dispatch/source.h

@typedef dispatch_source_t @abstract Dispatch sources are used to automatically submit event handler blocks to dispatch queues in response to external events.

DISPATCH_SOURCE_DECL_SWIFT(dispatch_source, DispatchSource, DispatchSourceProtocol)

@const DISPATCH_SOURCE_TYPE_DATA_ADD @discussion A dispatch source that coalesces data obtained via calls to dispatch_source_merge_data(). An ADD is used to coalesce the data. The handle is unused (pass zero for now). The mask is unused (pass zero for now).

#define DISPATCH_SOURCE_TYPE_DATA_ADD (&_dispatch_source_type_data_add)

@const DISPATCH_SOURCE_TYPE_DATA_OR @discussion A dispatch source that coalesces data obtained via calls to dispatch_source_merge_data(). A bitwise OR is used to coalesce the data. The handle is unused (pass zero for now). The mask is unused (pass zero for now).

#define DISPATCH_SOURCE_TYPE_DATA_OR (&_dispatch_source_type_data_or)

@const DISPATCH_SOURCE_TYPE_DATA_REPLACE @discussion A dispatch source that tracks data obtained via calls to dispatch_source_merge_data(). Newly obtained data values replace existing data values not yet delivered to the source handler A data value of zero will cause the source handler to not be invoked. The handle is unused (pass zero for now). The mask is unused (pass zero for now).

#define DISPATCH_SOURCE_TYPE_DATA_REPLACE (&_dispatch_source_type_data_replace)

@const DISPATCH_SOURCE_TYPE_MACH_SEND @discussion A dispatch source that monitors a Mach port for dead name notifications (send right no longer has any corresponding receive right). The handle is a Mach port with a send or send-once right (mach_port_t). The mask is a mask of desired events from dispatch_source_mach_send_flags_t.

#define DISPATCH_SOURCE_TYPE_MACH_SEND (&_dispatch_source_type_mach_send)

@const DISPATCH_SOURCE_TYPE_MACH_RECV @discussion A dispatch source that monitors a Mach port for pending messages. The handle is a Mach port with a receive right (mach_port_t). The mask is a mask of desired events from dispatch_source_mach_recv_flags_t, but no flags are currently defined (pass zero for now).

#define DISPATCH_SOURCE_TYPE_MACH_RECV (&_dispatch_source_type_mach_recv)

@const DISPATCH_SOURCE_TYPE_MEMORYPRESSURE @discussion A dispatch source that monitors the system for changes in memory pressure condition. The handle is unused (pass zero for now). The mask is a mask of desired events from dispatch_source_memorypressure_flags_t.

#define DISPATCH_SOURCE_TYPE_MEMORYPRESSURE (&_dispatch_source_type_memorypressure)

@const DISPATCH_SOURCE_TYPE_PROC @discussion A dispatch source that monitors an external process for events defined by dispatch_source_proc_flags_t. The handle is a process identifier (pid_t). The mask is a mask of desired events from dispatch_source_proc_flags_t.

#define DISPATCH_SOURCE_TYPE_PROC (&_dispatch_source_type_proc)

@const DISPATCH_SOURCE_TYPE_READ @discussion A dispatch source that monitors a file descriptor for pending bytes available to be read. The handle is a file descriptor (int). The mask is unused (pass zero for now).

#define DISPATCH_SOURCE_TYPE_READ (&_dispatch_source_type_read)

@const DISPATCH_SOURCE_TYPE_SIGNAL @discussion A dispatch source that monitors the current process for signals. The handle is a signal number (int). The mask is unused (pass zero for now).

#define DISPATCH_SOURCE_TYPE_SIGNAL (&_dispatch_source_type_signal)

@const DISPATCH_SOURCE_TYPE_TIMER @discussion A dispatch source that submits the event handler block based on a timer. The handle is unused (pass zero for now). The mask specifies which flags from dispatch_source_timer_flags_t to apply.

#define DISPATCH_SOURCE_TYPE_TIMER (&_dispatch_source_type_timer)

@const DISPATCH_SOURCE_TYPE_VNODE @discussion A dispatch source that monitors a file descriptor for events defined by dispatch_source_vnode_flags_t. The handle is a file descriptor (int). The mask is a mask of desired events from dispatch_source_vnode_flags_t.

#define DISPATCH_SOURCE_TYPE_VNODE (&_dispatch_source_type_vnode)

@const DISPATCH_SOURCE_TYPE_WRITE @discussion A dispatch source that monitors a file descriptor for available buffer space to write bytes. The handle is a file descriptor (int). The mask is unused (pass zero for now).

