Loop

Event loop interface More...

Files
file	loop.h
	spa/support/loop.h

Data Structures
struct	spa_loop
struct	spa_loop_control
struct	spa_loop_utils
struct	spa_source
struct	spa_loop_methods
	Register sources and work items to an event loop. More...
struct	spa_loop_control_hooks
	Control hooks. More...
struct	spa_loop_control_methods
	Control an event loop. More...
struct	spa_loop_utils_methods
	Create sources for an event loop. More...

Typedefs
typedef void(*	spa_source_func_t) (struct spa_source *source)
typedef int(*	spa_invoke_func_t) (struct spa_loop *loop, bool async, uint32_t seq, const void *data, size_t size, void *user_data)
typedef void(*	spa_source_io_func_t) (void *data, int fd, uint32_t mask)
typedef void(*	spa_source_idle_func_t) (void *data)
typedef void(*	spa_source_event_func_t) (void *data, uint64_t count)
typedef void(*	spa_source_timer_func_t) (void *data, uint64_t expirations)
typedef void(*	spa_source_signal_func_t) (void *data, int signal_number)

Macros
#define	SPA_TYPE_INTERFACE_Loop   SPA_TYPE_INFO_INTERFACE_BASE "Loop"
#define	SPA_TYPE_INTERFACE_DataLoop   SPA_TYPE_INFO_INTERFACE_BASE "DataLoop"
#define	SPA_VERSION_LOOP   0
#define	SPA_TYPE_INTERFACE_LoopControl   SPA_TYPE_INFO_INTERFACE_BASE "LoopControl"
#define	SPA_VERSION_LOOP_CONTROL   1
#define	SPA_TYPE_INTERFACE_LoopUtils   SPA_TYPE_INFO_INTERFACE_BASE "LoopUtils"
#define	SPA_VERSION_LOOP_UTILS   0
#define	SPA_VERSION_LOOP_METHODS   0
#define	spa_loop_method(o, method, version, ...)
#define	spa_loop_add_source(l, ...)   spa_loop_method(l,add_source,0,##__VA_ARGS__)
	Add a source to the loop.
#define	spa_loop_update_source(l, ...)   spa_loop_method(l,update_source,0,##__VA_ARGS__)
	Update the source io mask.
#define	spa_loop_remove_source(l, ...)   spa_loop_method(l,remove_source,0,##__VA_ARGS__)
	Remove a source from the loop.
#define	spa_loop_invoke(l, ...)   spa_loop_method(l,invoke,0,##__VA_ARGS__)
	Invoke a function in the context of this loop.
#define	SPA_VERSION_LOOP_CONTROL_HOOKS   0
#define	spa_loop_control_hook_before(l)
#define	spa_loop_control_hook_after(l)
#define	SPA_VERSION_LOOP_CONTROL_METHODS   1
#define	spa_loop_control_method_v(o, method, version, ...)
#define	spa_loop_control_method_r(o, method, version, ...)
#define	spa_loop_control_method_fast_r(o, method, version, ...)
#define	spa_loop_control_get_fd(l)   spa_loop_control_method_r(l,get_fd,0)
#define	spa_loop_control_add_hook(l, ...)   spa_loop_control_method_v(l,add_hook,0,__VA_ARGS__)
	Add a hook.
#define	spa_loop_control_enter(l)   spa_loop_control_method_v(l,enter,0)
	Enter a loop.
#define	spa_loop_control_leave(l)   spa_loop_control_method_v(l,leave,0)
	Leave a loop.
#define	spa_loop_control_iterate(l, ...)   spa_loop_control_method_r(l,iterate,0,__VA_ARGS__)
	Perform one iteration of the loop.
#define	spa_loop_control_check(l)   spa_loop_control_method_r(l,check,1)
	Check context of the loop.
#define	spa_loop_control_iterate_fast(l, ...)   spa_loop_control_method_fast_r(l,iterate,0,__VA_ARGS__)
#define	SPA_VERSION_LOOP_UTILS_METHODS   0
#define	spa_loop_utils_method_v(o, method, version, ...)
#define	spa_loop_utils_method_r(o, method, version, ...)
#define	spa_loop_utils_method_s(o, method, version, ...)
#define	spa_loop_utils_add_io(l, ...)   spa_loop_utils_method_s(l,add_io,0,__VA_ARGS__)
#define	spa_loop_utils_update_io(l, ...)   spa_loop_utils_method_r(l,update_io,0,__VA_ARGS__)
#define	spa_loop_utils_add_idle(l, ...)   spa_loop_utils_method_s(l,add_idle,0,__VA_ARGS__)
#define	spa_loop_utils_enable_idle(l, ...)   spa_loop_utils_method_r(l,enable_idle,0,__VA_ARGS__)
#define	spa_loop_utils_add_event(l, ...)   spa_loop_utils_method_s(l,add_event,0,__VA_ARGS__)
#define	spa_loop_utils_signal_event(l, ...)   spa_loop_utils_method_r(l,signal_event,0,__VA_ARGS__)
#define	spa_loop_utils_add_timer(l, ...)   spa_loop_utils_method_s(l,add_timer,0,__VA_ARGS__)
#define	spa_loop_utils_update_timer(l, ...)   spa_loop_utils_method_r(l,update_timer,0,__VA_ARGS__)
#define	spa_loop_utils_add_signal(l, ...)   spa_loop_utils_method_s(l,add_signal,0,__VA_ARGS__)
#define	spa_loop_utils_destroy_source(l, ...)   spa_loop_utils_method_v(l,destroy_source,0,__VA_ARGS__)
	destroy a source allocated with this interface.

