Wakers

Overview

Queue work in response to async events.

Learn more: Wakers

Classes
class	pw::async2::Waker

Macros
#define	PW_ASYNC_STORE_WAKER(context, waker_out, wait_reason_string)
#define	PW_ASYNC_TRY_STORE_WAKER(context, waker_out, wait_reason_string)
#define	PW_ASYNC_CLONE_WAKER(waker_in, waker_out, wait_reason_string)
#define	PW_ASYNC_TRY_CLONE_WAKER(waker_in, waker_out, wait_reason_string)

Macro Definition Documentation

PW_ASYNC_CLONE_WAKER

#define PW_ASYNC_CLONE_WAKER	(		waker_in,
			waker_out,
			wait_reason_string
	)

Value:

  do {                                                                     \
    bool waker_had_space =                                                 \
        PW_ASYNC_TRY_CLONE_WAKER(waker_in, waker_out, wait_reason_string); \
    PW_ASSERT(waker_had_space);                                            \
  } while (0)

Attempts to store a waker associated with waker_in into waker_out. Crashes if the waker cannot be stored into waker_out due to the target waker already referencing a task.

When the stored waker is later awoken with pw::async2::Waker::Wake, the pw::async2::Task will be awoken and its DoPend method will be invoked again.

wait_reason_string is a human-readable description of why the task is blocked. If the module configuration option PW_ASYNC2_DEBUG_WAIT_REASON is set, this string will be stored with the waker and reported by Dispatcher::LogRegisteredTasks when its associated task is blocked.

PW_ASYNC_STORE_WAKER

#define PW_ASYNC_STORE_WAKER	(		context,
			waker_out,
			wait_reason_string
	)

Value:

  do {                                                                    \
    bool waker_had_space =                                                \
        PW_ASYNC_TRY_STORE_WAKER(context, waker_out, wait_reason_string); \
    PW_ASSERT(waker_had_space);                                           \
  } while (0)

Attempts to store a waker associated with the current context into waker_out. Crashes if the waker cannot be stored into waker_out due to the target waker already referencing a task.

When the stored waker is later awoken with pw::async2::Waker::Wake, the pw::async2::Task will be awoken and its DoPend method will be invoked again.

wait_reason_string is a human-readable description of why the task is blocked. If the module configuration option PW_ASYNC2_DEBUG_WAIT_REASON is set, this string will be stored with the waker and reported by Dispatcher::LogRegisteredTasks when its associated task is blocked.

PW_ASYNC_TRY_CLONE_WAKER

#define PW_ASYNC_TRY_CLONE_WAKER	(		waker_in,
			waker_out,
			wait_reason_string
	)

Value:

  _PW_ASYNC_TRY_GET_WAKER(::pw::async2::internal::CloneWaker,             \
                          waker_in,                                       \
                          waker_out,                                      \
                          wait_reason_string)

Attempts to store a waker associated with waker_in into waker_out. If the waker cannot be stored into waker_out due to the target waker already referencing a task, returns false and does not modify it.

When the stored waker is later awoken with pw::async2::Waker::Wake, the pw::async2::Task will be awoken and its DoPend method will be invoked again.

wait_reason_string is a human-readable description of why the task is blocked. If the module configuration option PW_ASYNC2_DEBUG_WAIT_REASON is set, this string will be stored with the waker and reported by Dispatcher::LogRegisteredTasks when its associated task is blocked.

PW_ASYNC_TRY_STORE_WAKER

#define PW_ASYNC_TRY_STORE_WAKER	(		context,
			waker_out,
			wait_reason_string
	)

Value:

  _PW_ASYNC_TRY_GET_WAKER(::pw::async2::internal::StoreWaker,            \
                          context,                                       \
                          waker_out,                                     \
                          wait_reason_string)

Attempts to store a waker associated with the current context into waker_out. If the waker cannot be stored into waker_out due to the target waker already referencing a task, returns false and does not modify it.

When the stored waker is later awoken with pw::async2::Waker::Wake, the pw::async2::Task will be awoken and its DoPend method will be invoked again.

wait_reason_string is a human-readable description of why the task is blocked. If the module configuration option PW_ASYNC2_DEBUG_WAIT_REASON is set, this string will be stored with the waker and reported by Dispatcher::LogRegisteredTasks when its associated task is blocked.