D-Bus  1.9.2
Data Structures | Typedefs | Functions

Message to be sent or received over a DBusConnection. More...

Data Structures

struct  DBusMessageIter
 DBusMessageIter struct; contains no public fields. More...
 

Typedefs

typedef struct DBusMessage DBusMessage
 Opaque data type representing a message received from or to be sent to another application.
 
typedef struct DBusMessageIter DBusMessageIter
 Opaque type representing a message iterator. More...
 

Functions

dbus_uint32_t dbus_message_get_serial (DBusMessage *message)
 Returns the serial of a message or 0 if none has been specified. More...
 
dbus_bool_t dbus_message_set_reply_serial (DBusMessage *message, dbus_uint32_t reply_serial)
 Sets the reply serial of a message (the serial of the message this is a reply to). More...
 
dbus_uint32_t dbus_message_get_reply_serial (DBusMessage *message)
 Returns the serial that the message is a reply to or 0 if none. More...
 
DBusMessagedbus_message_new (int message_type)
 Constructs a new message of the given message type. More...
 
DBusMessagedbus_message_new_method_call (const char *destination, const char *path, const char *iface, const char *method)
 Constructs a new message to invoke a method on a remote object. More...
 
DBusMessagedbus_message_new_method_return (DBusMessage *method_call)
 Constructs a message that is a reply to a method call. More...
 
DBusMessagedbus_message_new_signal (const char *path, const char *iface, const char *name)
 Constructs a new message representing a signal emission. More...
 
DBusMessagedbus_message_new_error (DBusMessage *reply_to, const char *error_name, const char *error_message)
 Creates a new message that is an error reply to another message. More...
 
DBusMessagedbus_message_new_error_printf (DBusMessage *reply_to, const char *error_name, const char *error_format,...)
 Creates a new message that is an error reply to another message, allowing you to use printf formatting. More...
 
DBusMessagedbus_message_copy (const DBusMessage *message)
 Creates a new message that is an exact replica of the message specified, except that its refcount is set to 1, its message serial is reset to 0, and if the original message was "locked" (in the outgoing message queue and thus not modifiable) the new message will not be locked. More...
 
DBusMessagedbus_message_ref (DBusMessage *message)
 Increments the reference count of a DBusMessage. More...
 
void dbus_message_unref (DBusMessage *message)
 Decrements the reference count of a DBusMessage, freeing the message if the count reaches 0. More...
 
int dbus_message_get_type (DBusMessage *message)
 Gets the type of a message. More...
 
dbus_bool_t dbus_message_append_args (DBusMessage *message, int first_arg_type,...)
 Appends fields to a message given a variable argument list. More...
 
dbus_bool_t dbus_message_append_args_valist (DBusMessage *message, int first_arg_type, va_list var_args)
 Like dbus_message_append_args() but takes a va_list for use by language bindings. More...
 
dbus_bool_t dbus_message_get_args (DBusMessage *message, DBusError *error, int first_arg_type,...)
 Gets arguments from a message given a variable argument list. More...
 
dbus_bool_t dbus_message_get_args_valist (DBusMessage *message, DBusError *error, int first_arg_type, va_list var_args)
 Like dbus_message_get_args but takes a va_list for use by language bindings. More...
 
dbus_bool_t dbus_message_iter_init (DBusMessage *message, DBusMessageIter *iter)
 Initializes a DBusMessageIter for reading the arguments of the message passed in. More...
 
dbus_bool_t dbus_message_iter_has_next (DBusMessageIter *iter)
 Checks if an iterator has any more fields. More...
 
dbus_bool_t dbus_message_iter_next (DBusMessageIter *iter)
 Moves the iterator to the next field, if any. More...
 
int dbus_message_iter_get_arg_type (DBusMessageIter *iter)
 Returns the argument type of the argument that the message iterator points to. More...
 
int dbus_message_iter_get_element_type (DBusMessageIter *iter)
 Returns the element type of the array that the message iterator points to. More...
 
void dbus_message_iter_recurse (DBusMessageIter *iter, DBusMessageIter *sub)
 Recurses into a container value when reading values from a message, initializing a sub-iterator to use for traversing the child values of the container. More...
 
char * dbus_message_iter_get_signature (DBusMessageIter *iter)
 Returns the current signature of a message iterator. More...
 
void dbus_message_iter_get_basic (DBusMessageIter *iter, void *value)
 Reads a basic-typed value from the message iterator. More...
 
int dbus_message_iter_get_array_len (DBusMessageIter *iter)
 Returns the number of bytes in the array as marshaled in the wire protocol. More...
 
void dbus_message_iter_get_fixed_array (DBusMessageIter *iter, void *value, int *n_elements)
 Reads a block of fixed-length values from the message iterator. More...
 
void dbus_message_iter_init_append (DBusMessage *message, DBusMessageIter *iter)
 Initializes a DBusMessageIter for appending arguments to the end of a message. More...
 
dbus_bool_t dbus_message_iter_append_basic (DBusMessageIter *iter, int type, const void *value)
 Appends a basic-typed value to the message. More...
 
dbus_bool_t dbus_message_iter_append_fixed_array (DBusMessageIter *iter, int element_type, const void *value, int n_elements)
 Appends a block of fixed-length values to an array. More...
 
dbus_bool_t dbus_message_iter_open_container (DBusMessageIter *iter, int type, const char *contained_signature, DBusMessageIter *sub)
 Appends a container-typed value to the message; you are required to append the contents of the container using the returned sub-iterator, and then call dbus_message_iter_close_container(). More...
 
dbus_bool_t dbus_message_iter_close_container (DBusMessageIter *iter, DBusMessageIter *sub)
 Closes a container-typed value appended to the message; may write out more information to the message known only after the entire container is written, and may free resources created by dbus_message_iter_open_container(). More...
 
void dbus_message_iter_abandon_container (DBusMessageIter *iter, DBusMessageIter *sub)
 Abandons creation of a contained-typed value and frees resources created by dbus_message_iter_open_container(). More...
 
void dbus_message_set_no_reply (DBusMessage *message, dbus_bool_t no_reply)
 Sets a flag indicating that the message does not want a reply; if this flag is set, the other end of the connection may (but is not required to) optimize by not sending method return or error replies. More...
 
dbus_bool_t dbus_message_get_no_reply (DBusMessage *message)
 Returns TRUE if the message does not expect a reply. More...
 
void dbus_message_set_auto_start (DBusMessage *message, dbus_bool_t auto_start)
 Sets a flag indicating that an owner for the destination name will be automatically started before the message is delivered. More...
 
dbus_bool_t dbus_message_get_auto_start (DBusMessage *message)
 Returns TRUE if the message will cause an owner for destination name to be auto-started. More...
 
dbus_bool_t dbus_message_set_path (DBusMessage *message, const char *object_path)
 Sets the object path this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or the one a signal is being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL). More...
 
const char * dbus_message_get_path (DBusMessage *message)
 Gets the object path this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL). More...
 
dbus_bool_t dbus_message_has_path (DBusMessage *message, const char *path)
 Checks if the message has a particular object path. More...
 
dbus_bool_t dbus_message_get_path_decomposed (DBusMessage *message, char ***path)
 Gets the object path this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL) in a decomposed format (one array element per path component). More...
 
dbus_bool_t dbus_message_set_interface (DBusMessage *message, const char *iface)
 Sets the interface this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or the interface a signal is being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL). More...
 
const char * dbus_message_get_interface (DBusMessage *message)
 Gets the interface this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL). More...
 
dbus_bool_t dbus_message_has_interface (DBusMessage *message, const char *iface)
 Checks if the message has an interface. More...
 
dbus_bool_t dbus_message_set_member (DBusMessage *message, const char *member)
 Sets the interface member being invoked (DBUS_MESSAGE_TYPE_METHOD_CALL) or emitted (DBUS_MESSAGE_TYPE_SIGNAL). More...
 
const char * dbus_message_get_member (DBusMessage *message)
 Gets the interface member being invoked (DBUS_MESSAGE_TYPE_METHOD_CALL) or emitted (DBUS_MESSAGE_TYPE_SIGNAL). More...
 
dbus_bool_t dbus_message_has_member (DBusMessage *message, const char *member)
 Checks if the message has an interface member. More...
 
dbus_bool_t dbus_message_set_error_name (DBusMessage *message, const char *error_name)
 Sets the name of the error (DBUS_MESSAGE_TYPE_ERROR). More...
 
const char * dbus_message_get_error_name (DBusMessage *message)
 Gets the error name (DBUS_MESSAGE_TYPE_ERROR only) or NULL if none. More...
 
dbus_bool_t dbus_message_set_destination (DBusMessage *message, const char *destination)
 Sets the message's destination. More...
 
const char * dbus_message_get_destination (DBusMessage *message)
 Gets the destination of a message or NULL if there is none set. More...
 
dbus_bool_t dbus_message_set_sender (DBusMessage *message, const char *sender)
 Sets the message sender. More...
 
const char * dbus_message_get_sender (DBusMessage *message)
 Gets the unique name of the connection which originated this message, or NULL if unknown or inapplicable. More...
 
const char * dbus_message_get_signature (DBusMessage *message)
 Gets the type signature of the message, i.e. More...
 
dbus_bool_t dbus_message_is_method_call (DBusMessage *message, const char *iface, const char *method)
 Checks whether the message is a method call with the given interface and member fields. More...
 
dbus_bool_t dbus_message_is_signal (DBusMessage *message, const char *iface, const char *signal_name)
 Checks whether the message is a signal with the given interface and member fields. More...
 
dbus_bool_t dbus_message_is_error (DBusMessage *message, const char *error_name)
 Checks whether the message is an error reply with the given error name. More...
 
dbus_bool_t dbus_message_has_destination (DBusMessage *message, const char *name)
 Checks whether the message was sent to the given name. More...
 
dbus_bool_t dbus_message_has_sender (DBusMessage *message, const char *name)
 Checks whether the message has the given unique name as its sender. More...
 
dbus_bool_t dbus_message_has_signature (DBusMessage *message, const char *signature)
 Checks whether the message has the given signature; see dbus_message_get_signature() for more details on what the signature looks like. More...
 
dbus_bool_t dbus_set_error_from_message (DBusError *error, DBusMessage *message)
 Sets a DBusError based on the contents of the given message. More...
 
dbus_bool_t dbus_message_contains_unix_fds (DBusMessage *message)
 Checks whether a message contains unix fds. More...
 
