wl_proxy(3) Wayland wl_proxy(3)
NAME
wl_proxy - Represents a protocol object on the client side.
SYNOPSIS
#include <wayland-client-core.h>
Public Member Functions
struct wl_proxy * wl_proxy_create (struct wl_proxy *factory, const
struct wl_interface *interface)
void wl_proxy_destroy (struct wl_proxy *proxy)
int wl_proxy_add_listener (struct wl_proxy *proxy,
void(**implementation)(void), void *data)
const void * wl_proxy_get_listener (struct wl_proxy *proxy)
int wl_proxy_add_dispatcher (struct wl_proxy *proxy,
wl_dispatcher_func_t dispatcher, const void *implementation, void
*data)
struct wl_proxy * wl_proxy_marshal_array_constructor (struct wl_proxy
*proxy, uint32_t opcode, union wl_argument *args, const struct
wl_interface *interface)
struct wl_proxy * wl_proxy_marshal_array_constructor_versioned (struct
wl_proxy *proxy, uint32_t opcode, union wl_argument *args, const
struct wl_interface *interface, uint32_t version)
struct wl_proxy * wl_proxy_marshal_flags (struct wl_proxy *proxy,
uint32_t opcode, const struct wl_interface *interface, uint32_t
version, uint32_t flags,...)
struct wl_proxy * wl_proxy_marshal_array_flags (struct wl_proxy *proxy,
uint32_t opcode, const struct wl_interface *interface, uint32_t
version, uint32_t flags, union wl_argument *args)
void wl_proxy_marshal (struct wl_proxy *proxy, uint32_t opcode,...)
struct wl_proxy * wl_proxy_marshal_constructor (struct wl_proxy *proxy,
uint32_t opcode, const struct wl_interface *interface,...)
struct wl_proxy * wl_proxy_marshal_constructor_versioned (struct
wl_proxy *proxy, uint32_t opcode, const struct wl_interface
*interface, uint32_t version,...)
void wl_proxy_marshal_array (struct wl_proxy *proxy, uint32_t opcode,
union wl_argument *args)
void wl_proxy_set_user_data (struct wl_proxy *proxy, void *user_data)
void * wl_proxy_get_user_data (struct wl_proxy *proxy)
uint32_t wl_proxy_get_version (struct wl_proxy *proxy)
uint32_t wl_proxy_get_id (struct wl_proxy *proxy)
void wl_proxy_set_tag (struct wl_proxy *proxy, const char *const *tag)
const char *const * wl_proxy_get_tag (struct wl_proxy *proxy)
const char * wl_proxy_get_class (struct wl_proxy *proxy)
struct wl_display * wl_proxy_get_display (struct wl_proxy *proxy)
void wl_proxy_set_queue (struct wl_proxy *proxy, struct wl_event_queue
*queue)
const char * wl_event_queue_get_name (const struct wl_event_queue
*queue)
void * wl_proxy_create_wrapper (void *proxy)
void wl_proxy_wrapper_destroy (void *proxy_wrapper)
Related Symbols
(Note that these are not member symbols.)
#define WL_MARSHAL_FLAG_DESTROY (1 << 0)
Detailed Description
Represents a protocol object on the client side.
A wl_proxy acts as a client side proxy to an object existing in the
compositor. The proxy is responsible for converting requests made by the
clients with wl_proxy_marshal() into Wayland's wire format. Events
coming from the compositor are also handled by the proxy, which will in
turn call the handler set with wl_proxy_add_listener().
Note
With the exception of function wl_proxy_set_queue(), functions
accessing a wl_proxy are not normally used by client code. Clients
should normally use the higher level interface generated by the
scanner to interact with compositor objects.
Member Function Documentation
const char * wl_event_queue_get_name (const struct wl_event_queue * queue)
Get the name of an event queue
Parameters
queue The queue to query
Return the human readable name for the event queue
This may be NULL if no name has been set.
int wl_proxy_add_dispatcher (struct wl_proxy * proxy, wl_dispatcher_func_t
dispatcher, const void * implementation, void * data)
Set a proxy's listener (with dispatcher)
Parameters
proxy The proxy object
dispatcher The dispatcher to be used for this proxy
implementation The dispatcher-specific listener implementation
data User data to be associated with the proxy
Returns
0 on success or -1 on failure
Set proxy's listener to use dispatcher_func as its dispatcher and
dispatcher_data as its dispatcher-specific implementation and its user
data to data. If a listener has already been set, this function fails
and nothing is changed.
