SemaphoreCreate (Function)

ONLINE HELP
WINDEV, WEBDEV AND WINDEV MOBILE

Version:

Home | Sign in | English

This content has been translated automatically. Click here to view the French version.

Help / WLanguage / WLanguage functions / Standard functions / Process functions / Threads, semaphores, signals and mutex

Mode for sharing the semaphores

WINDEV

WEBDEV

WINDEV Mobile

Others

See also

SemaphoreCreate (Function)

In french: SémaphoreCrée

Creates a semaphore.

Reminder Semaphores can be used to define a protected area of code that can only be executed by a specific number of threads.

Example

// Création d'un sémaphore
SemaphoreCreate("MonSémaphore", 3)

Syntax

SemaphoreCreate(<Semaphore name> [, <Authorization> [, <Use> [, <Options>]]])

<Semaphore name>: Character string

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

<Authorization>: Optional integer

Number of concurrent threads allowed in the protected section. This parameter is set to 1 by default.

<Use>: Optional integer

Number of threads found in the section when creating the semaphore (0 by default).

<Options>: Optional Integer constant

Mode for sharing the semaphore:
shareGlobal The semaphore is shared among all the applications found on the computer.
This constant is not available.
shareNone The semaphore is specific to the application. If SemaphoreDestroy is not called, the semaphore is destroyed at the end of the application.
The semaphores are unique for the application that created them. They cannot be shared between several applications.
shareUser
(default value) The semaphore is shared among all the applications of the session of the user who is running the application.
This constant is not available.

Remarks

Mode for sharing the semaphores

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

The semaphore is created the first time an application in the user's session calls SemaphoreCreate.
The following applications that call SemaphoreCreate connect to the existing semaphore.
The last application that is closed destroys the semaphore.
A semaphore with the same name cannot be used by another user's session on the same machine: the system returns an access rights error.

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

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

Component: wd300vm.dll