DBUS_EXPORT void dbus_message_set_serial (DBusMessage *message, dbus_uint32_t serial)
 Sets the serial number of a message. More...
 
DBUS_EXPORT void dbus_message_lock (DBusMessage *message)
 Locks a message. More...
 
DBUS_EXPORT dbus_bool_t dbus_message_allocate_data_slot (dbus_int32_t *slot_p)
 Allocates an integer ID to be used for storing application-specific data on any DBusMessage. More...
 
DBUS_EXPORT void dbus_message_free_data_slot (dbus_int32_t *slot_p)
 Deallocates a global ID for message data slots. More...
 
DBUS_EXPORT dbus_bool_t dbus_message_set_data (DBusMessage *message, dbus_int32_t slot, void *data, DBusFreeFunction free_data_func)
 Stores a pointer on a DBusMessage, along with an optional function to be used for freeing the data when the data is set again, or when the message is finalized. More...
 
DBUS_EXPORT void * dbus_message_get_data (DBusMessage *message, dbus_int32_t slot)
 Retrieves data previously set with dbus_message_set_data(). More...
 
DBUS_EXPORT int dbus_message_type_from_string (const char *type_str)
 Utility function to convert a machine-readable (not translated) string into a D-Bus message type. More...
 
DBUS_EXPORT const char * dbus_message_type_to_string (int type)
 Utility function to convert a D-Bus message type into a machine-readable string (not translated). More...
 
DBUS_EXPORT dbus_bool_t dbus_message_marshal (DBusMessage *msg, char **marshalled_data_p, int *len_p)
 Turn a DBusMessage into the marshalled form as described in the D-Bus specification. More...
 
DBUS_EXPORT DBusMessagedbus_message_demarshal (const char *str, int len, DBusError *error)
 Demarshal a D-Bus message from the format described in the D-Bus specification. More...
 
DBUS_EXPORT int dbus_message_demarshal_bytes_needed (const char *str, int len)
 Returns the number of bytes required to be in the buffer to demarshal a D-Bus message. More...
 
DBUS_EXPORT void dbus_message_set_allow_interactive_authorization (DBusMessage *message, dbus_bool_t allow)
 Sets a flag indicating that the caller of the method is prepared to wait for interactive authorization to take place (for instance via Polkit) before the actual method is processed. More...
 
DBUS_EXPORT dbus_bool_t dbus_message_get_allow_interactive_authorization (DBusMessage *message)
 Returns whether the flag controlled by dbus_message_set_allow_interactive_authorization() has been set. More...
 

Detailed Description

Message to be sent or received over a DBusConnection.

A DBusMessage is the most basic unit of communication over a DBusConnection. A DBusConnection represents a stream of messages received from a remote application, and a stream of messages sent to a remote application.

A message has a message type, returned from dbus_message_get_type(). This indicates whether the message is a method call, a reply to a method call, a signal, or an error reply.

A message has header fields such as the sender, destination, method or signal name, and so forth. DBusMessage has accessor functions for these, such as dbus_message_get_member().

Convenience functions dbus_message_is_method_call(), dbus_message_is_signal(), and dbus_message_is_error() check several header fields at once and are slightly more efficient than checking the header fields with individual accessor functions.

Finally, a message has arguments. The number and types of arguments are in the message's signature header field (accessed with dbus_message_get_signature()). Simple argument values are usually retrieved with dbus_message_get_args() but more complex values such as structs may require the use of DBusMessageIter.

The D-Bus specification goes into some more detail about header fields and message types.

Typedef Documentation

Opaque type representing a message iterator.

Can be copied by value, and contains no allocated memory so never needs to be freed and can be allocated on the stack.

Definition at line 46 of file dbus-message.h.

Function Documentation

DBUS_EXPORT dbus_bool_t dbus_message_allocate_data_slot ( dbus_int32_t *  slot_p)

Allocates an integer ID to be used for storing application-specific data on any DBusMessage.

The allocated ID may then be used with dbus_message_set_data() and dbus_message_get_data(). The passed-in slot must be initialized to -1, and is filled in with the slot ID. If the passed-in slot is not -1, it's assumed to be already allocated, and its refcount is incremented.

The allocated slot is global, i.e. all DBusMessage objects will have a slot with the given integer ID reserved.

Parameters
slot_paddress of a global variable storing the slot
Returns
FALSE on failure (no memory)

Definition at line 4560 of file dbus-message.c.

References _dbus_data_slot_allocator_alloc().

DBUS_EXPORT dbus_bool_t dbus_message_append_args ( DBusMessage message,
int  first_arg_type,
  ... 
)

Appends fields to a message given a variable argument list.

The variable argument list should contain the type of each argument followed by the value to append. Appendable types are basic types, and arrays of fixed-length basic types (except arrays of Unix file descriptors). To append variable-length basic types, or any more complex value, you have to use an iterator rather than this function.

To append a basic type, specify its type code followed by the address of the value. For example:

1 dbus_int32_t v_INT32 = 42;
2 const char *v_STRING = "Hello World";
3 dbus_message_append_args (message,
4  DBUS_TYPE_INT32, &v_INT32,
5  DBUS_TYPE_STRING, &v_STRING,
6  DBUS_TYPE_INVALID);

To append an array of fixed-length basic types (except Unix file descriptors), pass in the DBUS_TYPE_ARRAY typecode, the element typecode, the address of the array pointer, and a 32-bit integer giving the number of elements in the array. So for example:

1 const dbus_int32_t array[] = { 1, 2, 3 }; const dbus_int32_t
2 *v_ARRAY = array; dbus_message_append_args (message,
3 DBUS_TYPE_ARRAY, DBUS_TYPE_INT32, &v_ARRAY, 3, DBUS_TYPE_INVALID);

This function does not support arrays of Unix file descriptors. If you need those you need to manually recurse into the array.

For Unix file descriptors this function will internally duplicate the descriptor you passed in. Hence you may close the descriptor immediately after this call.

Warning
in C, given "int array[]", "&array == array" (the comp.lang.c FAQ says otherwise, but gcc and the FAQ don't agree). So if you're using an array instead of a pointer you have to create a pointer variable, assign the array to it, then take the address of the pointer variable. For strings it works to write const char *array = "Hello" and then use &array though.

The last argument to this function must be DBUS_TYPE_INVALID, marking the end of the argument list. If you don't do this then libdbus won't know to stop and will read invalid memory.

String/signature/path arrays should be passed in as "const char*** address_of_array" and "int n_elements"

Todo:
support DBUS_TYPE_STRUCT and DBUS_TYPE_VARIANT and complex arrays
Todo:
If this fails due to lack of memory, the message is hosed and you have to start over building the whole message.
Parameters
messagethe message
first_arg_typetype of the first argument
...value of first argument, list of additional type-value pairs
Returns
TRUE on success

Definition at line 1792 of file dbus-message.c.

References dbus_message_append_args_valist(), FALSE, and NULL.

Referenced by dbus_bus_add_match(), dbus_bus_get_unix_user(), dbus_bus_name_has_owner(), dbus_bus_release_name(), dbus_bus_remove_match(), dbus_bus_request_name(), and dbus_bus_start_service_by_name().

DBUS_EXPORT dbus_bool_t dbus_message_append_args_valist ( DBusMessage message,
int  first_arg_type,
va_list  var_args 
)

Like dbus_message_append_args() but takes a va_list for use by language bindings.

Todo:
for now, if this function fails due to OOM it will leave the message half-written and you have to discard the message and start over.
See also
dbus_message_append_args.
Parameters
messagethe message
first_arg_typetype of first argument
var_argsvalue of first argument, then list of type/value pairs
Returns
TRUE on success

Definition at line 1824 of file dbus-message.c.

References _dbus_type_to_string(), _dbus_warn(), dbus_message_iter_abandon_container(), dbus_message_iter_append_basic(), dbus_message_iter_append_fixed_array(), dbus_message_iter_close_container(), dbus_message_iter_init_append(), dbus_message_iter_open_container(), DBUS_TYPE_ARRAY, DBUS_TYPE_INVALID, dbus_type_is_basic(), dbus_type_is_fixed(), DBUS_TYPE_UNIX_FD, FALSE, NULL, and TRUE.

