Asynchrony

Asynchronous utility functions. More...

Macros
#define	using_cancel_scope()
	Execute under a cancelation scope. More...

Typedefs
typedef void()	nodec_actionfun_t()
	Type of actions with no arguments and no return value.

Functions
void	async_scoped_cancel ()
	Asynchronously cancel all outstanding requests under the same cancelation scope. More...
bool	async_scoped_is_canceled ()
	Is the current scope canceled?
void	async_interleave (size_t n, lh_actionfun *actions[], lh_value arg_results[])
	Interleave a fixed number of strands. More...
lh_value	async_strand_create (lh_actionfun *action, lh_value arg, lh_exception **exn)
	Dynamically create an interleaved strand. More...
size_t	nodec_current_strand_count ()
	Return the number of currently interleaved strands under the innermost interleaved handler.
lh_value	async_interleave_dynamic (lh_actionfun action, lh_value arg)
	Interleave a dynamic number of strands. More...
lh_value	async_timeout (lh_actionfun *action, lh_value arg, uint64_t timeout, bool *timedout)
	General timeout routine over an action. More...
bool	async_firstof (nodec_actionfun_t *action1, nodec_actionfun_t *action2)
	Return when the either action is done, canceling the other. More...
lh_value	async_firstof_ex (lh_actionfun *action1, lh_value arg1, lh_actionfun *action2, lh_value arg2, bool *first, bool ignore_exn)
	Return the value of the first returning action, canceling the other.
void	async_wait (uint64_t timeout)
	Asynchronously wait for timeout milli-seconds.
void	async_yield ()
	Yield asynchronously to other strands. More...

Detailed Description

Asynchronous utility functions.

Macro Definition Documentation

using_cancel_scope

#define using_cancel_scope

(

)

Execute under a cancelation scope.

See also

async_scoped_cancel()

Function Documentation

async_firstof()

bool async_firstof	(	nodec_actionfun_t *	action1,
		nodec_actionfun_t *	action2
	)

Return when the either action is done, canceling the other.

Returns

true if the first action was finished first.

async_interleave()

void async_interleave	(	size_t	n,
		lh_actionfun *	actions[],
		lh_value	arg_results[]
	)

Interleave a fixed number of strands.

Interleave with arguments arg_results. The result of each action is stored again in arg_results; when an exception is raised, it is rethrown from interleave once all its actions have finished. Interleave introduces a cancelation scope.

Parameters

n	Number of strands to create.
actions	Array of size n containing the action to execute for each strand.
arg_results	Array of size n containing the argument values passed to each action and also to store the result of each action.

async_interleave_dynamic()

lh_value async_interleave_dynamic	(	lh_actionfun	action,
		lh_value	arg
	)

Interleave a dynamic number of strands.

Parameters

action	The initial action. This can use async_dynamic_spawn() to dynamically interleave more actions.
arg	Argument passed to action.

Returns

The result from action. Only returns once action and all dynamically spawned actions are done.

async_scoped_cancel()

void async_scoped_cancel

(

)

Asynchronously cancel all outstanding requests under the same cancelation scope.

This is a powerful primitive that enables cancelation of operations and for example enables timeouts over any composition of asynchronous operations. When async_scoped_cancel() is called, it cancels all outstanding (interleaved) operations under the same innermost cancelation scope (raising a cancel exception for all of them).

async_strand_create()

lh_value async_strand_create	(	lh_actionfun *	action,
		lh_value	arg,
		lh_exception **	exn
	)

Dynamically create an interleaved strand.

Only works in the action given to async_interleave_dynamic()!

async_timeout()

lh_value async_timeout	(	lh_actionfun *	action,
		lh_value	arg,
		uint64_t	timeout,
		bool *	timedout
	)

General timeout routine over an action.

Parameters

action	The action to run.
arg	Argument passed to action.
timeout	The time in milli-seconds after which action is canceled.
timedout	If not NULL, gets set whether the action timed out or not.

Returns

The result of action or lh_value_null if it timed out.

async_yield()

void async_yield

(

)

Yield asynchronously to other strands.

Equivalent to async_wait() with a 0 timeout.