Detailed Description

Event loop interface

Typedef Documentation

spa_source_func_t

typedef void(* spa_source_func_t) (struct spa_source *source)

spa_invoke_func_t

typedef int(* spa_invoke_func_t) (struct spa_loop *loop, bool async, uint32_t seq, const void *data, size_t size, void *user_data)

spa_source_io_func_t

typedef void(* spa_source_io_func_t) (void *data, int fd, uint32_t mask)

spa_source_idle_func_t

typedef void(* spa_source_idle_func_t) (void *data)

spa_source_event_func_t

typedef void(* spa_source_event_func_t) (void *data, uint64_t count)

spa_source_timer_func_t

typedef void(* spa_source_timer_func_t) (void *data, uint64_t expirations)

spa_source_signal_func_t

typedef void(* spa_source_signal_func_t) (void *data, int signal_number)

Macro Definition Documentation

SPA_TYPE_INTERFACE_Loop

#define SPA_TYPE_INTERFACE_Loop   SPA_TYPE_INFO_INTERFACE_BASE "Loop"

Examples

local-v4l2.c, spa/examples/adapter-control.c, spa/examples/example-control.c, spa/examples/local-libcamera.c, and spa/examples/local-v4l2.c.

SPA_TYPE_INTERFACE_DataLoop

#define SPA_TYPE_INTERFACE_DataLoop   SPA_TYPE_INFO_INTERFACE_BASE "DataLoop"

Examples

local-v4l2.c, spa/examples/adapter-control.c, spa/examples/example-control.c, spa/examples/local-libcamera.c, and spa/examples/local-v4l2.c.

SPA_VERSION_LOOP

#define SPA_VERSION_LOOP   0

SPA_TYPE_INTERFACE_LoopControl

#define SPA_TYPE_INTERFACE_LoopControl   SPA_TYPE_INFO_INTERFACE_BASE "LoopControl"

Examples

local-v4l2.c, spa/examples/adapter-control.c, spa/examples/example-control.c, spa/examples/local-libcamera.c, and spa/examples/local-v4l2.c.

SPA_VERSION_LOOP_CONTROL

#define SPA_VERSION_LOOP_CONTROL   1

SPA_TYPE_INTERFACE_LoopUtils

#define SPA_TYPE_INTERFACE_LoopUtils   SPA_TYPE_INFO_INTERFACE_BASE "LoopUtils"

SPA_VERSION_LOOP_UTILS

#define SPA_VERSION_LOOP_UTILS   0

SPA_VERSION_LOOP_METHODS

#define SPA_VERSION_LOOP_METHODS   0

spa_loop_method

#define spa_loop_method	(		o,
			method,
			version,
			... )

spa_loop_add_source

#define spa_loop_add_source	(		l,
			... )   spa_loop_method(l,add_source,0,##__VA_ARGS__)

Add a source to the loop.