The exact details of dispatcher_data depend on the dispatcher used. This
function is intended to be used by language bindings, not user code.
proxy must not be a proxy wrapper.
int wl_proxy_add_listener (struct wl_proxy * proxy, void(**)(void)
implementation, void * data)
Set a proxy's listener
Parameters
proxy The proxy object
implementation The listener to be added to proxy
data User data to be associated with the proxy
Returns
0 on success or -1 on failure
Set proxy's listener to implementation and its user data to data. If a
listener has already been set, this function fails and nothing is
changed.
implementation is a vector of function pointers. For an opcode n,
implementation[n] should point to the handler of n for the given object.
proxy must not be a proxy wrapper.
struct wl_proxy * wl_proxy_create (struct wl_proxy * factory, const struct
wl_interface * interface)
Create a proxy object with a given interface
Parameters
factory Factory proxy object
interface Interface the proxy object should use
Returns
A newly allocated proxy object or NULL on failure
This function creates a new proxy object with the supplied interface.
The proxy object will have an id assigned from the client id space. The
id should be created on the compositor side by sending an appropriate
request with wl_proxy_marshal().
The proxy will inherit the display and event queue of the factory
object.
Note
This should not normally be used by non-generated code.
See also
wl_display, wl_event_queue, wl_proxy_marshal()
void * wl_proxy_create_wrapper (void * proxy)
Create a proxy wrapper for making queue assignments thread-safe
Parameters
proxy The proxy object to be wrapped
Returns
A proxy wrapper for the given proxy or NULL on failure
A proxy wrapper is type of 'struct wl_proxy' instance that can be used
when sending requests instead of using the original proxy. A proxy
wrapper does not have an implementation or dispatcher, and events
received on the object is still emitted on the original proxy. Trying to
set an implementation or dispatcher will have no effect but result in a
warning being logged.
Setting the proxy queue of the proxy wrapper will make new objects
created using the proxy wrapper use the set proxy queue. Even though
there is no implementation nor dispatcher, the proxy queue can be
changed. This will affect the default queue of new objects created by
requests sent via the proxy wrapper.
A proxy wrapper can only be destroyed using wl_proxy_wrapper_destroy().
A proxy wrapper must be destroyed before the proxy it was created from.
If a user reads and dispatches events on more than one thread, it is
necessary to use a proxy wrapper when sending requests on objects when
the intention is that a newly created proxy is to use a proxy queue
different from the proxy the request was sent on, as creating the new
proxy and then setting the queue is not thread safe.
For example, a module that runs using its own proxy queue that needs to
do display roundtrip must wrap the wl_display proxy object before
sending the wl_display.sync request. For example:
struct wl_event_queue *queue = ...;
struct wl_display *wrapped_display;
struct wl_callback *callback;
wrapped_display = wl_proxy_create_wrapper(display);
wl_proxy_set_queue((struct wl_proxy *) wrapped_display, queue);
callback = wl_display_sync(wrapped_display);
wl_proxy_wrapper_destroy(wrapped_display);
wl_callback_add_listener(callback, ...);
void wl_proxy_destroy (struct wl_proxy * proxy)
Destroy a proxy object
Parameters
proxy The proxy to be destroyed
proxy must not be a proxy wrapper.
Note
This function will abort in response to egregious errors, and will
do so with the display lock held. This means SIGABRT handlers must
not perform any actions that would attempt to take that lock, or a
deadlock would occur.
const char * wl_proxy_get_class (struct wl_proxy * proxy)
Get the interface name (class) of a proxy object
Parameters
proxy The proxy object
Returns
The interface name of the object associated with the proxy
struct wl_display * wl_proxy_get_display (struct wl_proxy * proxy)
Get the display of a proxy object
Parameters
proxy The proxy object
Returns
The wl_display the proxy is associated with
Since
1.23
uint32_t wl_proxy_get_id (struct wl_proxy * proxy)
Get the id of a proxy object
Parameters
proxy The proxy object
Returns
The id the object associated with the proxy
const void * wl_proxy_get_listener (struct wl_proxy * proxy)
Get a proxy's listener
Parameters
proxy The proxy object
Returns
The address of the proxy's listener or NULL if no listener is set
Gets the address to the proxy's listener; which is the listener set with
wl_proxy_add_listener.
This function is useful in clients with multiple listeners on the same
interface to allow the identification of which code to execute.
const char *const * wl_proxy_get_tag (struct wl_proxy * proxy)
Get the tag of a proxy object
See wl_proxy_set_tag for details.