Referenced by dbus_message_append_args().

DBUS_EXPORT dbus_bool_t dbus_message_contains_unix_fds ( DBusMessage message)

Checks whether a message contains unix fds.

Parameters
messagethe message
Returns
TRUE if the message contains unix fds

Definition at line 3825 of file dbus-message.c.

References _dbus_assert, and FALSE.

DBUS_EXPORT DBusMessage * dbus_message_copy ( const DBusMessage message)

Creates a new message that is an exact replica of the message specified, except that its refcount is set to 1, its message serial is reset to 0, and if the original message was "locked" (in the outgoing message queue and thus not modifiable) the new message will not be locked.

Todo:
This function can't be used in programs that try to recover from OOM errors.
Parameters
messagethe message
Returns
the new message.or NULL if not enough memory or Unix file descriptors (in case the message to copy includes Unix file descriptors) can be allocated.

Definition at line 1587 of file dbus-message.c.

References _dbus_atomic_inc(), _dbus_dup(), _dbus_header_copy(), _dbus_header_free(), _dbus_string_copy(), _dbus_string_free(), _dbus_string_get_length(), _dbus_string_init_preallocated(), body, dbus_free(), dbus_new, dbus_new0, FALSE, generation, header, locked, NULL, and refcount.

DBUS_EXPORT DBusMessage* dbus_message_demarshal ( const char *  str,
int  len,
DBusError error 
)

Demarshal a D-Bus message from the format described in the D-Bus specification.

Generally, this function is only useful for encapsulating D-Bus messages in a different protocol.

Parameters
strthe marshalled DBusMessage
lenthe length of str
errorthe location to save errors to
Returns
NULL if there was an error

Definition at line 4783 of file dbus-message.c.

References _dbus_message_loader_get_buffer(), _dbus_message_loader_get_is_corrupted(), _dbus_message_loader_new(), _dbus_message_loader_pop_message(), _dbus_message_loader_queue_messages(), _dbus_message_loader_return_buffer(), _dbus_message_loader_unref(), _dbus_string_append_len(), DBusMessageLoader::corruption_reason, DBUS_ERROR_INVALID_ARGS, dbus_set_error(), and NULL.

DBUS_EXPORT int dbus_message_demarshal_bytes_needed ( const char *  buf,
int  len 
)

Returns the number of bytes required to be in the buffer to demarshal a D-Bus message.

Generally, this function is only useful for encapsulating D-Bus messages in a different protocol.

Parameters
bufdata to be marshalled
lenthe length of buf
Returns
-1 if there was no valid data to be demarshalled, 0 if there wasn't enough data to determine how much should be demarshalled. Otherwise returns the number of bytes to be demarshalled

Definition at line 4841 of file dbus-message.c.

References _dbus_assert, _dbus_header_have_message_untrusted(), _dbus_string_free(), _dbus_string_init_const_len(), DBUS_MAXIMUM_MESSAGE_LENGTH, DBUS_MINIMUM_HEADER_SIZE, and DBUS_VALID.

DBUS_EXPORT void dbus_message_free_data_slot ( dbus_int32_t *  slot_p)

Deallocates a global ID for message data slots.

dbus_message_get_data() and dbus_message_set_data() may no longer be used with this slot. Existing data stored on existing DBusMessage objects will be freed when the message is finalized, but may not be retrieved (and may only be replaced if someone else reallocates the slot). When the refcount on the passed-in slot reaches 0, it is set to -1.

Parameters
slot_paddress storing the slot to deallocate

Definition at line 4578 of file dbus-message.c.

References _dbus_data_slot_allocator_free().

DBUS_EXPORT dbus_bool_t dbus_message_get_allow_interactive_authorization ( DBusMessage message)

Returns whether the flag controlled by dbus_message_set_allow_interactive_authorization() has been set.

Parameters
messagethe message

Definition at line 4919 of file dbus-message.c.

References _dbus_header_get_flag(), DBUS_HEADER_FLAG_ALLOW_INTERACTIVE_AUTHORIZATION, FALSE, header, and NULL.

DBUS_EXPORT dbus_bool_t dbus_message_get_args ( DBusMessage message,
DBusError error,
int  first_arg_type,
  ... 
)

Gets arguments from a message given a variable argument list.

The supported types include those supported by dbus_message_append_args(); that is, basic types and arrays of fixed-length basic types. The arguments are the same as they would be for dbus_message_iter_get_basic() or dbus_message_iter_get_fixed_array().

In addition to those types, arrays of string, object path, and signature are supported; but these are returned as allocated memory and must be freed with dbus_free_string_array(), while the other types are returned as const references. To get a string array pass in "char ***array_location" and "int *n_elements".

Similar to dbus_message_get_fixed_array() this function does not support arrays of type DBUS_TYPE_UNIX_FD. If you need to parse messages with arrays of Unix file descriptors you need to recurse into the array manually.

Unix file descriptors that are read with this function will have the FD_CLOEXEC flag set. If you need them without this flag set, make sure to unset it with fcntl().

The variable argument list should contain the type of the argument followed by a pointer to where the value should be stored. The list is terminated with DBUS_TYPE_INVALID.

Except for string arrays, the returned values are constant; do not free them. They point into the DBusMessage.

If the requested arguments are not present, or do not have the requested types, then an error will be set.

If more arguments than requested are present, the requested arguments are returned and the extra arguments are ignored.

Todo:
support DBUS_TYPE_STRUCT and DBUS_TYPE_VARIANT and complex arrays
Parameters
messagethe message
errorerror to be filled in on failure
first_arg_typethe first argument type
...location for first argument value, then list of type-location pairs
Returns
FALSE if the error was set

Definition at line 1980 of file dbus-message.c.

References dbus_message_get_args_valist(), FALSE, and NULL.

Referenced by dbus_bus_get_id(), dbus_bus_get_unix_user(), dbus_bus_name_has_owner(), dbus_bus_register(), dbus_bus_release_name(), dbus_bus_request_name(), dbus_bus_start_service_by_name(), and dbus_set_error_from_message().

DBUS_EXPORT dbus_bool_t dbus_message_get_args_valist ( DBusMessage message,
DBusError error,
int  first_arg_type,
va_list  var_args 
)

Like dbus_message_get_args but takes a va_list for use by language bindings.

See also
dbus_message_get_args
Parameters
messagethe message
errorerror to be filled in
first_arg_typetype of the first argument
var_argsreturn location for first argument, followed by list of type/location pairs
Returns
FALSE if error was set

Definition at line 2009 of file dbus-message.c.

References _dbus_message_iter_get_args_valist(), dbus_message_iter_init(), FALSE, and NULL.

Referenced by dbus_message_get_args().

DBUS_EXPORT dbus_bool_t dbus_message_get_auto_start ( DBusMessage message)

Returns TRUE if the message will cause an owner for destination name to be auto-started.

Parameters
messagethe message
Returns
TRUE if the message will use auto-start

Definition at line 3045 of file dbus-message.c.

References _dbus_header_get_flag(), DBUS_HEADER_FLAG_NO_AUTO_START, FALSE, header, and NULL.

DBUS_EXPORT void* dbus_message_get_data ( DBusMessage message,
dbus_int32_t  slot 
)

Retrieves data previously set with dbus_message_set_data().

The slot must still be allocated (must not have been freed).

Parameters
messagethe message
slotthe slot to get data from
Returns
the data, or NULL if not found

Definition at line 4635 of file dbus-message.c.

References _dbus_data_slot_list_get(), NULL, and slot_list.

DBUS_EXPORT const char * dbus_message_get_destination ( DBusMessage message)

Gets the destination of a message or NULL if there is none set.

The returned string becomes invalid if the message is modified, since it points into the wire-marshaled message data.

Parameters
messagethe message
Returns
the message destination (should not be freed) or NULL

Definition at line 3450 of file dbus-message.c.

References _dbus_header_get_field_basic(), DBUS_HEADER_FIELD_DESTINATION, DBUS_TYPE_STRING, header, and NULL.

Referenced by dbus_message_has_destination().

DBUS_EXPORT const char * dbus_message_get_error_name ( DBusMessage message)

Gets the error name (DBUS_MESSAGE_TYPE_ERROR only) or NULL if none.

The returned string becomes invalid if the message is modified, since it points into the wire-marshaled message data.

Parameters
messagethe message
Returns
the error name (should not be freed) or NULL

Definition at line 3397 of file dbus-message.c.

References _dbus_header_get_field_basic(), DBUS_HEADER_FIELD_ERROR_NAME, DBUS_TYPE_STRING, header, and NULL.

Referenced by dbus_message_is_error(), and dbus_set_error_from_message().

DBUS_EXPORT const char * dbus_message_get_interface ( DBusMessage message)

Gets the interface this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL).

The interface name is fully-qualified (namespaced). Returns NULL if none.

The returned string becomes invalid if the message is modified, since it points into the wire-marshaled message data.

Parameters
messagethe message
Returns
the message interface (should not be freed) or NULL

Definition at line 3227 of file dbus-message.c.

References _dbus_header_get_field_basic(), DBUS_HEADER_FIELD_INTERFACE, DBUS_TYPE_STRING, header, and NULL.