#define DISPATCH_SOURCE_TYPE_WRITE (&_dispatch_source_type_write)

@typedef dispatch_source_mach_send_flags_t Type of dispatch_source_mach_send flags @constant DISPATCH_MACH_SEND_DEAD The receive right corresponding to the given send right was destroyed.

#define DISPATCH_MACH_SEND_DEAD 0x1

@typedef dispatch_source_mach_recv_flags_t Type of dispatch_source_mach_recv flags

typedef unsigned long dispatch_source_mach_recv_flags_t

@typedef dispatch_source_proc_flags_t Type of dispatch_source_proc flags @constant DISPATCH_PROC_EXIT The process has exited (perhaps cleanly, perhaps not). @constant DISPATCH_PROC_FORK The process has created one or more child processes. @constant DISPATCH_PROC_EXEC The process has become another executable image via exec*() or posix_spawn*(). @constant DISPATCH_PROC_SIGNAL A Unix signal was delivered to the process.

#define DISPATCH_PROC_EXIT 0x80000000

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT dispatch_source_t dispatch_source_create(
	dispatch_source_type_t type,
	uintptr_t handle,
	uintptr_t mask,
	dispatch_queue_t _Nullable queue
)

@function dispatch_source_create @abstract Creates a new dispatch source to monitor low-level system objects and auto- matically submit a handler block to a dispatch queue in response to events. @discussion Dispatch sources are not reentrant. Any events received while the dispatch source is suspended or while the event handler block is currently executing will be coalesced and delivered after the dispatch source is resumed or the event handler block has returned. Dispatch sources are created in an inactive state. After creating the source and setting any desired attributes (i.e. the handler, context, etc.), a call must be made to dispatch_activate() in order to begin event delivery. A source must have been activated before being disposed. Calling dispatch_set_target_queue() on a source once it has been activated is not allowed (see dispatch_activate() and dispatch_set_target_queue()). For backward compatibility reasons, dispatch_resume() on an inactive, and not otherwise suspended source has the same effect as calling dispatch_activate(). For new code, using dispatch_activate() is preferred. @param type Declares the type of the dispatch source. Must be one of the defined dispatch_source_type_t constants. @param handle The underlying system handle to monitor. The interpretation of this argument is determined by the constant provided in the type parameter. @param mask A mask of flags specifying which events are desired. The interpretation of this argument is determined by the constant provided in the type parameter. @param queue The dispatch queue to which the event handler block will be submitted. If queue is DISPATCH_TARGET_QUEUE_DEFAULT, the source will submit the event handler block to the default priority global queue. @result The newly created dispatch source. Or NULL if invalid arguments are passed.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT void dispatch_source_set_event_handler(
	dispatch_source_t source,
	dispatch_block_t _Nullable handler
)

@function dispatch_source_set_event_handler @abstract Sets the event handler block for the given dispatch source. @param source The dispatch source to modify. The result of passing NULL in this parameter is undefined. @param handler The event handler block to submit to the source's target queue.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NOTHROW DISPATCH_SWIFT_UNAVAILABLE("DispatchSource.setEventHandler(self:handler:)") void dispatch_source_set_event_handler_f(
	dispatch_source_t source,
	dispatch_function_t _Nullable handler
)

@function dispatch_source_set_event_handler_f @abstract Sets the event handler function for the given dispatch source. @param source The dispatch source to modify. The result of passing NULL in this parameter is undefined. @param handler The event handler function to submit to the source's target queue. The context parameter passed to the event handler function is the context of the dispatch source current at the time the event handler was set.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT void dispatch_source_set_cancel_handler(
	dispatch_source_t source,
	dispatch_block_t _Nullable handler
)

@function dispatch_source_set_cancel_handler @abstract Sets the cancellation handler block for the given dispatch source. @discussion The cancellation handler (if specified) will be submitted to the source's target queue in response to a call to dispatch_source_cancel() once the system has released all references to the source's underlying handle and the source's event handler block has returned. IMPORTANT: Source cancellation and a cancellation handler are required for file descriptor and mach port based sources in order to safely close the descriptor or destroy the port. Closing the descriptor or port before the cancellation handler is invoked may result in a race condition. If a new descriptor is allocated with the same value as the recently closed descriptor while the source's event handler is still running, the event handler may read/write data to the wrong descriptor. @param source The dispatch source to modify. The result of passing NULL in this parameter is undefined. @param handler The cancellation handler block to submit to the source's target queue.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NOTHROW DISPATCH_SWIFT_UNAVAILABLE("Use DispatchSource.setCancelHandler(self:handler:)") void dispatch_source_set_cancel_handler_f(
	dispatch_source_t source,
	dispatch_function_t _Nullable handler
)

