event Class
A manual reset event which is explicitly aware of the Concurrency Runtime.
Syntax
class event;
Members
Public Constructors
| Name | Description |
|---|---|
| ~event Destructor | Destroys an event. |
Public Methods
| Name | Description |
|---|---|
| reset | Resets the event to a non-signaled state. |
| set | Signals the event. |
| wait | Waits for the event to become signaled. |
| wait_for_multiple | Waits for multiple events to become signaled. |
Public Constants
| Name | Description |
|---|---|
| timeout_infinite | Value indicating that a wait should never time out. |
Remarks
For more information, see Synchronization Data Structures.
Inheritance Hierarchy
event
Requirements
Header: concrt.h
Namespace: concurrency
event
Constructs a new event.
_CRTIMP event();
Remarks
~event
Destroys an event.
~event();
Remarks
It is expected that there are no threads waiting on the event when the destructor runs. Allowing the event to destruct with threads still waiting on it results in undefined behavior.
reset
Resets the event to a non-signaled state.
void reset();
set
Signals the event.
void set();
Remarks
Signaling the event can cause an arbitrary number of contexts waiting on the event to become runnable.
timeout_infinite
Value indicating that a wait should never time out.
static const unsigned int timeout_infinite = COOPERATIVE_TIMEOUT_INFINITE;
wait
Waits for the event to become signaled.
size_t wait(unsigned int _Timeout = COOPERATIVE_TIMEOUT_INFINITE);
Parameters
_Timeout
Indicates the number of milliseconds before the wait times out. The value COOPERATIVE_TIMEOUT_INFINITE signifies that there is no timeout.
Return Value
If the wait was satisfied, the value 0 is returned; otherwise, the value COOPERATIVE_WAIT_TIMEOUT to indicate that the wait timed out without the event becoming signaled.
Important
In a Universal Windows Platform (UWP) app, do not call wait on the ASTA thread because this call can block the current thread and can cause the app to become unresponsive.
wait_for_multiple
Waits for multiple events to become signaled.
static size_t __cdecl wait_for_multiple(
_In_reads_(count) event** _PPEvents,
size_t count,
bool _FWaitAll,
unsigned int _Timeout = COOPERATIVE_TIMEOUT_INFINITE);
Parameters
_PPEvents
An array of events to wait on. The number of events within the array is indicated by the count parameter.
count
The count of events within the array supplied in the _PPEvents parameter.
_FWaitAll
If set to the value true, the parameter specifies that all events within the array supplied in the _PPEvents parameter must become signaled in order to satisfy the wait. If set to the value false, it specifies that any event within the array supplied in the _PPEvents parameter becoming signaled will satisfy the wait.
_Timeout
Indicates the number of milliseconds before the wait times out. The value COOPERATIVE_TIMEOUT_INFINITE signifies that there is no timeout.
Return Value
If the wait was satisfied, the index within the array supplied in the _PPEvents parameter which satisfied the wait condition; otherwise, the value COOPERATIVE_WAIT_TIMEOUT to indicate that the wait timed out without the condition being satisfied.
Remarks
If the parameter _FWaitAll is set to the value true to indicate that all events must become signaled to satisfy the wait, the index returned by the function carries no special significance other than the fact that it is not the value COOPERATIVE_WAIT_TIMEOUT.
Important
In a Universal Windows Platform (UWP) app, do not call wait_for_multiple on the ASTA thread because this call can block the current thread and can cause the app to become unresponsive.