Referenced by _dbus_connection_message_sent_unlocked(), _dbus_connection_queue_received_message_link(), dbus_connection_dispatch(), dbus_connection_send_preallocated(), and dbus_message_has_interface().

DBUS_EXPORT const char * dbus_message_get_member ( DBusMessage message)

Gets the interface member being invoked (DBUS_MESSAGE_TYPE_METHOD_CALL) or emitted (DBUS_MESSAGE_TYPE_SIGNAL).

Returns NULL if none.

The returned string becomes invalid if the message is modified, since it points into the wire-marshaled message data.

Parameters
messagethe message
Returns
the member name (should not be freed) or NULL

Definition at line 3313 of file dbus-message.c.

References _dbus_header_get_field_basic(), DBUS_HEADER_FIELD_MEMBER, DBUS_TYPE_STRING, header, and NULL.

Referenced by _dbus_connection_message_sent_unlocked(), _dbus_connection_queue_received_message_link(), dbus_connection_dispatch(), dbus_connection_send_preallocated(), and dbus_message_has_member().

DBUS_EXPORT dbus_bool_t dbus_message_get_no_reply ( DBusMessage message)

Returns TRUE if the message does not expect a reply.

Parameters
messagethe message
Returns
TRUE if the message sender isn't waiting for a reply

Definition at line 3003 of file dbus-message.c.

References _dbus_header_get_flag(), DBUS_HEADER_FLAG_NO_REPLY_EXPECTED, FALSE, header, and NULL.

DBUS_EXPORT const char * dbus_message_get_path ( DBusMessage message)

Gets the object path this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL).

Returns NULL if none.

See also dbus_message_get_path_decomposed().

The returned string becomes invalid if the message is modified, since it points into the wire-marshaled message data.

Parameters
messagethe message
Returns
the path (should not be freed) or NULL

Definition at line 3096 of file dbus-message.c.

References _dbus_header_get_field_basic(), DBUS_HEADER_FIELD_PATH, DBUS_TYPE_OBJECT_PATH, header, and NULL.

Referenced by _dbus_connection_message_sent_unlocked(), _dbus_connection_queue_received_message_link(), dbus_message_get_path_decomposed(), and dbus_message_has_path().

DBUS_EXPORT dbus_bool_t dbus_message_get_path_decomposed ( DBusMessage message,
char ***  path 
)

Gets the object path this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL) in a decomposed format (one array element per path component).

Free the returned array with dbus_free_string_array().

An empty but non-NULL path array means the path "/". So the path "/foo/bar" becomes { "foo", "bar", NULL } and the path "/" becomes { NULL }.

See also dbus_message_get_path().

Todo:
this could be optimized by using the len from the message instead of calling strlen() again
Parameters
messagethe message
pathplace to store allocated array of path components; NULL set here if no path field exists
Returns
FALSE if no memory to allocate the array

Definition at line 3164 of file dbus-message.c.

References _dbus_decompose_path(), dbus_message_get_path(), FALSE, NULL, and TRUE.

Referenced by _dbus_object_tree_dispatch_and_unlock().

DBUS_EXPORT dbus_uint32_t dbus_message_get_reply_serial ( DBusMessage message)

Returns the serial that the message is a reply to or 0 if none.

Parameters
messagethe message
Returns
the reply serial

Definition at line 1163 of file dbus-message.c.

References _dbus_header_get_field_basic(), DBUS_HEADER_FIELD_REPLY_SERIAL, DBUS_TYPE_UINT32, header, and NULL.

Referenced by _dbus_connection_queue_received_message_link(), _dbus_pending_call_set_reply_unlocked(), and dbus_connection_dispatch().

DBUS_EXPORT const char * dbus_message_get_sender ( DBusMessage message)

Gets the unique name of the connection which originated this message, or NULL if unknown or inapplicable.

The sender is filled in by the message bus.

Note, the returned sender is always the unique bus name. Connections may own multiple other bus names, but those are not found in the sender field.

The returned string becomes invalid if the message is modified, since it points into the wire-marshaled message data.

Parameters
messagethe message
Returns
the unique name of the sender or NULL

Definition at line 3510 of file dbus-message.c.

References _dbus_header_get_field_basic(), DBUS_HEADER_FIELD_SENDER, DBUS_TYPE_STRING, header, and NULL.

Referenced by dbus_message_has_sender(), dbus_message_new_error(), and dbus_message_new_method_return().

DBUS_EXPORT dbus_uint32_t dbus_message_get_serial ( DBusMessage message)

Returns the serial of a message or 0 if none has been specified.

The message's serial number is provided by the application sending the message and is used to identify replies to this message.

All messages received on a connection will have a serial provided by the remote application.

For messages you're sending, dbus_connection_send() will assign a serial and return it to you.

Parameters
messagethe message
Returns
the serial

Definition at line 1127 of file dbus-message.c.

References _dbus_header_get_serial(), header, and NULL.

Referenced by dbus_connection_send_with_reply(), dbus_message_new_error(), and dbus_message_new_method_return().

DBUS_EXPORT const char * dbus_message_get_signature ( DBusMessage message)

Gets the type signature of the message, i.e.

the arguments in the message payload. The signature includes only "in" arguments for DBUS_MESSAGE_TYPE_METHOD_CALL and only "out" arguments for DBUS_MESSAGE_TYPE_METHOD_RETURN, so is slightly different from what you might expect (that is, it does not include the signature of the entire C++-style method).

The signature is a string made up of type codes such as DBUS_TYPE_INT32. The string is terminated with nul (nul is also the value of DBUS_TYPE_INVALID).

The returned string becomes invalid if the message is modified, since it points into the wire-marshaled message data.

Parameters
messagethe message
Returns
the type signature

Definition at line 3543 of file dbus-message.c.

References _dbus_string_get_const_data_len(), header, and NULL.

Referenced by _dbus_connection_message_sent_unlocked(), _dbus_connection_queue_received_message_link(), dbus_connection_dispatch(), dbus_message_has_signature(), and dbus_message_lock().

DBUS_EXPORT int dbus_message_get_type ( DBusMessage message)

Gets the type of a message.

Types include DBUS_MESSAGE_TYPE_METHOD_CALL, DBUS_MESSAGE_TYPE_METHOD_RETURN, DBUS_MESSAGE_TYPE_ERROR, DBUS_MESSAGE_TYPE_SIGNAL, but other types are allowed and all code must silently ignore messages of unknown type. DBUS_MESSAGE_TYPE_INVALID will never be returned.

Parameters
messagethe message
Returns
the type of the message

Definition at line 1722 of file dbus-message.c.

References _dbus_header_get_message_type(), DBUS_MESSAGE_TYPE_INVALID, header, and NULL.

Referenced by _dbus_connection_message_sent_unlocked(), _dbus_connection_queue_received_message_link(), _dbus_pending_call_set_reply_unlocked(), dbus_connection_dispatch(), dbus_connection_send_preallocated(), dbus_message_is_error(), and dbus_set_error_from_message().

DBUS_EXPORT dbus_bool_t dbus_message_has_destination ( DBusMessage message,
const char *  name 
)

Checks whether the message was sent to the given name.

If the message has no destination specified or has a different destination, returns FALSE.

Parameters
messagethe message
namethe name to check (must not be NULL)
Returns
TRUE if the message has the given destination name

Definition at line 3690 of file dbus-message.c.

References dbus_message_get_destination(), FALSE, NULL, and TRUE.

DBUS_EXPORT dbus_bool_t dbus_message_has_interface ( DBusMessage message,
const char *  iface 
)

Checks if the message has an interface.

Parameters
messagethe message
ifacethe interface name
Returns
TRUE if the interface field in the header matches

Definition at line 3249 of file dbus-message.c.

References dbus_message_get_interface(), FALSE, NULL, and TRUE.

DBUS_EXPORT dbus_bool_t dbus_message_has_member ( DBusMessage message,
const char *  member 
)

Checks if the message has an interface member.

Parameters
messagethe message
memberthe member name
Returns
TRUE if there is a member field in the header

Definition at line 3335 of file dbus-message.c.

References dbus_message_get_member(), FALSE, NULL, and TRUE.

DBUS_EXPORT dbus_bool_t dbus_message_has_path ( DBusMessage message,
const char *  path 
)

Checks if the message has a particular object path.

The object path is the destination object for a method call or the emitting object for a signal.

Parameters
messagethe message
paththe path name
Returns
TRUE if there is a path field in the header

Definition at line 3120 of file dbus-message.c.

References dbus_message_get_path(), FALSE, NULL, and TRUE.

DBUS_EXPORT dbus_bool_t dbus_message_has_sender ( DBusMessage message,
const char *  name 
)

Checks whether the message has the given unique name as its sender.

If the message has no sender specified or has a different sender, returns FALSE. Note that a peer application will always have the unique name of the connection as the sender. So you can't use this function to see whether a sender owned a well-known name.

Messages from the bus itself will have DBUS_SERVICE_DBUS as the sender.

Parameters
messagethe message
namethe name to check (must not be NULL)
Returns
TRUE if the message has the given sender

Definition at line 3725 of file dbus-message.c.

References dbus_message_get_sender(), FALSE, NULL, and TRUE.