@function dispatch_source_set_cancel_handler_f @abstract Sets the cancellation handler function for the given dispatch source. @discussion See dispatch_source_set_cancel_handler() for more details. @param source The dispatch source to modify. The result of passing NULL in this parameter is undefined. @param handler The cancellation handler function to submit to the source's target queue. The context parameter passed to the event handler function is the current context of the dispatch source at the time the handler call is made.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT void dispatch_source_cancel(
	dispatch_source_t source
)

@function dispatch_source_cancel @abstract Asynchronously cancel the dispatch source, preventing any further invocation of its event handler block. @discussion Cancellation prevents any further invocation of the event handler block for the specified dispatch source, but does not interrupt an event handler block that is already in progress. The cancellation handler is submitted to the source's target queue once the the source's event handler has finished, indicating it is now safe to close the source's handle (i.e. file descriptor or mach port). See dispatch_source_set_cancel_handler() for more information. @param source The dispatch source to be canceled. The result of passing NULL in this parameter is undefined.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_WARN_RESULT DISPATCH_PURE DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT intptr_t dispatch_source_testcancel(
	dispatch_source_t source
)

@function dispatch_source_testcancel @abstract Tests whether the given dispatch source has been canceled. @param source The dispatch source to be tested. The result of passing NULL in this parameter is undefined. @result Non-zero if canceled and zero if not canceled.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_WARN_RESULT DISPATCH_PURE DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT uintptr_t dispatch_source_get_handle(
	dispatch_source_t source
)

@function dispatch_source_get_handle @abstract Returns the underlying system handle associated with this dispatch source. @param source The result of passing NULL in this parameter is undefined. @result The return value should be interpreted according to the type of the dispatch source, and may be one of the following handles: DISPATCH_SOURCE_TYPE_DATA_ADD: n/a DISPATCH_SOURCE_TYPE_DATA_OR: n/a DISPATCH_SOURCE_TYPE_DATA_REPLACE: n/a DISPATCH_SOURCE_TYPE_MACH_SEND: mach port (mach_port_t) DISPATCH_SOURCE_TYPE_MACH_RECV: mach port (mach_port_t) DISPATCH_SOURCE_TYPE_MEMORYPRESSURE n/a DISPATCH_SOURCE_TYPE_PROC: process identifier (pid_t) DISPATCH_SOURCE_TYPE_READ: file descriptor (int) DISPATCH_SOURCE_TYPE_SIGNAL: signal number (int) DISPATCH_SOURCE_TYPE_TIMER: n/a DISPATCH_SOURCE_TYPE_VNODE: file descriptor (int) DISPATCH_SOURCE_TYPE_WRITE: file descriptor (int)

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_WARN_RESULT DISPATCH_PURE DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT uintptr_t dispatch_source_get_mask(
	dispatch_source_t source
)

@function dispatch_source_get_mask @abstract Returns the mask of events monitored by the dispatch source. @param source The result of passing NULL in this parameter is undefined. @result The return value should be interpreted according to the type of the dispatch source, and may be one of the following flag sets: DISPATCH_SOURCE_TYPE_DATA_ADD: n/a DISPATCH_SOURCE_TYPE_DATA_OR: n/a DISPATCH_SOURCE_TYPE_DATA_REPLACE: n/a DISPATCH_SOURCE_TYPE_MACH_SEND: dispatch_source_mach_send_flags_t DISPATCH_SOURCE_TYPE_MACH_RECV: dispatch_source_mach_recv_flags_t DISPATCH_SOURCE_TYPE_MEMORYPRESSURE dispatch_source_memorypressure_flags_t DISPATCH_SOURCE_TYPE_PROC: dispatch_source_proc_flags_t DISPATCH_SOURCE_TYPE_READ: n/a DISPATCH_SOURCE_TYPE_SIGNAL: n/a DISPATCH_SOURCE_TYPE_TIMER: dispatch_source_timer_flags_t DISPATCH_SOURCE_TYPE_VNODE: dispatch_source_vnode_flags_t DISPATCH_SOURCE_TYPE_WRITE: n/a

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_WARN_RESULT DISPATCH_PURE DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT uintptr_t dispatch_source_get_data(
	dispatch_source_t source
)