Parameters
proxy The proxy object
Since
1.17.90
void * wl_proxy_get_user_data (struct wl_proxy * proxy)
Get the user data associated with a proxy
Parameters
proxy The proxy object
Returns
The user data associated with proxy
uint32_t wl_proxy_get_version (struct wl_proxy * proxy)
Get the protocol object version of a proxy object
Parameters
proxy The proxy object
Returns
The protocol object version of the proxy or 0
Gets the protocol object version of a proxy object, or 0 if the proxy
was created with unversioned API.
A returned value of 0 means that no version information is available, so
the caller must make safe assumptions about the object's real version.
wl_display's version will always return 0.
void wl_proxy_marshal (struct wl_proxy * proxy, uint32_t opcode, ...)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
... Extra arguments for the given request
This function is similar to wl_proxy_marshal_constructor(), except it
doesn't create proxies for new-id arguments.
Note
This should not normally be used by non-generated code.
See also
wl_proxy_create()
void wl_proxy_marshal_array (struct wl_proxy * proxy, uint32_t opcode, union
wl_argument * args)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
args Extra arguments for the given request
This function is similar to wl_proxy_marshal_array_constructor(), except
it doesn't create proxies for new-id arguments.
Note
This is intended to be used by language bindings and not in non-
generated code.
See also
wl_proxy_marshal()
struct wl_proxy * wl_proxy_marshal_array_constructor (struct wl_proxy *
proxy, uint32_t opcode, union wl_argument * args, const struct
wl_interface * interface)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
args Extra arguments for the given request
interface The interface to use for the new proxy
This function translates a request given an opcode, an interface and a
wl_argument array to the wire format and writes it to the connection
buffer.
For new-id arguments, this function will allocate a new wl_proxy and
send the ID to the server. The new wl_proxy will be returned on success
or NULL on error with errno set accordingly. The newly created proxy
will inherit their version from their parent.
Note
This is intended to be used by language bindings and not in non-
generated code.
See also
wl_proxy_marshal()
struct wl_proxy * wl_proxy_marshal_array_constructor_versioned (struct
wl_proxy * proxy, uint32_t opcode, union wl_argument * args, const
struct wl_interface * interface, uint32_t version)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
args Extra arguments for the given request
interface The interface to use for the new proxy
version The protocol object version for the new proxy
Translates the request given by opcode and the extra arguments into the
wire format and write it to the connection buffer. This version takes an
array of the union type wl_argument.
For new-id arguments, this function will allocate a new wl_proxy and
send the ID to the server. The new wl_proxy will be returned on success
or NULL on error with errno set accordingly. The newly created proxy
will have the version specified.
Note
This is intended to be used by language bindings and not in non-
generated code.
See also
wl_proxy_marshal()
struct wl_proxy * wl_proxy_marshal_array_flags (struct wl_proxy * proxy,
uint32_t opcode, const struct wl_interface * interface, uint32_t
version, uint32_t flags, union wl_argument * args)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
interface The interface to use for the new proxy
version The protocol object version for the new proxy
flags Flags that modify marshalling behaviour
args Extra arguments for the given request
Translates the request given by opcode and the extra arguments into the
wire format and write it to the connection buffer. This version takes an
array of the union type wl_argument.
For new-id arguments, this function will allocate a new wl_proxy and
send the ID to the server. The new wl_proxy will be returned on success
or NULL on error with errno set accordingly. The newly created proxy
will have the version specified.
The flag WL_MARSHAL_FLAG_DESTROY may be passed to ensure the proxy is
destroyed atomically with the marshalling in order to prevent races that
can occur if the display lock is dropped between the marshal and destroy
operations.
Note
This is intended to be used by language bindings and not in non-
generated code.
See also
wl_proxy_marshal_flags()
struct wl_proxy * wl_proxy_marshal_constructor (struct wl_proxy * proxy,
uint32_t opcode, const struct wl_interface * interface, ...)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
interface The interface to use for the new proxy
... Extra arguments for the given request
Returns
A new wl_proxy for the new_id argument or NULL on error
This function translates a request given an opcode, an interface and
extra arguments to the wire format and writes it to the connection
buffer. The types of the extra arguments must correspond to the argument
types of the method associated with the opcode in the interface.
For new-id arguments, this function will allocate a new wl_proxy and
send the ID to the server. The new wl_proxy will be returned on success
or NULL on error with errno set accordingly. The newly created proxy
will inherit their version from their parent.