DBUS_EXPORT dbus_bool_t dbus_message_has_signature ( DBusMessage message,
const char *  signature 
)

Checks whether the message has the given signature; see dbus_message_get_signature() for more details on what the signature looks like.

Parameters
messagethe message
signaturetypecode array
Returns
TRUE if message has the given signature

Definition at line 3754 of file dbus-message.c.

References dbus_message_get_signature(), FALSE, NULL, and TRUE.

DBUS_EXPORT dbus_bool_t dbus_message_is_error ( DBusMessage message,
const char *  error_name 
)

Checks whether the message is an error reply with the given error name.

If the message is not DBUS_MESSAGE_TYPE_ERROR, or has a different name, returns FALSE.

Parameters
messagethe message
error_namethe name to check (must not be NULL)
Returns
TRUE if the message is the specified error

Definition at line 3657 of file dbus-message.c.

References dbus_message_get_error_name(), dbus_message_get_type(), DBUS_MESSAGE_TYPE_ERROR, FALSE, NULL, and TRUE.

DBUS_EXPORT dbus_bool_t dbus_message_is_method_call ( DBusMessage message,
const char *  iface,
const char *  method 
)

Checks whether the message is a method call with the given interface and member fields.

If the message is not DBUS_MESSAGE_TYPE_METHOD_CALL, or has a different interface or member field, returns FALSE. If the interface field is missing, then it will be assumed equal to the provided interface. The D-Bus protocol allows method callers to leave out the interface name.

Parameters
messagethe message
ifacethe name to check (must not be NULL)
methodthe name to check (must not be NULL)
Returns
TRUE if the message is the specified method call

Definition at line 3602 of file dbus-message.c.

References DBUS_MESSAGE_TYPE_METHOD_CALL, FALSE, and NULL.

DBUS_EXPORT dbus_bool_t dbus_message_is_signal ( DBusMessage message,
const char *  iface,
const char *  signal_name 
)

Checks whether the message is a signal with the given interface and member fields.

If the message is not DBUS_MESSAGE_TYPE_SIGNAL, or has a different interface or member field, returns FALSE.

Parameters
messagethe message
ifacethe name to check (must not be NULL)
signal_namethe name to check (must not be NULL)
Returns
TRUE if the message is the specified signal

Definition at line 3630 of file dbus-message.c.

References DBUS_MESSAGE_TYPE_SIGNAL, FALSE, and NULL.

DBUS_EXPORT void dbus_message_iter_abandon_container ( DBusMessageIter iter,
DBusMessageIter sub 
)

Abandons creation of a contained-typed value and frees resources created by dbus_message_iter_open_container().

Once this returns, the message is hosed and you have to start over building the whole message.

This should only be used to abandon creation of a message when you have open containers.

Parameters
iterthe append iterator
subsub-iterator to close

Definition at line 2951 of file dbus-message.c.

References DBusMessageRealIter::iter_type.

Referenced by dbus_message_append_args_valist().

DBUS_EXPORT dbus_bool_t dbus_message_iter_append_basic ( DBusMessageIter iter,
int  type,
const void *  value 
)

Appends a basic-typed value to the message.

The basic types are the non-container types such as integer and string.

The "value" argument should be the address of a basic-typed value. So for string, const char**. For integer, dbus_int32_t*.

For Unix file descriptors this function will internally duplicate the descriptor you passed in. Hence you may close the descriptor immediately after this call.

Todo:
If this fails due to lack of memory, the message is hosed and you have to start over building the whole message.
Parameters
iterthe append iterator
typethe type of the value
valuethe address of the value
Returns
FALSE if not enough memory

Definition at line 2656 of file dbus-message.c.

References _dbus_close(), _dbus_dup(), _dbus_header_set_field_basic(), _dbus_type_writer_write_basic(), DBUS_HEADER_FIELD_UNIX_FDS, DBUS_TYPE_BOOLEAN, dbus_type_is_basic(), DBUS_TYPE_OBJECT_PATH, DBUS_TYPE_SIGNATURE, DBUS_TYPE_STRING, DBUS_TYPE_UINT32, DBUS_TYPE_UNIX_FD, FALSE, header, DBusMessageRealIter::iter_type, DBusMessageRealIter::message, NULL, DBusMessageRealIter::u, and DBusMessageRealIter::writer.

Referenced by dbus_message_append_args_valist(), and dbus_message_new_error().

DBUS_EXPORT dbus_bool_t dbus_message_iter_append_fixed_array ( DBusMessageIter iter,
int  element_type,
const void *  value,
int  n_elements 
)

Appends a block of fixed-length values to an array.

The fixed-length types are all basic types that are not string-like. So int32, double, bool, etc. (Unix file descriptors however are not supported.) You must call dbus_message_iter_open_container() to open an array of values before calling this function. You may call this function multiple times (and intermixed with calls to dbus_message_iter_append_basic()) for the same array.

The "value" argument should be the address of the array. So for integer, "dbus_int32_t**" is expected for example.

Warning
in C, given "int array[]", "&array == array" (the comp.lang.c FAQ says otherwise, but gcc and the FAQ don't agree). So if you're using an array instead of a pointer you have to create a pointer variable, assign the array to it, then take the address of the pointer variable.
1 const dbus_int32_t array[] = { 1, 2, 3 };
2 const dbus_int32_t *v_ARRAY = array;
3 if (!dbus_message_iter_append_fixed_array (&iter, DBUS_TYPE_INT32, &v_ARRAY, 3))
4  fprintf (stderr, "No memory!\n");
For strings it works to write const char *array = "Hello" and then use &array though.
Todo:
If this fails due to lack of memory, the message is hosed and you have to start over building the whole message.
Parameters
iterthe append iterator
element_typethe type of the array elements
valuethe address of the array
n_elementsthe number of elements to append
Returns
FALSE if not enough memory

Definition at line 2791 of file dbus-message.c.

References _dbus_type_get_alignment(), _dbus_type_writer_write_fixed_multi(), DBusTypeWriter::container_type, DBUS_MAXIMUM_ARRAY_LENGTH, DBUS_TYPE_ARRAY, DBUS_TYPE_BOOLEAN, dbus_type_is_fixed(), DBUS_TYPE_UNIX_FD, FALSE, DBusMessageRealIter::iter_type, NULL, DBusMessageRealIter::u, and DBusMessageRealIter::writer.

Referenced by dbus_message_append_args_valist().

DBUS_EXPORT dbus_bool_t dbus_message_iter_close_container ( DBusMessageIter iter,
DBusMessageIter sub 
)

Closes a container-typed value appended to the message; may write out more information to the message known only after the entire container is written, and may free resources created by dbus_message_iter_open_container().

Todo:
If this fails due to lack of memory, the message is hosed and you have to start over building the whole message.
Parameters
iterthe append iterator
subsub-iterator to close
Returns
FALSE if not enough memory

Definition at line 2918 of file dbus-message.c.

References _dbus_type_writer_unrecurse(), FALSE, DBusMessageRealIter::iter_type, DBusMessageRealIter::u, and DBusMessageRealIter::writer.

Referenced by dbus_message_append_args_valist().

DBUS_EXPORT int dbus_message_iter_get_arg_type ( DBusMessageIter iter)

Returns the argument type of the argument that the message iterator points to.

If the iterator is at the end of the message, returns DBUS_TYPE_INVALID. You can thus write a loop as follows:

1 dbus_message_iter_init (message, &iter);
2 while ((current_type = dbus_message_iter_get_arg_type (&iter)) != DBUS_TYPE_INVALID)
3  dbus_message_iter_next (&iter);
Parameters
iterthe message iter
Returns
the argument type

Definition at line 2139 of file dbus-message.c.

References _dbus_type_reader_get_current_type(), DBUS_TYPE_INVALID, FALSE, DBusMessageRealIter::iter_type, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

Referenced by _dbus_message_iter_get_args_valist(), dbus_message_iter_get_basic(), and dbus_message_iter_get_element_type().

DBUS_EXPORT DBUS_DEPRECATED int dbus_message_iter_get_array_len ( DBusMessageIter iter)

Returns the number of bytes in the array as marshaled in the wire protocol.

The iterator must currently be inside an array-typed value.

This function is deprecated on the grounds that it is stupid. Why would you want to know how many bytes are in the array as marshaled in the wire protocol? For now, use the n_elements returned from dbus_message_iter_get_fixed_array() instead, or iterate over the array values and count them.

Todo:
introduce a variant of this get_n_elements that returns the number of elements, though with a non-fixed array it will not be very efficient, so maybe it's not good.
Parameters
iterthe iterator
Returns
the number of bytes in the array

Definition at line 2346 of file dbus-message.c.

References _dbus_type_reader_get_array_length(), DBusMessageRealIter::reader, and DBusMessageRealIter::u.

DBUS_EXPORT void dbus_message_iter_get_basic ( DBusMessageIter iter,
void *  value 
)

Reads a basic-typed value from the message iterator.

Basic types are the non-containers such as integer and string.

The value argument should be the address of a location to store the returned value. So for int32 it should be a "dbus_int32_t*" and for string a "const char**". The returned value is by reference and should not be freed.

This call duplicates Unix file descriptors when reading them. It is your job to close them when you don't need them anymore.

Unix file descriptors that are read with this function will have the FD_CLOEXEC flag set. If you need them without this flag set, make sure to unset it with fcntl().

