ManualEvent (Type of variable)

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Process management functions

Threads, semaphores, signals and mutex

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ManualEvent

Presentation

Example

Declaration

See also

ManualEvent (Type of variable)

In french: SignalManuel

The ManualEvent type is used to manage a manual event. A manual event is used to simplify the synchronization between several threads.

A manual event can only be modified by EventChange.

Remark: We recommend that you use an AutomaticEvent or ManualEvent variable to create an event rather than naming it using a character string. Indeed, using a variable allows you to:

manage the variable scope,
avoid having 2 events with the same name in 2 different threads.

Example

// MAIN THREAD
//------------------
// Define the event
s is ManualEvent
// Start the thread
ThreadExecute("Thread", threadNormal, ProcThread, s)
// Code in parallel with the thread
...
// Wait for the event triggered by the thread
EventWait("s")

// SECONDARY THREAD
// ----------------------
PROCEDURE ProcThread(s)

// Code in the thread
...
// Unlocks the main thread
EventOpen(s)

Declaration

Declaring a manual event (simple syntax) Hide the details

MyVariable is ManualEvent

In this case, the manual event is closed when it is created.

Declaring a manual event (advanced syntax) Hide the details

MyVariable is ManualEvent(<Initial status>)

<Initial status>: Integer constant

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

Remarks

Using the ManualEvent variables

The ManualEvent variables can be used to synchronize threads in the functions:

standard syntax:


EventClose	Closes a synchronization event between several threads.
EventOpen	Opens a synchronization event between several threads.
EventWait	Locks the current thread while waiting for the specified event to be opened.

prefix syntax:


<ManualEvent variable>.Close	Closes a synchronization event between several threads.
<ManualEvent variable>.Open	Opens a synchronization event between several threads.
<ManualEvent variable>.Wait	Locks the current thread while waiting for the specified event to be opened.

During a call to EventOpen (or <ManualEvent variable>.Open), the event remains open:

all the pending threads are freed,
all the threads that will reach the event later will go through without waiting.

During a call to EventClose (or <ManualEvent variable>.Close), the event is closed: all the threads that will reach the event later will remain locked.