Low-level OSC API(3)

NAME
Low-level OSC API -

  Typedefs
typedef long double lo_hires
Type used to represent numerical values in conversions between OSC types.

  Functions
int lo_send_message (lo_address targ, const char *path, lo_message msg)
send a lo_message object to target targ
int lo_send_message_from (lo_address targ, lo_server serv, const char *path, lo_message msg)
send a lo_message object to target targ from address of serv
int lo_send_bundle (lo_address targ, lo_bundle b)
send a lo_bundle object to address targ
int lo_send_bundle_from (lo_address targ, lo_server serv, lo_bundle b)
send a lo_bundle object to address targ from address of serv
lo_message lo_message_new ()
Create a new lo_message object.
void lo_message_free (lo_message m)
Free memory allocated by lo_message_new and any subsequent lo_message_add*() calls.
int lo_message_add (lo_message m, const char *types,...)
Append a number of arguments to a message.
int lo_message_add_internal (lo_message m, const char *file, const int line, const char *types,...)
the real message_add function (don't call directly)
int lo_message_add_varargs (lo_message m, const char *types, va_list ap)
Append a varargs list to a message.
int lo_message_add_varargs_internal (lo_message m, const char *types, va_list ap, const char *file, const int line)
the real message_add_varargs function (don't call directly)
void lo_message_add_int32 (lo_message m, int32_t a)
Append a data item and typechar of the specified type to a message.
void lo_message_add_float (lo_message m, float a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_string (lo_message m, const char *a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_blob (lo_message m, lo_blob a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_int64 (lo_message m, int64_t a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_timetag (lo_message m, lo_timetag a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_double (lo_message m, double a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_symbol (lo_message m, const char *a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_char (lo_message m, char a)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_midi (lo_message m, uint8_t a[4])
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_true (lo_message m)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_false (lo_message m)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_nil (lo_message m)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
void lo_message_add_infinitum (lo_message m)
Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.
lo_address lo_message_get_source (lo_message m)
Returns the source (lo_address) of an incoming message.
char * lo_message_get_types (lo_message m)
Return the message type tag string.
int lo_message_get_argc (lo_message m)
Return the message argument count.
lo_arg ** lo_message_get_argv (lo_message m)
Return the message arguments. Do not free the returned data.
size_t lo_message_length (lo_message m, const char *path)
Return the length of a message in bytes.
void * lo_message_serialise (lo_message m, const char *path, void *to, size_t *size)
Serialise the lo_message object to an area of memory and return a pointer to the serialised form. Opposite of lo_message_deserialise().
lo_message lo_message_deserialise (void *data, size_t size, int *result)
Deserialise a raw OSC message and return a new lo_message object. Opposite of lo_message_serialise().
const char * lo_address_get_hostname (lo_address a)
Return the hostname of a lo_address object.
const char * lo_address_get_port (lo_address a)
Return the port/service name of a lo_address object.
int lo_address_get_protocol (lo_address a)
Return the protocol of a lo_address object.
char * lo_address_get_url (lo_address a)
Return a URL representing an OSC address.
void lo_address_set_ttl (lo_address t, int ttl)
Set the Time-to-Live value for a given target address.
int lo_address_get_ttl (lo_address t)
Get the Time-to-Live value for a given target address.
lo_bundle lo_bundle_new (lo_timetag tt)
Create a new bundle object.
void lo_bundle_add_message (lo_bundle b, const char *path, lo_message m)
Adds an OSC message to an existing bundle.
size_t lo_bundle_length (lo_bundle b)
Return the length of a bundle in bytes.
void * lo_bundle_serialise (lo_bundle b, void *to, size_t *size)
Serialise the bundle object to an area of memory and return a pointer to the serialised form.
void lo_bundle_free (lo_bundle b)
Frees the memory taken by a bundle object.
void lo_bundle_free_messages (lo_bundle b)
Frees the memory taken by a bundle object and messages in the bundle.
int lo_is_numerical_type (lo_type a)
return true if the type specified has a numerical value, such as LO_INT32, LO_FLOAT etc.
int lo_is_string_type (lo_type a)
return true if the type specified has a textual value, such as LO_STRING or LO_SYMBOL.
int lo_coerce (lo_type type_to, lo_arg *to, lo_type type_from, lo_arg *from)
attempt to convert one OSC type to another.
lo_hires lo_hires_val (lo_type type, lo_arg *p)
return the numerical value of the given argument with the maximum native system precision.
lo_server lo_server_new (const char *port, lo_err_handler err_h)
Create a new server instance.
lo_server lo_server_new_with_proto (const char *port, int proto, lo_err_handler err_h)
Create a new server instance, specifying protocol.
lo_server lo_server_new_multicast (const char *group, const char *port, lo_err_handler err_h)
Create a new server instance, and join a UDP multicast group.
void lo_server_free (lo_server s)
Free up memory used by the lo_server object.
int lo_server_recv_noblock (lo_server s, int timeout)
Look for an OSC message waiting to be received.
int lo_server_recv (lo_server s)
Block, waiting for an OSC message to be received.
lo_method lo_server_add_method (lo_server s, const char *path, const char *typespec, lo_method_handler h, void *user_data)
Add an OSC method to the specifed server.
void lo_server_del_method (lo_server s, const char *path, const char *typespec)
Delete an OSC method from the specifed server.
int lo_server_get_socket_fd (lo_server s)
Return the file descriptor of the server socket.
int lo_server_get_port (lo_server s)
Return the port number that the server has bound to.
int lo_server_get_protocol (lo_server s)
Return the protocol that the server is using.
char * lo_server_get_url (lo_server s)
Return an OSC URL that can be used to contact the server.
int lo_server_events_pending (lo_server s)
Return true if there are scheduled events (eg. from bundles) waiting to be dispatched by the server.
double lo_server_next_event_delay (lo_server s)
Return the time in seconds until the next scheduled event.
char * lo_url_get_protocol (const char *url)
Return the protocol portion of an OSC URL, eg. udp, tcp.
char * lo_url_get_hostname (const char *url)
Return the hostname portion of an OSC URL.
char * lo_url_get_port (const char *url)
Return the port portion of an OSC URL.
char * lo_url_get_path (const char *url)
Return the path portion of an OSC URL.
int lo_strsize (const char *s)
A function to calculate the amount of OSC message space required by a C char *.
uint32_t lo_blobsize (lo_blob b)
A function to calculate the amount of OSC message space required by a lo_blob object.
int lo_pattern_match (const char *str, const char *p)
Test a string against an OSC pattern glob.
int lo_send_internal (lo_address t, const char *file, const int line, const char *path, const char *types,...)
the real send function (don't call directly)
int lo_send_timestamped_internal (lo_address t, const char *file, const int line, lo_timetag ts, const char *path, const char *types,...)
the real send_timestamped function (don't call directly)
int lo_send_from_internal (lo_address targ, lo_server from, const char *file, const int line, const lo_timetag ts, const char *path, const char *types,...)
the real lo_send_from function (don't call directly)
double lo_timetag_diff (lo_timetag a, lo_timetag b)
Find the time difference between two timetags.
void lo_timetag_now (lo_timetag *t)
Return a timetag for the current time.