@function dispatch_source_get_data @abstract Returns pending data for the dispatch source. @discussion This function is intended to be called from within the event handler block. The result of calling this function outside of the event handler callback is undefined. @param source The result of passing NULL in this parameter is undefined. @result The return value should be interpreted according to the type of the dispatch source, and may be one of the following: DISPATCH_SOURCE_TYPE_DATA_ADD: application defined data DISPATCH_SOURCE_TYPE_DATA_OR: application defined data DISPATCH_SOURCE_TYPE_DATA_REPLACE: application defined data DISPATCH_SOURCE_TYPE_MACH_SEND: dispatch_source_mach_send_flags_t DISPATCH_SOURCE_TYPE_MACH_RECV: dispatch_source_mach_recv_flags_t DISPATCH_SOURCE_TYPE_MEMORYPRESSURE dispatch_source_memorypressure_flags_t DISPATCH_SOURCE_TYPE_PROC: dispatch_source_proc_flags_t DISPATCH_SOURCE_TYPE_READ: estimated bytes available to read DISPATCH_SOURCE_TYPE_SIGNAL: number of signals delivered since the last handler invocation DISPATCH_SOURCE_TYPE_TIMER: number of times the timer has fired since the last handler invocation DISPATCH_SOURCE_TYPE_VNODE: dispatch_source_vnode_flags_t DISPATCH_SOURCE_TYPE_WRITE: estimated buffer space available

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT void dispatch_source_merge_data(
	dispatch_source_t source,
	uintptr_t value
)

@function dispatch_source_merge_data @abstract Merges data into a dispatch source of type DISPATCH_SOURCE_TYPE_DATA_ADD, DISPATCH_SOURCE_TYPE_DATA_OR or DISPATCH_SOURCE_TYPE_DATA_REPLACE, and submits its event handler block to its target queue. @param source The result of passing NULL in this parameter is undefined. @param value The value to coalesce with the pending data using a logical OR or an ADD as specified by the dispatch source type. A value of zero has no effect and will not result in the submission of the event handler block.

API_AVAILABLE(macos(10.6), ios(4.0)) DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT void dispatch_source_set_timer(
	dispatch_source_t source,
	dispatch_time_t start,
	uint64_t interval,
	uint64_t leeway
)

@function dispatch_source_set_timer @abstract Sets a start time, interval, and leeway value for a timer source. @discussion Once this function returns, any pending source data accumulated for the previous timer values has been cleared; the next fire of the timer will occur at 'start', and every 'interval' nanoseconds thereafter until the timer source is canceled. Any fire of the timer may be delayed by the system in order to improve power consumption and system performance. The upper limit to the allowable delay may be configured with the 'leeway' argument, the lower limit is under the control of the system. For the initial timer fire at 'start', the upper limit to the allowable delay is set to 'leeway' nanoseconds. For the subsequent timer fires at 'start' + N * 'interval', the upper limit is MIN('leeway','interval'/2). The lower limit to the allowable delay may vary with process state such as visibility of application UI. If the specified timer source was created with a mask of DISPATCH_TIMER_STRICT, the system will make a best effort to strictly observe the provided 'leeway' value even if it is smaller than the current lower limit. Note that a minimal amount of delay is to be expected even if this flag is specified. The 'start' argument also determines which clock will be used for the timer: If 'start' is DISPATCH_TIME_NOW or was created with dispatch_time(3), the timer is based on up time (which is obtained from mach_absolute_time() on Apple platforms). If 'start' was created with dispatch_walltime(3), the timer is based on gettimeofday(3). Calling this function has no effect if the timer source has already been canceled. @param start The start time of the timer. See dispatch_time() and dispatch_walltime() for more information. @param interval The nanosecond interval for the timer. Use DISPATCH_TIME_FOREVER for a one-shot timer. @param leeway The nanosecond leeway for the timer.

API_AVAILABLE(macos(10.7), ios(4.3)) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NOTHROW DISPATCH_REFINED_FOR_SWIFT void dispatch_source_set_registration_handler(
	dispatch_source_t source,
	dispatch_block_t _Nullable handler
)

@function dispatch_source_set_registration_handler @abstract Sets the registration handler block for the given dispatch source. @discussion The registration handler (if specified) will be submitted to the source's target queue once the corresponding kevent() has been registered with the system, following the initial dispatch_resume() of the source. If a source is already registered when the registration handler is set, the registration handler will be invoked immediately. @param source The dispatch source to modify. The result of passing NULL in this parameter is undefined. @param handler The registration handler block to submit to the source's target queue.

API_AVAILABLE(macos(10.7), ios(4.3)) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NOTHROW DISPATCH_SWIFT_UNAVAILABLE("Use DispatchSource.setRegistrationHandler(self:handler:)") void dispatch_source_set_registration_handler_f(
	dispatch_source_t source,
	dispatch_function_t _Nullable handler
)

@function dispatch_source_set_registration_handler_f @abstract Sets the registration handler function for the given dispatch source. @discussion See dispatch_source_set_registration_handler() for more details. @param source The dispatch source to modify. The result of passing NULL in this parameter is undefined. @param handler The registration handler function to submit to the source's target queue. The context parameter passed to the registration handler function is the current context of the dispatch source at the time the handler call is made.