Must be called from the loop's own thread.

Parameters

[in]	object	The callbacks data.
[in]	source	The source.

Returns

0 on success, negative errno-style value on failure.

See also

spa_loop_methods.add_source

spa_loop_update_source

#define spa_loop_update_source	(		l,
			... )   spa_loop_method(l,update_source,0,##__VA_ARGS__)

Update the source io mask.

Must be called from the loop's own thread.

Parameters

[in]	object	The callbacks data.
[in]	source	The source.

Returns

0 on success, negative errno-style value on failure.

See also

spa_loop_methods.update_source

spa_loop_remove_source

#define spa_loop_remove_source	(		l,
			... )   spa_loop_method(l,remove_source,0,##__VA_ARGS__)

Remove a source from the loop.

Must be called from the loop's own thread.

Parameters

[in]	object	The callbacks data.
[in]	source	The source.

Returns

0 on success, negative errno-style value on failure.

See also

spa_loop_methods.remove_source

spa_loop_invoke

#define spa_loop_invoke	(		l,
			... )   spa_loop_method(l,invoke,0,##__VA_ARGS__)

Invoke a function in the context of this loop.

May be called from any thread and multiple threads at the same time. If called from the loop's thread, all callbacks previously queued with invoke() will be run synchronously, which might cause unexpected reentrancy problems.

Parameters

[in]	object	The callbacks data.
	func	The function to be invoked.
	seq	An opaque sequence number. This will be made available to func.
[in]	data	Data that will be copied into the internal ring buffer and made available to func. Because this data is copied, it is okay to pass a pointer to a local variable, but do not pass a pointer to an object that has identity.
	size	The size of data to copy.
	block	If \true, do not return until func has been called. Otherwise, returns immediately. Passing \true does not risk a deadlock because the data thread is never allowed to wait on any other thread.
	user_data	An opaque pointer passed to func.

Returns

-EPIPE if the internal ring buffer filled up, if block is \false, 0 if seq was SPA_ID_INVALID or seq with the ASYNC flag set or the return value of func otherwise.

See also

spa_loop_methods.invoke

SPA_VERSION_LOOP_CONTROL_HOOKS

#define SPA_VERSION_LOOP_CONTROL_HOOKS   0

spa_loop_control_hook_before

#define spa_loop_control_hook_before

(

l

)

spa_loop_control_hook_after

#define spa_loop_control_hook_after

(

l

)

SPA_VERSION_LOOP_CONTROL_METHODS

#define SPA_VERSION_LOOP_CONTROL_METHODS   1

spa_loop_control_method_v

#define spa_loop_control_method_v	(		o,
			method,
			version,
			... )

spa_loop_control_method_r

#define spa_loop_control_method_r	(		o,
			method,
			version,
			... )

spa_loop_control_method_fast_r

#define spa_loop_control_method_fast_r	(		o,
			method,
			version,
			... )

spa_loop_control_get_fd

#define spa_loop_control_get_fd

(

l

)

spa_loop_control_method_r(l,get_fd,0)

See also

spa_loop_control_methods.get_fd

spa_loop_control_add_hook

#define spa_loop_control_add_hook	(		l,
			... )   spa_loop_control_method_v(l,add_hook,0,__VA_ARGS__)

Add a hook.

Parameters

ctrl	the control to change
hooks	the hooks to add

Adds hooks to the loop controlled by ctrl.

See also

spa_loop_control_methods.add_hook

spa_loop_control_enter

#define spa_loop_control_enter

(

l

)

spa_loop_control_method_v(l,enter,0)

Enter a loop.

Parameters

ctrl	the control

Start an iteration of the loop. This function should be called before calling iterate and is typically used to capture the thread that this loop will run in.

See also

spa_loop_control_methods.enter

Examples

local-v4l2.c, spa/examples/adapter-control.c, spa/examples/example-control.c, spa/examples/local-libcamera.c, and spa/examples/local-v4l2.c.

spa_loop_control_leave

#define spa_loop_control_leave

(

l

)

spa_loop_control_method_v(l,leave,0)

Leave a loop.

Parameters

ctrl	the control

Ends the iteration of a loop. This should be called after calling iterate.

