EventCreate (Function)

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Standard functions

Process management functions

Threads, semaphores, signals and mutex

WLanguage functions

EventCreate

Presentation

Example

Mode for sharing the events

See also

EventCreate (Function)

In french: SignalCrée

Creates an event. An event is used to synchronize several threads at the same time. If the event is open, all the threads waiting for the event are unlocked.

Example

// Create an event
EventCreate("Let's go", eventManual, eventClose)
// Run a first thread
ThreadExecute("Thread1", threadNormal, "Thread_First")
// Locks the current thread until the event is obtained
ThreadWaitSignal()

// Run a second thread
ThreadExecute("Thread2", threadNormal, "Thread_Second")
// Locks the current thread until the event is obtained
ThreadWaitSignal()

// Modifies the event to run the threads
EventChange("Let's go", eventOpen)

//----------------------------------------------
PROCEDURE Thread_First()
Trace(dbgInfo(dbgProcess) + " - ThreadSendSignal(threadMain)")
ThreadSendSignal(threadMain)
EventWait("Let's go")
Trace(dbgInfo(dbgProcess) + " - Event received")

//--------------------------------------------
PROCEDURE Thread_Second()
Trace(dbgInfo(dbgProcess) + " - ThreadSendSignal(threadMain)")
ThreadSendSignal(threadMain)
EventWait("Let's go")
Trace(dbgInfo(dbgProcess) + " - Event received")

Syntax

EventCreate(<Event> [, <Mode> [, <Initial status> [, <Options>]]])

<Event>: Character string

Name of the event to create. This name will be used by all the event management functions.

<Mode>: Optional constant

Mode for managing the event:
eventAutomatic
(Default value) After its opening, the event is automatically closed as soon as a single thread is unlocked.
eventManual The event is modified by EventChange.

<Initial status>: Optional constant

Initial status of the event:
eventClose
(Default value) The event is closed when it is created.
eventOpen The event is open when it is created.

<Options>: Optional Integer constant

Mode for sharing the event:
shareGlobal The event is shared between all the applications found on the computer.
This constant is not available.
shareNone The event is specific to the application. If EventDestroy is not called, the event is destroyed at the end of the application.
The events are unique to the application that created them. They cannot be shared between several applications.
shareUser
(Default value) The event is shared between all the applications of the session of the user who runs the application.
This constant is not available.
Mode for destroying the event:
DestructionWithoutModification By default, an event is automatically modified during its destruction. If the event is created with the DestructionWithoutModification constant, it will not be modified during the call to EventDestroy or during the automatic destruction of the event when closing the application.
This constant is not available.
The information regarding the share mode and the destruction mode of the event can be combined.

Remarks

Mode for sharing the events

In shareUser mode, the event is shared between all the applications of the session of the user who runs the application.

The event is created by the first application of the session of the user who calls EventCreate.
The following applications that call EventCreate connect to the existing semaphore.
The last application that is closed destroys the event.
An event with the same name cannot be used by a session of another user on the same computer: the system returns an error of access rights.

In shareGlobal mode, the event is shared among all the applications found on the computer.

The event is created by the first application that calls EventCreate.
The following applications that call EventCreate connect to the existing semaphore.
The last application that is closed destroys the event.

Component: wd270vm.dll