Be sure you have somehow checked that dbus_message_iter_get_arg_type() matches the type you are expecting, or you'll crash when you try to use an integer as a string or something.

To read any container type (array, struct, dict) you will need to recurse into the container with dbus_message_iter_recurse(). If the container is an array of fixed-length values (except Unix file descriptors), you can get all the array elements at once with dbus_message_iter_get_fixed_array(). Otherwise, you have to iterate over the container's contents one value at a time.

All basic-typed values are guaranteed to fit in a DBusBasicValue, so in versions of libdbus that have that type, you can write code like this:

1 DBusBasicValue value;
2 int type;
3 dbus_message_iter_get_basic (&read_iter, &value);
4 type = dbus_message_iter_get_arg_type (&read_iter);
5 dbus_message_iter_append_basic (&write_iter, type, &value);

(All D-Bus basic types are either numeric and 8 bytes or smaller, or behave like a string; so in older versions of libdbus, DBusBasicValue can be replaced with union { char *string; unsigned char bytes[8]; }, for instance.)

Parameters
iterthe iterator
valuelocation to store the value

Definition at line 2293 of file dbus-message.c.

References _dbus_dup(), _dbus_type_reader_read_basic(), dbus_message_iter_get_arg_type(), DBUS_TYPE_UNIX_FD, DBusMessageRealIter::message, NULL, DBusMessageRealIter::reader, DBusMessageRealIter::u, and DBusBasicValue::u32.

DBUS_EXPORT int dbus_message_iter_get_element_type ( DBusMessageIter iter)

Returns the element type of the array that the message iterator points to.

Note that you need to check that the iterator points to an array prior to using this function.

Parameters
iterthe message iter
Returns
the array element type

Definition at line 2158 of file dbus-message.c.

References _dbus_type_reader_get_element_type(), dbus_message_iter_get_arg_type(), DBUS_TYPE_ARRAY, DBUS_TYPE_INVALID, DBusMessageRealIter::iter_type, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

DBUS_EXPORT void dbus_message_iter_get_fixed_array ( DBusMessageIter iter,
void *  value,
int *  n_elements 
)

Reads a block of fixed-length values from the message iterator.

Fixed-length values are those basic types that are not string-like, such as integers, bool, double. The returned block will be from the current position in the array until the end of the array.

There is one exception here: although DBUS_TYPE_UNIX_FD is considered a 'fixed' type arrays of this type may not be read with this function.

The message iter should be "in" the array (that is, you recurse into the array, and then you call dbus_message_iter_get_fixed_array() on the "sub-iterator" created by dbus_message_iter_recurse()).

The value argument should be the address of a location to store the returned array. So for int32 it should be a "const dbus_int32_t**" The returned value is by reference and should not be freed.

This function should only be used if dbus_type_is_fixed() returns TRUE for the element type.

If an array's elements are not fixed in size, you have to recurse into the array with dbus_message_iter_recurse() and read the elements one by one.

Because the array is not copied, this function runs in constant time and is fast; it's much preferred over walking the entire array with an iterator. (However, you can always use dbus_message_iter_recurse(), even for fixed-length types; dbus_message_iter_get_fixed_array() is just an optimization.)

Parameters
iterthe iterator
valuelocation to store the block
n_elementsnumber of elements in the block

Definition at line 2391 of file dbus-message.c.

References _dbus_type_reader_get_current_type(), _dbus_type_reader_read_fixed_multi(), DBUS_TYPE_INVALID, dbus_type_is_fixed(), DBUS_TYPE_UNIX_FD, NULL, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

DBUS_EXPORT char * dbus_message_iter_get_signature ( DBusMessageIter iter)

Returns the current signature of a message iterator.

This is useful primarily for dealing with variants; one can recurse into a variant and determine the signature of the variant's value.

The returned string must be freed with dbus_free().

Parameters
iterthe message iterator
Returns
the contained signature, or NULL if out of memory

Definition at line 2220 of file dbus-message.c.

References _dbus_string_append_len(), _dbus_string_free(), _dbus_string_get_const_data(), _dbus_string_init(), _dbus_string_steal_data(), _dbus_type_reader_get_signature(), NULL, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

DBUS_EXPORT dbus_bool_t dbus_message_iter_has_next ( DBusMessageIter iter)

Checks if an iterator has any more fields.

Parameters
iterthe message iter
Returns
TRUE if there are more fields following

Definition at line 2095 of file dbus-message.c.

References _dbus_type_reader_has_next(), FALSE, DBusMessageRealIter::iter_type, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

DBUS_EXPORT dbus_bool_t dbus_message_iter_init ( DBusMessage message,
DBusMessageIter iter 
)

Initializes a DBusMessageIter for reading the arguments of the message passed in.

When possible, dbus_message_get_args() is much more convenient. Some types of argument can only be read with DBusMessageIter however.

The easiest way to iterate is like this:

1 dbus_message_iter_init (message, &iter);
2 while ((current_type = dbus_message_iter_get_arg_type (&iter)) != DBUS_TYPE_INVALID)
3  dbus_message_iter_next (&iter);

DBusMessageIter contains no allocated memory; it need not be freed, and can be copied by assignment or memcpy().

Parameters
messagethe message
iterpointer to an iterator to initialize
Returns
FALSE if the message has no arguments

Definition at line 2064 of file dbus-message.c.

References _dbus_header_get_byte_order(), _dbus_type_reader_get_current_type(), _dbus_type_reader_init(), body, DBUS_TYPE_INVALID, FALSE, header, NULL, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

Referenced by dbus_message_get_args_valist().

DBUS_EXPORT void dbus_message_iter_init_append ( DBusMessage message,
DBusMessageIter iter 
)

Initializes a DBusMessageIter for appending arguments to the end of a message.

Todo:
If appending any of the arguments fails due to lack of memory, the message is hosed and you have to start over building the whole message.
Parameters
messagethe message
iterpointer to an iterator to initialize

Definition at line 2421 of file dbus-message.c.

References _dbus_header_get_byte_order(), _dbus_string_get_length(), _dbus_type_writer_init_types_delayed(), body, header, NULL, DBusMessageRealIter::u, and DBusMessageRealIter::writer.

Referenced by dbus_message_append_args_valist(), and dbus_message_new_error().

DBUS_EXPORT dbus_bool_t dbus_message_iter_next ( DBusMessageIter iter)

Moves the iterator to the next field, if any.

If there's no next field, returns FALSE. If the iterator moves forward, returns TRUE.

Parameters
iterthe message iter
Returns
TRUE if the iterator was moved to the next field

Definition at line 2114 of file dbus-message.c.

References _dbus_type_reader_next(), FALSE, DBusMessageRealIter::iter_type, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

DBUS_EXPORT dbus_bool_t dbus_message_iter_open_container ( DBusMessageIter iter,
int  type,
const char *  contained_signature,
DBusMessageIter sub 
)

Appends a container-typed value to the message; you are required to append the contents of the container using the returned sub-iterator, and then call dbus_message_iter_close_container().

Container types are for example struct, variant, and array. For variants, the contained_signature should be the type of the single value inside the variant. For structs and dict entries, contained_signature should be NULL; it will be set to whatever types you write into the struct. For arrays, contained_signature should be the type of the array elements.

Todo:
If this fails due to lack of memory, the message is hosed and you have to start over building the whole message.
Parameters
iterthe append iterator
typethe type of the value
contained_signaturethe type of container contents
subsub-iterator to initialize
Returns
FALSE if not enough memory

Definition at line 2849 of file dbus-message.c.

References _dbus_string_init_const(), _dbus_type_writer_recurse(), DBUS_DICT_ENTRY_BEGIN_CHAR, DBUS_TYPE_ARRAY, DBUS_TYPE_DICT_ENTRY, dbus_type_is_container(), DBUS_TYPE_STRUCT, DBUS_TYPE_VARIANT, FALSE, DBusMessageRealIter::iter_type, NULL, DBusMessageRealIter::u, and DBusMessageRealIter::writer.

Referenced by dbus_message_append_args_valist().

DBUS_EXPORT void dbus_message_iter_recurse ( DBusMessageIter iter,
DBusMessageIter sub 
)

Recurses into a container value when reading values from a message, initializing a sub-iterator to use for traversing the child values of the container.

Note that this recurses into a value, not a type, so you can only recurse if the value exists. The main implication of this is that if you have for example an empty array of array of int32, you can recurse into the outermost array, but it will have no values, so you won't be able to recurse further. There's no array of int32 to recurse into.

If a container is an array of fixed-length types (except Unix file descriptors), it is much more efficient to use dbus_message_iter_get_fixed_array() to get the whole array in one shot, rather than individually walking over the array elements.

Be sure you have somehow checked that dbus_message_iter_get_arg_type() matches the type you are expecting to recurse into. Results of this function are undefined if there is no container to recurse into at the current iterator position.

Parameters
iterthe message iterator
subthe sub-iterator to initialize

Definition at line 2195 of file dbus-message.c.

References _dbus_type_reader_recurse(), NULL, DBusMessageRealIter::reader, and DBusMessageRealIter::u.

DBUS_EXPORT void dbus_message_lock ( DBusMessage message)

Locks a message.

