brlapi_protocol(3) Library Functions Manual brlapi_protocol(3)

brlapi_protocol - BrlAPI's protocol


- Instructions and constants for BrlAPI 's protocol.


struct brlapi_header_t
struct brlapi_versionPacket_t
struct brlapi_authClientPacket_t
struct brlapi_authServerPacket_t
struct brlapi_errorPacket_t
struct brlapi_getDriverSpecificModePacket_t
struct brlapi_writeArgumentsPacket_t
struct brlapi_paramValuePacket_t
struct brlapi_paramRequestPacket_t
union brlapi_packet_t


#define BRLAPI_PROTOCOL_VERSION ((uint32_t) 8) /** Communication protocol version */
#define BRLAPI_MAXPACKETSIZE 4096
#define BRLAPI_PACKET_VERSION 'v'
#define BRLAPI_PACKET_AUTH 'a'
#define BRLAPI_PACKET_GETDRIVERNAME 'n'
#define BRLAPI_PACKET_GETMODELID 'd'
#define BRLAPI_PACKET_GETDISPLAYSIZE 's'
#define BRLAPI_PACKET_ENTERTTYMODE 't'
#define BRLAPI_PACKET_SETFOCUS 'F'
#define BRLAPI_PACKET_LEAVETTYMODE 'L'
#define BRLAPI_PACKET_KEY 'k'
#define BRLAPI_PACKET_IGNOREKEYRANGES 'm'
#define BRLAPI_PACKET_ACCEPTKEYRANGES 'u'
#define BRLAPI_PACKET_WRITE 'w'
#define BRLAPI_PACKET_ENTERRAWMODE '*'
#define BRLAPI_PACKET_LEAVERAWMODE '#'
#define BRLAPI_PACKET_PACKET 'p'
#define BRLAPI_PACKET_ACK 'A'
#define BRLAPI_PACKET_ERROR 'e'
#define BRLAPI_PACKET_EXCEPTION 'E'
#define BRLAPI_PACKET_SUSPENDDRIVER 'S'
#define BRLAPI_PACKET_RESUMEDRIVER 'R'
#define BRLAPI_PACKET_SYNCHRONIZE 'Z'
#define BRLAPI_PACKET_PARAM_VALUE (('P'<<8) + 'V')
#define BRLAPI_PACKET_PARAM_REQUEST (('P'<<8) + 'R')
#define BRLAPI_PACKET_PARAM_UPDATE (('P'<<8) + 'U')
#define BRLAPI_DEVICE_MAGIC (0xdeadbeefL)
#define BRLAPI_HEADERSIZE sizeof(brlapi_header_t)
#define BRLAPI_AUTH_NONE 'N'
#define BRLAPI_AUTH_KEY 'K'
#define BRLAPI_AUTH_CRED 'C'
#define BRLAPI_WF_DISPLAYNUMBER 0X01
#define BRLAPI_WF_REGION 0X02
#define BRLAPI_WF_TEXT 0X04
#define BRLAPI_WF_ATTR_AND 0X08
#define BRLAPI_WF_ATTR_OR 0X10
#define BRLAPI_WF_CURSOR 0X20
#define BRLAPI_WF_CHARSET 0X40
#define BRLAPI_PVF_GLOBAL 0X01 /** Value is the global value */
#define BRLAPI_MAXPARAMSIZE (BRLAPI_MAXPACKETSIZE - (sizeof(uint32_t) + sizeof(brlapi_param_t) + 2*sizeof(uint32_t)))
#define BRLAPI_PARAMF_GET 0X100 /** Get current parameter value */
#define BRLAPI_PARAMF_SUBSCRIBE 0X200 /** Subscribe to parameter updates */
#define BRLAPI_PARAMF_UNSUBSCRIBE 0X400 /** Unsubscribe from parameter updates */


ssize_t brlapi_writePacket (brlapi_fileDescriptor fd, brlapi_packetType_t type, const void *buf, size_t size)
ssize_t brlapi_readPacketHeader (brlapi_fileDescriptor fd, brlapi_packetType_t *packetType)
ssize_t brlapi_readPacketContent (brlapi_fileDescriptor fd, size_t packetSize, void *buf, size_t bufSize)
ssize_t brlapi_readPacket (brlapi_fileDescriptor fd, brlapi_packetType_t *type, void *buf, size_t size)


pthread_mutex_t brlapi_fd_mutex

These are defines for the protocol between BrlAPI 's server and clients. Understanding is not needed to use the BrlAPI library, so reading this is not needed unless really wanting to connect to BrlAPI without BrlAPI 's library.

