CriticalSectionStart (Function)

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Using critical sections
Various
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CriticalSectionStart (Function)

In french: SectionCritiqueDébut

Marks the start of a critical section: no other thread will be able to run the code as long as the current thread does not exit from the critical section.

To exit from the critical section, use CriticalSectionEnd.

Versions 24 and later

When the calls to CriticalSectionStart and CriticalSectionEnd are in the same section of the code, it is recommended to use the type CriticalSection and the syntax USE ... IN.
Example:

// Using a Critical Section variable
S is CriticalSection

// Use for a code block
//---------------------------
USING S IN
// code protected by the critical section
// only one thread will execute this code at a given moment
END

New in version 24

When the calls to CriticalSectionStart and CriticalSectionEnd are in the same section of the code, it is recommended to use the type CriticalSection and the syntax USE ... IN.
Example:

Versions 15 and later

This function is now available for Android applications.

New in version 15

This function is now available for Android applications.

Versions 18 and later

This function is now available in Windows Store apps mode.

This function is now available in Android Widget mode.

New in version 18

This function is now available in Windows Store apps mode.

This function is now available in Android Widget mode.

This function is now available in Windows Store apps mode.

This function is now available in Android Widget mode.

Versions 19 and later

This function is now available for WEBDEV sites in Linux.

This function is now available for WINDEV applications in Linux.

This function is now available for iPhone/iPad applications.

New in version 19

This function is now available for WEBDEV sites in Linux.

This function is now available for WINDEV applications in Linux.

This function is now available for iPhone/iPad applications.

This function is now available for WEBDEV sites in Linux.

This function is now available for WINDEV applications in Linux.

This function is now available for iPhone/iPad applications.

Versions 21 and later

This function is now available in Apple Watch mode.

This function is now available in Universal Windows 10 App mode.

New in version 21

This function is now available in Apple Watch mode.

This function is now available in Universal Windows 10 App mode.

This function is now available in Apple Watch mode.

This function is now available in Universal Windows 10 App mode.

Example

Versions 21 and later

// Critical section on a variable
t is array <critical section> of int
CriticalSectionStart(t)
// Operations on the array by one only thread at a time
CriticalSectionEnd(t)

New in version 21

// Critical section on a variable
t is array <critical section> of int
CriticalSectionStart(t)
// Operations on the array by one only thread at a time
CriticalSectionEnd(t)

// Use of a named critical section
CriticalSectionStart("MySection")
// Two threads will not be able to run this code at the same time
...
CriticalSectionEnd("MySection")

Syntax

Versions 24 and later

Starting a critical section on a code section: using the CriticalSection type Hide the details

CriticalSectionStart(<Critical section>)

<Critical section>: CriticalSection variable

Name of the CriticalSection variable used to identify the critical section.

New in version 24

Starting a critical section on a code section: using the CriticalSection type Hide the details

CriticalSectionStart(<Critical section>)

<Critical section>: CriticalSection variable

Name of the CriticalSection variable used to identify the critical section.

Starting a critical section on a code section: using the CriticalSection type Hide the details

CriticalSectionStart(<Critical section>)

<Critical section>: CriticalSection variable

Name of the CriticalSection variable used to identify the critical section.

Versions 21 and later

Starting a critical section on a variable Hide the details

CriticalSectionStart([<Variable name>])

<Variable name>: Any type

Name of WLanguage variable that must be protected in a critical section. This variable must be defined with the attribute <critical section>.

New in version 21

Starting a critical section on a variable Hide the details

CriticalSectionStart([<Variable name>])

<Variable name>: Any type

Name of WLanguage variable that must be protected in a critical section. This variable must be defined with the attribute <critical section>.

Starting a critical section on a variable Hide the details

CriticalSectionStart([<Variable name>])

<Variable name>: Any type

Name of WLanguage variable that must be protected in a critical section. This variable must be defined with the attribute <critical section>.

Starting a named critical section on a code section Hide the details

CriticalSectionStart([<Section name>])

<Section name>: Optional character string (with quotes)

Identifies the critical section. This parameter is used to identify the protected code sections.
If this parameter is not specified, an automatic critical section is implemented.
Remark: the automatic critical section and the critical section corresponding to an empty string ("") are different.

Remarks

Using critical sections

To handle critical sections, the management mode of threads must be changed by ThreadMode (associated with the ThreadCriticalSection constant).

Various

For more details on critical sections, see Managing the critical sections.
If a thread is destroyed while it is found in a critical section, the critical section is automatically freed.
A single thread is allowed in all the sections with the same name.
If sections use a different name, a thread can run the code of one section while another thread runs the code of another section.
Versions 21 and later
For more details, see Associating a critical section with a variable.
New in version 21
For more details, see Associating a critical section with a variable.
For more details, see Associating a critical section with a variable.

Equivalence

SemaphoreStart("SemaphoreName")

is equivalent to:

CriticalSectionStart("MyCriticalSection")

Indeed, by default, SemaphoreStart creates a semaphore limited to a single thread.

Component: wd260vm.dll