Allows checking that applications don't keep a reference to a message in the outgoing queue and change it underneath us. Messages are locked when they enter the outgoing queue (dbus_connection_send_message()), and the library complains if the message is modified while locked. This function may also called externally, for applications wrapping D-Bus in another protocol.

Parameters
messagethe message to lock.

Definition at line 384 of file dbus-message.c.

References _dbus_assert, _dbus_header_update_lengths(), _dbus_string_get_length(), body, dbus_message_get_signature(), header, locked, NULL, and TRUE.

Referenced by dbus_message_marshal().

DBUS_EXPORT dbus_bool_t dbus_message_marshal ( DBusMessage msg,
char **  marshalled_data_p,
int *  len_p 
)

Turn a DBusMessage into the marshalled form as described in the D-Bus specification.

Generally, this function is only useful for encapsulating D-Bus messages in a different protocol.

Parameters
msgthe DBusMessage
marshalled_data_pthe location to save the marshalled form to
len_pthe location to save the length of the marshalled form to
Returns
FALSE if there was not enough memory

Definition at line 4721 of file dbus-message.c.

References _dbus_string_copy(), _dbus_string_free(), _dbus_string_get_length(), _dbus_string_init(), _dbus_string_steal_data(), body, DBusHeader::data, dbus_message_lock(), FALSE, header, locked, NULL, and TRUE.

DBUS_EXPORT DBusMessage * dbus_message_new ( int  message_type)

Constructs a new message of the given message type.

Types include DBUS_MESSAGE_TYPE_METHOD_CALL, DBUS_MESSAGE_TYPE_SIGNAL, and so forth.

Usually you want to use dbus_message_new_method_call(), dbus_message_new_method_return(), dbus_message_new_signal(), or dbus_message_new_error() instead.

Parameters
message_typetype of message
Returns
new message or NULL if no memory

Definition at line 1289 of file dbus-message.c.

References _dbus_header_create(), DBUS_MESSAGE_TYPE_INVALID, dbus_message_unref(), header, and NULL.

DBUS_EXPORT DBusMessage * dbus_message_new_error ( DBusMessage reply_to,
const char *  error_name,
const char *  error_message 
)

Creates a new message that is an error reply to another message.

Error replies are most common in response to method calls, but can be returned in reply to any message.

The error name must be a valid error name according to the syntax given in the D-Bus specification. If you don't want to make up an error name just use DBUS_ERROR_FAILED.

Parameters
reply_tothe message we're replying to
error_namethe error name
error_messagethe error message string (or NULL for none, but please give a message)
Returns
a new error message object, free with dbus_message_unref()

Definition at line 1470 of file dbus-message.c.

References _dbus_header_create(), dbus_message_get_sender(), dbus_message_get_serial(), dbus_message_iter_append_basic(), dbus_message_iter_init_append(), dbus_message_set_no_reply(), dbus_message_set_reply_serial(), DBUS_MESSAGE_TYPE_ERROR, dbus_message_unref(), DBUS_TYPE_STRING, header, NULL, and TRUE.

Referenced by _dbus_pending_call_set_timeout_error_unlocked(), dbus_connection_dispatch(), and dbus_message_new_error_printf().

DBUS_EXPORT DBusMessage * dbus_message_new_error_printf ( DBusMessage reply_to,
const char *  error_name,
const char *  error_format,
  ... 
)

Creates a new message that is an error reply to another message, allowing you to use printf formatting.

See dbus_message_new_error() for details - this function is the same aside from the printf formatting.

Todo:
add _DBUS_GNUC_PRINTF to this (requires moving _DBUS_GNUC_PRINTF to public header, see DBUS_DEPRECATED for an example)
Parameters
reply_tothe original message
error_namethe error name
error_formatthe error message format as with printf
...format string arguments
Returns
a new error message

Definition at line 1542 of file dbus-message.c.

References _dbus_string_append_printf_valist(), _dbus_string_free(), _dbus_string_get_const_data(), _dbus_string_init(), dbus_message_new_error(), and NULL.

DBUS_EXPORT DBusMessage * dbus_message_new_method_call ( const char *  destination,
const char *  path,
const char *  iface,
const char *  method 
)

Constructs a new message to invoke a method on a remote object.

Returns NULL if memory can't be allocated for the message. The destination may be NULL in which case no destination is set; this is appropriate when using D-Bus in a peer-to-peer context (no message bus). The interface may be NULL, which means that if multiple methods with the given name exist it is undefined which one will be invoked.

The path and method names may not be NULL.

Destination, path, interface, and method name can't contain any invalid characters (see the D-Bus specification).

Parameters
destinationname that the message should be sent to or NULL
pathobject path the message should be sent to
ifaceinterface to invoke method on, or NULL
methodmethod to invoke
Returns
a new DBusMessage, free with dbus_message_unref()

Definition at line 1333 of file dbus-message.c.

References _dbus_header_create(), DBUS_MESSAGE_TYPE_METHOD_CALL, dbus_message_unref(), header, and NULL.

Referenced by dbus_bus_add_match(), dbus_bus_get_id(), dbus_bus_get_unix_user(), dbus_bus_name_has_owner(), dbus_bus_register(), dbus_bus_release_name(), dbus_bus_remove_match(), dbus_bus_request_name(), and dbus_bus_start_service_by_name().

DBUS_EXPORT DBusMessage * dbus_message_new_method_return ( DBusMessage method_call)

Constructs a message that is a reply to a method call.

Returns NULL if memory can't be allocated for the message.

Parameters
method_callthe message being replied to
Returns
a new DBusMessage, free with dbus_message_unref()

Definition at line 1373 of file dbus-message.c.

References _dbus_header_create(), dbus_message_get_sender(), dbus_message_get_serial(), dbus_message_set_no_reply(), dbus_message_set_reply_serial(), DBUS_MESSAGE_TYPE_METHOD_RETURN, dbus_message_unref(), header, NULL, and TRUE.

DBUS_EXPORT DBusMessage * dbus_message_new_signal ( const char *  path,
const char *  iface,
const char *  name 
)

Constructs a new message representing a signal emission.

Returns NULL if memory can't be allocated for the message. A signal is identified by its originating object path, interface, and the name of the signal.

Path, interface, and signal name must all be valid (the D-Bus specification defines the syntax of these fields).

Parameters
paththe path to the object emitting the signal
ifacethe interface the signal is emitted from
namename of the signal
Returns
a new DBusMessage, free with dbus_message_unref()

Definition at line 1424 of file dbus-message.c.

References _dbus_header_create(), dbus_message_set_no_reply(), DBUS_MESSAGE_TYPE_SIGNAL, dbus_message_unref(), header, NULL, and TRUE.

Referenced by _dbus_connection_new_for_transport().

DBUS_EXPORT DBusMessage * dbus_message_ref ( DBusMessage message)

Increments the reference count of a DBusMessage.

Parameters
messagethe message
Returns
the message
See also
dbus_message_unref

Definition at line 1667 of file dbus-message.c.

References _dbus_assert, _dbus_atomic_inc(), _dbus_current_generation, generation, in_cache, NULL, and refcount.

Referenced by _dbus_pending_call_set_reply_unlocked().

DBUS_EXPORT void dbus_message_set_allow_interactive_authorization ( DBusMessage message,
dbus_bool_t  allow 
)

Sets a flag indicating that the caller of the method is prepared to wait for interactive authorization to take place (for instance via Polkit) before the actual method is processed.

The flag is FALSE by default; that is, by default the other end is expected to make any authorization decisions non-interactively and promptly. It may use the error DBUS_ERROR_INTERACTIVE_AUTHORIZATION_REQUIRED to signal that authorization failed, but could have succeeded if this flag had been used.

For messages whose type is not DBUS_MESSAGE_TYPE_METHOD_CALL, this flag is meaningless and should not be set.

On the protocol level this toggles DBUS_HEADER_FLAG_ALLOW_INTERACTIVE_AUTHORIZATION.

Parameters
messagethe message
allowTRUE if interactive authorization is acceptable

Definition at line 4901 of file dbus-message.c.

References _dbus_header_toggle_flag(), DBUS_HEADER_FLAG_ALLOW_INTERACTIVE_AUTHORIZATION, header, locked, and NULL.

DBUS_EXPORT void dbus_message_set_auto_start ( DBusMessage message,
dbus_bool_t  auto_start 
)

Sets a flag indicating that an owner for the destination name will be automatically started before the message is delivered.

When this flag is set, the message is held until a name owner finishes starting up, or fails to start up. In case of failure, the reply will be an error.

The flag is set to TRUE by default, i.e. auto starting is the default.

On the protocol level this toggles DBUS_HEADER_FLAG_NO_AUTO_START

Parameters
messagethe message
auto_startTRUE if auto-starting is desired

Definition at line 3026 of file dbus-message.c.

References _dbus_header_toggle_flag(), DBUS_HEADER_FLAG_NO_AUTO_START, header, locked, and NULL.

DBUS_EXPORT dbus_bool_t dbus_message_set_data ( DBusMessage message,
dbus_int32_t  slot,
void *  data,
DBusFreeFunction  free_data_func 
)

Stores a pointer on a DBusMessage, along with an optional function to be used for freeing the data when the data is set again, or when the message is finalized.

The slot number must have been allocated with dbus_message_allocate_data_slot().