See also

spa_loop_control_methods.leave

Examples

local-v4l2.c, spa/examples/adapter-control.c, spa/examples/example-control.c, spa/examples/local-libcamera.c, and spa/examples/local-v4l2.c.

spa_loop_control_iterate

#define spa_loop_control_iterate	(		l,
			... )   spa_loop_control_method_r(l,iterate,0,__VA_ARGS__)

Perform one iteration of the loop.

Parameters

ctrl	the control
timeout	an optional timeout in milliseconds. 0 for no timeout, -1 for infinite timeout.

This function will block up to timeout milliseconds and then dispatch the fds with activity. The number of dispatched fds is returned.

See also

spa_loop_control_methods.iterate

Examples

local-v4l2.c, spa/examples/adapter-control.c, spa/examples/example-control.c, spa/examples/local-libcamera.c, and spa/examples/local-v4l2.c.

spa_loop_control_check

#define spa_loop_control_check

(

l

)

spa_loop_control_method_r(l,check,1)

Check context of the loop.

Parameters

ctrl	the control

This function will check if the current thread is currently the one that did the enter call. Since version 1:1.

returns 1 on success, 0 or negative errno value on error.

See also

spa_loop_control_methods.check

spa_loop_control_iterate_fast

#define spa_loop_control_iterate_fast	(		l,
			... )   spa_loop_control_method_fast_r(l,iterate,0,__VA_ARGS__)

SPA_VERSION_LOOP_UTILS_METHODS

#define SPA_VERSION_LOOP_UTILS_METHODS   0

spa_loop_utils_method_v

#define spa_loop_utils_method_v	(		o,
			method,
			version,
			... )

spa_loop_utils_method_r

#define spa_loop_utils_method_r	(		o,
			method,
			version,
			... )

spa_loop_utils_method_s

#define spa_loop_utils_method_s	(		o,
			method,
			version,
			... )

spa_loop_utils_add_io

#define spa_loop_utils_add_io	(		l,
			... )   spa_loop_utils_method_s(l,add_io,0,__VA_ARGS__)

See also

spa_loop_utils_methods.add_io

spa_loop_utils_update_io

#define spa_loop_utils_update_io	(		l,
			... )   spa_loop_utils_method_r(l,update_io,0,__VA_ARGS__)

See also

spa_loop_utils_methods.update_io

spa_loop_utils_add_idle

#define spa_loop_utils_add_idle	(		l,
			... )   spa_loop_utils_method_s(l,add_idle,0,__VA_ARGS__)

See also

spa_loop_utils_methods.add_idle

spa_loop_utils_enable_idle

#define spa_loop_utils_enable_idle	(		l,
			... )   spa_loop_utils_method_r(l,enable_idle,0,__VA_ARGS__)

See also

spa_loop_utils_methods.enable_idle

spa_loop_utils_add_event

#define spa_loop_utils_add_event	(		l,
			... )   spa_loop_utils_method_s(l,add_event,0,__VA_ARGS__)

See also

spa_loop_utils_methods.add_event

spa_loop_utils_signal_event

#define spa_loop_utils_signal_event	(		l,
			... )   spa_loop_utils_method_r(l,signal_event,0,__VA_ARGS__)

See also

spa_loop_utils_methods.signal_event

spa_loop_utils_add_timer

#define spa_loop_utils_add_timer	(		l,
			... )   spa_loop_utils_method_s(l,add_timer,0,__VA_ARGS__)

See also

spa_loop_utils_methods.add_timer

spa_loop_utils_update_timer

#define spa_loop_utils_update_timer	(		l,
			... )   spa_loop_utils_method_r(l,update_timer,0,__VA_ARGS__)

See also

spa_loop_utils_methods.update_timer

spa_loop_utils_add_signal

#define spa_loop_utils_add_signal	(		l,
			... )   spa_loop_utils_method_s(l,add_signal,0,__VA_ARGS__)

See also

spa_loop_utils_methods.add_signal

spa_loop_utils_destroy_source

#define spa_loop_utils_destroy_source	(		l,
			... )   spa_loop_utils_method_v(l,destroy_source,0,__VA_ARGS__)

destroy a source allocated with this interface.

This function should only be called when the loop is not running or from the context of the running loop

See also

spa_loop_utils_methods.destroy_source