Detailed Description

Use these functions if you require more precices control over OSC message contruction or handling that what is provided in the high-level functions described in liblo.

Typedef Documentation

  typedef long double lo_hires

Type used to represent numerical values in conversions between OSC types.

Function Documentation

  const char* lo_address_get_hostname (lo_address a)

Return the hostname of a lo_address object.

Returned value most not be modified or free'd. Value will be a dotted quad, colon'd IPV6 address, or resolvable name.

  const char* lo_address_get_port (lo_address a)

Return the port/service name of a lo_address object.

Returned value most not be modified or free'd. Value will be a service name or ASCII representation of the port number.

  int lo_address_get_protocol (lo_address a)

Return the protocol of a lo_address object.

Returned value will be one of LO_UDP, LO_TCP or LO_UNIX.

  int lo_address_get_ttl (lo_address t)

Get the Time-to-Live value for a given target address.

Parameters:
    t An OSC address.

Returns:
    An integer specifying the scope of a multicast UDP message.

  char* lo_address_get_url (lo_address a)

Return a URL representing an OSC address.

Returned value must be free'd.

  void lo_address_set_ttl (lo_address t, int ttl)

Set the Time-to-Live value for a given target address.

This is required for sending multicast UDP messages. A value of 1 (the usual case) keeps the message within the subnet, while 255 means a global, unrestricted scope.

Parameters:
    t An OSC address.
    ttl An integer specifying the scope of a multicast UDP message.

  uint32_t lo_blobsize (lo_blob b)

A function to calculate the amount of OSC message space required by a lo_blob object.

Returns the storage size in bytes, will always be a multiple of four.

  void lo_bundle_add_message (lo_bundle b, const char * path, lo_message m)

Adds an OSC message to an existing bundle.

The message passsed is appended to the list of messages in the bundle to be dispatched to 'path'.

  void lo_bundle_free (lo_bundle b)

Frees the memory taken by a bundle object.