Note
This should not normally be used by non-generated code.
struct wl_proxy * wl_proxy_marshal_constructor_versioned (struct wl_proxy *
proxy, uint32_t opcode, const struct wl_interface * interface, uint32_t
version, ...)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
interface The interface to use for the new proxy
version The protocol object version of the new proxy
... Extra arguments for the given request
Returns
A new wl_proxy for the new_id argument or NULL on error
Translates the request given by opcode and the extra arguments into the
wire format and write it to the connection buffer.
For new-id arguments, this function will allocate a new wl_proxy and
send the ID to the server. The new wl_proxy will be returned on success
or NULL on error with errno set accordingly. The newly created proxy
will have the version specified.
Note
This should not normally be used by non-generated code.
struct wl_proxy * wl_proxy_marshal_flags (struct wl_proxy * proxy, uint32_t
opcode, const struct wl_interface * interface, uint32_t version,
uint32_t flags, ...)
Prepare a request to be sent to the compositor
Parameters
proxy The proxy object
opcode Opcode of the request to be sent
interface The interface to use for the new proxy
version The protocol object version of the new proxy
flags Flags that modify marshalling behaviour
... Extra arguments for the given request
Returns
A new wl_proxy for the new_id argument or NULL on error
Translates the request given by opcode and the extra arguments into the
wire format and write it to the connection buffer.
For new-id arguments, this function will allocate a new wl_proxy and
send the ID to the server. The new wl_proxy will be returned on success
or NULL on error with errno set accordingly. The newly created proxy
will have the version specified.
The flag WL_MARSHAL_FLAG_DESTROY may be passed to ensure the proxy is
destroyed atomically with the marshalling in order to prevent races that
can occur if the display lock is dropped between the marshal and destroy
operations.
Note
This should not normally be used by non-generated code.
void wl_proxy_set_queue (struct wl_proxy * proxy, struct wl_event_queue *
queue)
Assign a proxy to an event queue
Parameters
proxy The proxy object
queue The event queue that will handle this proxy or NULL
Assign proxy to event queue. Events coming from proxy will be queued in
queue from now. If queue is NULL, then the display's default queue is
set to the proxy.
In order to guarantee proper handing of all events which were queued
before the queue change takes effect, it is required to dispatch the
proxy's old event queue after setting a new event queue.
This is particularly important for multi-threaded setups, where it is
possible for events to be queued to the proxy's old queue from a
different thread during the invocation of this function.
To ensure that all events for a newly created proxy are dispatched on a
particular queue, it is necessary to use a proxy wrapper if events are
read and dispatched on more than one thread. See
wl_proxy_create_wrapper() for more details.
Note
By default, the queue set in proxy is the one inherited from parent.
See also
wl_display_dispatch_queue()
void wl_proxy_set_tag (struct wl_proxy * proxy, const char *const * tag)
Set the tag of a proxy object
A toolkit or application can set a unique tag on a proxy in order to
identify whether an object is managed by itself or some external part.
To create a tag, the recommended way is to define a statically allocated
constant char array containing some descriptive string. The tag will be
the pointer to the non-const pointer to the beginning of the array.
For example, to define and set a tag on a surface managed by a certain
subsystem:
static const char *my_tag = 'my tag';
wl_proxy_set_tag((struct wl_proxy *) surface, &my_tag);
Then, in a callback with wl_surface as an argument, in order to check
whether it's a surface managed by the same subsystem.
const char * const *tag;
tag = wl_proxy_get_tag((struct wl_proxy *) surface);
if (tag != &my_tag)
return;
...
For debugging purposes, a tag should be suitable to be included in a
debug log entry, e.g.
const char * const *tag;
tag = wl_proxy_get_tag((struct wl_proxy *) surface);
printf('Got a surface with the tag %p (%s)\n',
tag, (tag && *tag) ? *tag : '');
Parameters
proxy The proxy object
tag The tag
Since
1.17.90
void wl_proxy_set_user_data (struct wl_proxy * proxy, void * user_data)
Set the user data associated with a proxy
Parameters
proxy The proxy object
user_data The data to be associated with proxy
Set the user data associated with proxy. When events for this proxy are
received, user_data will be supplied to its listener.
void wl_proxy_wrapper_destroy (void * proxy_wrapper)
Destroy a proxy wrapper
Parameters
proxy_wrapper The proxy wrapper to be destroyed
Friends And Related Symbol Documentation
#define WL_MARSHAL_FLAG_DESTROY (1 << 0) [related]
Destroy proxy after marshalling
Author
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Version 1.23.1 Wed Feb 19 2025 20:46:59 wl_proxy(3)
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