Explicit socket credentials authorization

Key authorization

No or implicit authorization

Magic number to give when sending a BRLPACKET_ENTERRAWMODE or BRLPACKET_SUSPEND packet

Size of packet headers

Maximum packet size for packets exchanged on sockets and with braille terminal

Unmask key ranges

Acknowledgement

Authorization

Enter in raw mode

Asks for a specified tty

non-fatal error

Exception

Dimensions of brl display

Ask which driver is used

Ask which model is used

Mask key ranges

Braille key

Leave raw mode

Release the tty

Raw packets

Parameter request

Parameter update

Parameter value

Resume driver

Set current tty focus

Suspend driver

Synchronize exceptions

Version

Write

Flags for parameter requests

Flags for parameter values

And attributes

Or attributes

Charset

Cursor position

Flags for writing Display number

Region parameter

Contains some text

Read a packet from BrlAPI server

This function is for internal use, but one might use it if one really knows what one is doing...

type is where the function will store the packet type; it should always be one of the above defined BRLPACKET_* (or else something very nasty must have happened :/).

The syntax is the same as read()'s.

Returns

packet's size, -2 if EOF occurred, -1 on error or signal interruption.

If the packet is larger than the supplied buffer, the buffer will be filled with the beginning of the packet, the rest of the packet being discarded. This follows the semantics of the recv system call when the MSG_TRUNC option is given.

See also

brlapi_writePacket()

Read the content of a packet from BrlAPI server

This function is for internal use, but one might use it if one really knows what one is doing...

packetSize is the size announced by brlapi_readPacketHeader()

bufSize is the size of buf

Returns

packetSize, -2 if EOF occurred, -1 on error.

If the packet is larger than the supplied buffer, the buffer will be filled with the beginning of the packet, the rest of the packet being discarded. This follows the semantics of the recv system call when the MSG_TRUNC option is given.

See also

brlapi_writePacket() brlapi_readPacketHeader() brlapi_readPacket()

Read the header (type+size) of a packet from BrlAPI server

This function is for internal use, but one might use it if one really knows what one is doing...

type is where the function will store the packet type; it should always be one of the above defined BRLPACKET_* (or else something very nasty must have happened :/).

Returns

packet's size, -2 if EOF occurred, -1 on error or signal interruption.

See also

brlapi_writePacket() brlapi_readPacketContent brlapi_readPacket

Send a packet to BrlAPI server

This function is for internal use, but one might use it if one really knows what one is doing...

type should only be one of the above defined BRLPACKET_*.

The syntax is the same as write()'s.

Returns

0 on success, -1 on failure.

See also

brlapi_readPacketHeader() brlapi_readPacketContent() brlapi_readPacket()

Mutex for protecting concurrent fd access

In order to regulate concurrent access to the library's file descriptor and requests to / answers from BrlAPI server, every function of the library locks this mutex, namely

  • brlapi_openConnection()
  • brlapi_closeConnection()
  • brlapi_enterRawMode()
  • brlapi_leaveRawMode()
  • brlapi_sendRaw()
  • brlapi_recvRaw()
  • brlapi_getDriverName()
  • brlapi_getDisplaySize()
  • brlapi_enterTtyMode()
  • brlapi_enterTtyModeWithPath()
  • brlapi_leaveTtyMode()
  • brlapi_*write*()
  • brlapi_(un)?ignorekey(Range|Set)()
  • brlapi_readKey()

If both these functions and brlapi_writePacket() or brlapi_readPacket() are used in a multithreaded application, this mutex must be locked before calling brlapi_writePacket() or brlapi_readPacket(), and unlocked afterwards.

Generated automatically by Doxygen for BrlAPI from the source code.

Version 0.8 BrlAPI