Parameters:
    b The bundle to be freed.

  void lo_bundle_free_messages (lo_bundle b)

Frees the memory taken by a bundle object and messages in the bundle.

Parameters:
    b The bundle, which may contain messages, to be freed.

  size_t lo_bundle_length (lo_bundle b)

Return the length of a bundle in bytes.

Includes the marker and typetage length.

Parameters:
    b The bundle to be sized

  lo_bundle lo_bundle_new (lo_timetag tt)

Create a new bundle object.

OSC Bundles ecapsulate one or more OSC messages and may include a timestamp indicating when the bundle should be dispatched.

Parameters:
    tt The timestamp when the bundle should be handled by the receiver. Pass LO_TT_IMMEDIATE if you want the receiving server to dispatch the bundle as soon as it receives it.

  void* lo_bundle_serialise (lo_bundle b, void * to, size_t * size)

Serialise the bundle object to an area of memory and return a pointer to the serialised form.

Parameters:
    b The bundle to be serialised
    to The address to serialise to, memory will be allocated if to is NULL.
    size If this pointer is non-NULL the size of the memory area will be written here

The returned form is suitable to be sent over a low level OSC transport, having the correct endianess and bit-packed structure.

  int lo_coerce (lo_type type_to, lo_arg * to, lo_type type_from, lo_arg * from)

attempt to convert one OSC type to another.

Numerical types (eg LO_INT32, LO_FLOAT etc.) may be converted to other numerical types and string types (LO_STRING and LO_SYMBOL) may be converted to the other type. This is done automatically if a received message matches the path, but not the exact types, and is coercible (ie. all numerical types in numerical positions).

On failure no translation occurs and false is returned.

Parameters:
    type_to The type of the destination variable.
    to A pointer to the destination variable.
    type_from The type of the source variable.
    from A pointer to the source variable.

  lo_hires lo_hires_val (lo_type type, lo_arg * p)

return the numerical value of the given argument with the maximum native system precision.

  int lo_is_numerical_type (lo_type a)

return true if the type specified has a numerical value, such as LO_INT32, LO_FLOAT etc.

Parameters:
    a The type to be tested.

  int lo_is_string_type (lo_type a)

return true if the type specified has a textual value, such as LO_STRING or LO_SYMBOL.

Parameters:
    a The type to be tested.

  int lo_message_add (lo_message m, const char * types, ...)

Append a number of arguments to a message.

The data will be added in OSC byteorder (bigendian).

Parameters:
    m The message to be extended.
    types The types of the data items in the message, types are defined in lo_types_common.h
    ... The data values to be transmitted. The types of the arguments passed here must agree with the types specified in the type parameter.

Returns:
    Less than 0 on failure, 0 on success.

  void lo_message_add_blob (lo_message m, lo_blob a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_char (lo_message m, char a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_double (lo_message m, double a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_false (lo_message m)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_float (lo_message m, float a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_infinitum (lo_message m)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_int32 (lo_message m, int32_t a)

Append a data item and typechar of the specified type to a message.

The data will be added in OSC byteorder (bigendian).

Parameters:
    m The message to be extended.
    a The data item.

  void lo_message_add_int64 (lo_message m, int64_t a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  int lo_message_add_internal (lo_message m, const char * file, const int line, const char * types, ...)

the real message_add function (don't call directly)

  void lo_message_add_midi (lo_message m, uint8_t a[4])

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_nil (lo_message m)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_string (lo_message m, const char * a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_symbol (lo_message m, const char * a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_timetag (lo_message m, lo_timetag a)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  void lo_message_add_true (lo_message m)

Append a data item and typechar of the specified type to a message. See lo_message_add_int32() for details.

  int lo_message_add_varargs (lo_message m, const char * types, va_list ap)

Append a varargs list to a message.

The data will be added in OSC byteorder (bigendian). IMPORTANT: args list must be terminated with LO_ARGS_END, or this call will fail. This is used to do simple error checking on the sizes of parameters passed.

Parameters:
    m The message to be extended.
    types The types of the data items in the message, types are defined in lo_types_common.h
    ap The va_list created by a C function declared with an ellipsis (...) argument, and pre-initialised with 'va_start(ap)'. The types of the arguments passed here must agree with the types specified in the type parameter.

Returns:
    Less than 0 on failure, 0 on success.

  int lo_message_add_varargs_internal (lo_message m, const char * types, va_list ap, const char * file, const int line)

the real message_add_varargs function (don't call directly)

  lo_message lo_message_deserialise (void * data, size_t size, int * result)

Deserialise a raw OSC message and return a new lo_message object. Opposite of lo_message_serialise().

