------+
|Stability | Pass-through volatile |
+---------------+------------------------------+
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
http://mielke.cc/brltty//archive/brltty-6.0.tar.xz.
Further information about this software can be found on the open source
community website at http://mielke.cc/brltty/.
Version 0.7 Mon Jun 27 2022 brlapi_keys(3)