brlapi_connection - Man Page

struct brlapi_connectionSettings_t
Settings structure for BrlAPI connection.

#define BRLAPI_SOCKETPORTNUM   4101
#define BRLAPI_SOCKETPORT   '4101'
#define BRLAPI_SOCKETPATH   '/var/lib/BrlAPI'
#define BRLAPI_ETCDIR   '/etc'
#define BRLAPI_AUTHKEYFILE   'brlapi.key'
#define BRLAPI_DEFAUTH_KEYFILE   'keyfile:' BRLAPI_ETCDIR '/' BRLAPI_AUTHKEYFILE
#define BRLAPI_DEFAUTH_POLKIT   ''
#define BRLAPI_DEFAUTH   BRLAPI_DEFAUTH_KEYFILE BRLAPI_DEFAUTH_POLKIT
#define BRLAPI_INVALID_FILE_DESCRIPTOR   -1
#define BRLAPI_SETTINGS_INITIALIZER   { NULL, NULL }

typedef int brlapi_fileDescriptor

brlapi_fileDescriptor BRLAPI_STDCALL brlapi_openConnection (const brlapi_connectionSettings_t *desiredSettings, brlapi_connectionSettings_t *actualSettings)
brlapi_fileDescriptor BRLAPI_STDCALL brlapi__openConnection (brlapi_handle_t *handle, const brlapi_connectionSettings_t *desiredSettings, brlapi_connectionSettings_t *actualSettings)
brlapi_fileDescriptor BRLAPI_STDCALL brlapi_getFileDescriptor (void)
brlapi_fileDescriptor BRLAPI_STDCALL brlapi__getFileDescriptor (brlapi_handle_t *handle)
void BRLAPI_STDCALL brlapi_closeConnection (void)
void BRLAPI_STDCALL brlapi__closeConnection (brlapi_handle_t *handle)

Default name of the file containing BrlAPI 's authorization key

This name is relative to BRLAPI_ETCDIR

Default authorization setting

brltty 's settings directory

This is where authorization key and driver-dependent key names are found for instance.

Invalid value for brlapi_fileDescriptor

This is returned by brlapi_getFileDescriptor() when the connection is closed.

Allows to initialize a structure of type brlapi_connectionSettings_t * with default values.

Default unix path on which connections to BrlAPI can be established

Default port number on which connections to BrlAPI can be established

OS-dependent file descriptor type

This is the type for file descriptors returned by brlapi_openConnection() and brlapi_getFileDescriptor().

Cleanly close the socket

This function locks until a closing acknowledgement is received from the server. The socket is then freed, so the file descriptor brlapi_openConnection() gave has no meaning any more

Return the file descriptor used by the BrlAPI connection

This allows to use it with select(), g_io_add_watch(), XtAppAddInput(), etc.

BRLAPI_INVALID_FILE_DESCRIPTOR is returned when the connection was closed.

Open a socket and connect it to BrlAPI 's server

This function first loads an authorization key as specified in settings. It then creates a TCP socket and connects it to the specified machine, on the specified port. It writes the authorization key on the socket and waits for acknowledgement.

Returns

the file descriptor, or BRLAPI_INVALID_FILE_DESCRIPTOR on error

Note

The file descriptor is returned in case the client wants to communicate with the server without using libbrlapi functions. If it uses them however, it won't have to pass the file descriptor later, since the library keeps a copy of it. But that also means that brlapi_openConnection() may be called several times, but libbrlapi functions will always work with the last call's descriptor

Example:

if (brlapi_openConnection(&settings,&settings)<0) {
 fprintf(stderr,"couldn't connect to BrlAPI at %s: %s\n",
  settings.host, brlapi_strerror(&brlapi_error));
 exit(1);
}

Errors:

BrlAPI might not be on this TCP port, the host name might not be resolvable, the authorization may fail,...

Parameters

desiredSettings this gives the desired connection parameters, as described in brlapi_connectionSettings_t. If NULL, defaults values are used, so that it is generally a good idea to give NULL as default, and only fill a brlapi_connectionSettings_t structure when the user gave parameters to the program for instance;
actualSettings if not NULL, parameters which were actually used are stored here, if the application ever needs them. Since they are constant strings, or come from a getenv call, these must not be freed by the application.

See also

brlapi_connectionSettings_t brlapi_writePacket() brlapi_readPacketHeader() brlapi_readPacketContent() brlapi_readPacket()