Parameters:
    data Pointer to the raw OSC message data in network transmission form (network byte order where appropriate).
    size The size of data in bytes
    result If this pointer is non-NULL, the result or error code will be written here.

Returns a new lo_message, or NULL if deserialisation fails. Use lo_message_free() to free the resulting object.

  void lo_message_free (lo_message m)

Free memory allocated by lo_message_new and any subsequent lo_message_add*() calls.

  int lo_message_get_argc (lo_message m)

Return the message argument count.

The result is valid until further data is added with lo_message_add*().

  lo_arg** lo_message_get_argv (lo_message m)

Return the message arguments. Do not free the returned data.

The result is valid until further data is added with lo_message_add*().

  lo_address lo_message_get_source (lo_message m)

Returns the source (lo_address) of an incoming message.

Returns NULL if the message is outgoing. Do not free the returned address.

  char* lo_message_get_types (lo_message m)

Return the message type tag string.

The result is valid until further data is added with lo_message_add*().

  size_t lo_message_length (lo_message m, const char * path)

Return the length of a message in bytes.

Parameters:
    m The message to be sized
    path The path the message will be sent to

  lo_message lo_message_new ()

Create a new lo_message object.

  void* lo_message_serialise (lo_message m, const char * path, void * to, size_t * size)

Serialise the lo_message object to an area of memory and return a pointer to the serialised form. Opposite of lo_message_deserialise().

Parameters:
    m The message to be serialised
    path The path the message will be sent to
    to The address to serialise to, memory will be allocated if to is NULL.
    size If this pointer is non-NULL the size of the memory area will be written here

The returned form is suitable to be sent over a low level OSC transport, having the correct endianess and bit-packed structure.

  int lo_pattern_match (const char * str, const char * p)

Test a string against an OSC pattern glob.

Parameters:
    str The tring to test
    p The pattern to test against

  int lo_send_bundle (lo_address targ, lo_bundle b)

send a lo_bundle object to address targ

Bundles are constructed with the lo_bundle_new() and lo_bundle_add_message() functions.

  int lo_send_bundle_from (lo_address targ, lo_server serv, lo_bundle b)

send a lo_bundle object to address targ from address of serv

Bundles are constructed with the lo_bundle_new() and lo_bundle_add_message() functions.

Parameters:
    targ The address to send the bundle to
    serv The server socket to send the bundle from (can be NULL to use new socket)
    b The bundle itself

  int lo_send_from_internal (lo_address targ, lo_server from, const char * file, const int line, const lo_timetag ts, const char * path, const char * types, ...)

the real lo_send_from function (don't call directly)

  int lo_send_internal (lo_address t, const char * file, const int line, const char * path, const char * types, ...)

the real send function (don't call directly)

  int lo_send_message (lo_address targ, const char * path, lo_message msg)

send a lo_message object to target targ

This is slightly more efficient than lo_send if you want to send a lot of similar messages. The messages are constructed with the lo_message_new() and lo_message_add*() functions.

  int lo_send_message_from (lo_address targ, lo_server serv, const char * path, lo_message msg)

send a lo_message object to target targ from address of serv

This is slightly more efficient than lo_send if you want to send a lot of similar messages. The messages are constructed with the lo_message_new() and lo_message_add*() functions.

Parameters:
    targ The address to send the message to
    serv The server socket to send the message from (can be NULL to use new socket)
    path The path to send the message to
    msg The bundle itself

  int lo_send_timestamped_internal (lo_address t, const char * file, const int line, lo_timetag ts, const char * path, const char * types, ...)

the real send_timestamped function (don't call directly)

  lo_method lo_server_add_method (lo_server s, const char * path, const char * typespec, lo_method_handler h, void * user_data)

Add an OSC method to the specifed server.

Parameters:
    s The server the method is to be added to.
    path The OSC path to register the method to. If NULL is passed the method will match all paths.
    typespec The typespec the method accepts. Incoming messages with similar typespecs (e.g. ones with numerical types in the same position) will be coerced to the typespec given here.
    h The method handler callback function that will be called if a matching message is received
    user_data A value that will be passed to the callback function, h, when its invoked matching from this method.

  void lo_server_del_method (lo_server s, const char * path, const char * typespec)

Delete an OSC method from the specifed server.

Parameters:
    s The server the method is to be removed from.
    path The OSC path of the method to delete. If NULL is passed the method will match the generic handler.
    typespec The typespec the method accepts.

  int lo_server_events_pending (lo_server s)

Return true if there are scheduled events (eg. from bundles) waiting to be dispatched by the server.

  void lo_server_free (lo_server s)

Free up memory used by the lo_server object.

  int lo_server_get_port (lo_server s)

Return the port number that the server has bound to.