Parameters
messagethe message
slotthe slot number
datathe data to store
free_data_funcfinalizer function for the data
Returns
TRUE if there was enough memory to store the data

Definition at line 4599 of file dbus-message.c.

References _dbus_data_slot_list_set(), FALSE, NULL, and slot_list.

DBUS_EXPORT dbus_bool_t dbus_message_set_destination ( DBusMessage message,
const char *  destination 
)

Sets the message's destination.

The destination is the name of another connection on the bus and may be either the unique name assigned by the bus to each connection, or a well-known name specified in advance.

The destination name must contain only valid characters as defined in the D-Bus specification.

Parameters
messagethe message
destinationthe destination name or NULL to unset
Returns
FALSE if not enough memory

Definition at line 3425 of file dbus-message.c.

References DBUS_HEADER_FIELD_DESTINATION, DBUS_TYPE_STRING, FALSE, locked, and NULL.

DBUS_EXPORT dbus_bool_t dbus_message_set_error_name ( DBusMessage message,
const char *  error_name 
)

Sets the name of the error (DBUS_MESSAGE_TYPE_ERROR).

The name is fully-qualified (namespaced).

The error name must contain only valid characters as defined in the D-Bus specification.

Parameters
messagethe message
error_namethe name or NULL to unset
Returns
FALSE if not enough memory

Definition at line 3371 of file dbus-message.c.

References DBUS_HEADER_FIELD_ERROR_NAME, DBUS_TYPE_STRING, FALSE, locked, and NULL.

DBUS_EXPORT dbus_bool_t dbus_message_set_interface ( DBusMessage message,
const char *  iface 
)

Sets the interface this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or the interface a signal is being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL).

The interface name must contain only valid characters as defined in the D-Bus specification.

Parameters
messagethe message
ifacethe interface or NULL to unset
Returns
FALSE if not enough memory

Definition at line 3198 of file dbus-message.c.

References DBUS_HEADER_FIELD_INTERFACE, DBUS_TYPE_STRING, FALSE, locked, and NULL.

DBUS_EXPORT dbus_bool_t dbus_message_set_member ( DBusMessage message,
const char *  member 
)

Sets the interface member being invoked (DBUS_MESSAGE_TYPE_METHOD_CALL) or emitted (DBUS_MESSAGE_TYPE_SIGNAL).

The member name must contain only valid characters as defined in the D-Bus specification.

Parameters
messagethe message
memberthe member or NULL to unset
Returns
FALSE if not enough memory

Definition at line 3286 of file dbus-message.c.

References DBUS_HEADER_FIELD_MEMBER, DBUS_TYPE_STRING, FALSE, locked, and NULL.

DBUS_EXPORT void dbus_message_set_no_reply ( DBusMessage message,
dbus_bool_t  no_reply 
)

Sets a flag indicating that the message does not want a reply; if this flag is set, the other end of the connection may (but is not required to) optimize by not sending method return or error replies.

If this flag is set, there is no way to know whether the message successfully arrived at the remote end. Normally you know a message was received when you receive the reply to it.

The flag is FALSE by default, that is by default the other end is required to reply.

On the protocol level this toggles DBUS_HEADER_FLAG_NO_REPLY_EXPECTED

Parameters
messagethe message
no_replyTRUE if no reply is desired

Definition at line 2984 of file dbus-message.c.

References _dbus_header_toggle_flag(), DBUS_HEADER_FLAG_NO_REPLY_EXPECTED, header, locked, and NULL.

Referenced by dbus_message_new_error(), dbus_message_new_method_return(), and dbus_message_new_signal().

DBUS_EXPORT dbus_bool_t dbus_message_set_path ( DBusMessage message,
const char *  object_path 
)

Sets the object path this message is being sent to (for DBUS_MESSAGE_TYPE_METHOD_CALL) or the one a signal is being emitted from (for DBUS_MESSAGE_TYPE_SIGNAL).

The path must contain only valid characters as defined in the D-Bus specification.

Parameters
messagethe message
object_paththe path or NULL to unset
Returns
FALSE if not enough memory

Definition at line 3067 of file dbus-message.c.

References DBUS_HEADER_FIELD_PATH, DBUS_TYPE_OBJECT_PATH, FALSE, locked, and NULL.

DBUS_EXPORT dbus_bool_t dbus_message_set_reply_serial ( DBusMessage message,
dbus_uint32_t  reply_serial 
)

Sets the reply serial of a message (the serial of the message this is a reply to).

Parameters
messagethe message
reply_serialthe serial we're replying to
Returns
FALSE if not enough memory

Definition at line 1143 of file dbus-message.c.

References _dbus_header_set_field_basic(), DBUS_HEADER_FIELD_REPLY_SERIAL, DBUS_TYPE_UINT32, FALSE, header, locked, and NULL.

Referenced by dbus_message_new_error(), and dbus_message_new_method_return().

DBUS_EXPORT dbus_bool_t dbus_message_set_sender ( DBusMessage message,
const char *  sender 
)

Sets the message sender.

The sender must be a valid bus name as defined in the D-Bus specification.

Usually you don't want to call this. The message bus daemon will call it to set the origin of each message. If you aren't implementing a message bus daemon you shouldn't need to set the sender.

Parameters
messagethe message
senderthe sender or NULL to unset
Returns
FALSE if not enough memory

Definition at line 3479 of file dbus-message.c.

References DBUS_HEADER_FIELD_SENDER, DBUS_TYPE_STRING, FALSE, locked, and NULL.

DBUS_EXPORT void dbus_message_set_serial ( DBusMessage message,
dbus_uint32_t  serial 
)

Sets the serial number of a message.

This can only be done once on a message.

DBusConnection will automatically set the serial to an appropriate value when the message is sent; this function is only needed when encapsulating messages in another protocol, or otherwise bypassing DBusConnection.

Parameters
messagethe message
serialthe serial

Definition at line 254 of file dbus-message.c.

References _dbus_header_set_serial(), header, locked, and NULL.

Referenced by dbus_connection_send_with_reply().

DBUS_EXPORT int dbus_message_type_from_string ( const char *  type_str)

Utility function to convert a machine-readable (not translated) string into a D-Bus message type.

1 "method_call" -> DBUS_MESSAGE_TYPE_METHOD_CALL
2 "method_return" -> DBUS_MESSAGE_TYPE_METHOD_RETURN
3 "signal" -> DBUS_MESSAGE_TYPE_SIGNAL
4 "error" -> DBUS_MESSAGE_TYPE_ERROR
5 anything else -> DBUS_MESSAGE_TYPE_INVALID

Definition at line 4663 of file dbus-message.c.

References DBUS_MESSAGE_TYPE_ERROR, DBUS_MESSAGE_TYPE_INVALID, DBUS_MESSAGE_TYPE_METHOD_CALL, DBUS_MESSAGE_TYPE_METHOD_RETURN, and DBUS_MESSAGE_TYPE_SIGNAL.

DBUS_EXPORT const char* dbus_message_type_to_string ( int  type)

Utility function to convert a D-Bus message type into a machine-readable string (not translated).

1 DBUS_MESSAGE_TYPE_METHOD_CALL -> "method_call"
2 DBUS_MESSAGE_TYPE_METHOD_RETURN -> "method_return"
3 DBUS_MESSAGE_TYPE_SIGNAL -> "signal"
4 DBUS_MESSAGE_TYPE_ERROR -> "error"
5 DBUS_MESSAGE_TYPE_INVALID -> "invalid"

Definition at line 4691 of file dbus-message.c.

References DBUS_MESSAGE_TYPE_ERROR, DBUS_MESSAGE_TYPE_METHOD_CALL, DBUS_MESSAGE_TYPE_METHOD_RETURN, and DBUS_MESSAGE_TYPE_SIGNAL.

Referenced by _dbus_connection_message_sent_unlocked(), _dbus_connection_queue_received_message_link(), and dbus_connection_dispatch().

DBUS_EXPORT void dbus_message_unref ( DBusMessage message)
DBUS_EXPORT dbus_bool_t dbus_set_error_from_message ( DBusError error,
DBusMessage message 
)

Sets a DBusError based on the contents of the given message.

The error is only set if the message is an error message, as in DBUS_MESSAGE_TYPE_ERROR. The name of the error is set to the name of the message, and the error message is set to the first argument if the argument exists and is a string.

The return value indicates whether the error was set (the error is set if and only if the message is an error message). So you can check for an error reply and convert it to DBusError in one go:

1 if (dbus_set_error_from_message (error, reply))
2  return error;
3 else
4  process reply;
Parameters
errorthe error to set
messagethe message to set it from
Returns
TRUE if the message had type DBUS_MESSAGE_TYPE_ERROR

Definition at line 3796 of file dbus-message.c.

References dbus_message_get_args(), dbus_message_get_error_name(), dbus_message_get_type(), DBUS_MESSAGE_TYPE_ERROR, dbus_set_error(), DBUS_TYPE_INVALID, DBUS_TYPE_STRING, FALSE, NULL, and TRUE.

Referenced by dbus_bus_get_id(), dbus_bus_get_unix_user(), dbus_bus_register(), dbus_bus_release_name(), dbus_bus_request_name(), dbus_bus_start_service_by_name(), and dbus_connection_send_with_reply_and_block().