Useful when NULL is passed for the port number and you wish to know how to address the server.

  int lo_server_get_protocol (lo_server s)

Return the protocol that the server is using.

Returned value will be one of LO_UDP, LO_TCP or LO_UNIX.

  int lo_server_get_socket_fd (lo_server s)

Return the file descriptor of the server socket.

If the server protocol supports exposing the server's underlying receive mechanism for monitoring with select() or poll(), this function returns the file descriptor needed, otherwise, it returns -1.

WARNING: when using this function beware that not all OSC packets that are received are dispatched immediatly. lo_server_events_pending() and lo_server_next_event_delay() can be used to tell if there are pending events and how long before you should attempt to receive them.

  char* lo_server_get_url (lo_server s)

Return an OSC URL that can be used to contact the server.

The return value should bee free()'d when it is no longer needed.

  lo_server lo_server_new (const char * port, lo_err_handler err_h)

Create a new server instance.

lo_servers block until they receive OSC messages. if you want non-blocking behaviour see the lo_server_thread_* functions.

Parameters:
    port If NULL is passed then an unused UDP port will be chosen by the system, its number may be retreived with lo_server_thread_get_port() so it can be passed to clients. Otherwise a decimal port number, service name or UNIX domain socket path may be passed.
    err_h An error callback function that will be called if there is an error in messge reception or server creation. Pass NULL if you do not want error handling.

  lo_server lo_server_new_multicast (const char * group, const char * port, lo_err_handler err_h)

Create a new server instance, and join a UDP multicast group.

Parameters:
    group The multicast group to join. See documentation on IP multicast for the acceptable address range; e.g., http://tldp.org/HOWTO/Multicast-HOWTO-2.html
    port If using UDP then NULL may be passed to find an unused port. Otherwise a decimal port number or service name or may be passed. If using UNIX domain sockets then a socket path should be passed here.
    err_h An error callback function that will be called if there is an error in messge reception or server creation. Pass NULL if you do not want error handling.

  lo_server lo_server_new_with_proto (const char * port, int proto, lo_err_handler err_h)

Create a new server instance, specifying protocol.

lo_servers block until they receive OSC messages. if you want non-blocking behaviour see the lo_server_thread_* functions.

Parameters:
    port If using UDP then NULL may be passed to find an unused port. Otherwise a decimal port number orservice name or may be passed. If using UNIX domain sockets then a socket path should be passed here.
    proto The protocol to use, should be one of LO_UDP, LO_TCP or LO_UNIX.
    err_h An error callback function that will be called if there is an error in messge reception or server creation. Pass NULL if you do not want error handling.

  double lo_server_next_event_delay (lo_server s)

Return the time in seconds until the next scheduled event.

If the delay is greater than 100 seconds then it will return 100.0.

  int lo_server_recv (lo_server s)

Block, waiting for an OSC message to be received.

The return value is the number of bytes in the received message. The message will be dispatched to a matching method if one is found.

  int lo_server_recv_noblock (lo_server s, int timeout)

Look for an OSC message waiting to be received.

Parameters:
    s The server to wait for connections on.
    timeout A timeout in milliseconds to wait for the incoming packet. a value of 0 will return immediatly.

The return value is the number of bytes in the received message or 0 is there is no message. The message will be dispatched to a matching method if one is found.

  int lo_strsize (const char * s)

A function to calculate the amount of OSC message space required by a C char *.

Returns the storage size in bytes, will always be a multiple of four.

  double lo_timetag_diff (lo_timetag a, lo_timetag b)

Find the time difference between two timetags.

Returns a - b in seconds.

  void lo_timetag_now (lo_timetag * t)

Return a timetag for the current time.

On exit the timetag pointed to by t is filled with the OSC represenation of this instant in time.

  char* lo_url_get_hostname (const char * url)

Return the hostname portion of an OSC URL.

The return value should bee free()'d when it is no longer needed.

  char* lo_url_get_path (const char * url)

Return the path portion of an OSC URL.

The return value should bee free()'d when it is no longer needed.

  char* lo_url_get_port (const char * url)

Return the port portion of an OSC URL.

The return value should bee free()'d when it is no longer needed.

  char* lo_url_get_protocol (const char * url)

Return the protocol portion of an OSC URL, eg. udp, tcp.

This library uses OSC URLs of the form: osc.prot://hostname:port/path if the prot part is missing, UDP is assumed.

The return value should bee free()'d when it is no longer needed.