Extern (Reserved word)

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Including constants
Deploying the application

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List of reserved words

Extern (Reserved word)

In french: Externe

EXTERN is used to:

Include a text file containing WLanguage commands in an application (see syntax 1). This feature is only available in the initialization code of the project, in the declaration code of the global variables of a window/page and in the declaration code of a class.
Declare an external object (see syntax 2).
Declare a JavaScript object in WLanguage code.

Versions 16 and later

This feature is available for Windows Phone applications.

New in version 16

This feature is available for Windows Phone applications.

Versions 17 and later

This feature is available for iPhone/iPad applications.

New in version 17

This feature is available for iPhone/iPad applications.

Versions 18 and later

This feature is available in Windows Store apps mode.

This feature is available in Android widget mode.

New in version 18

This feature is available in Windows Store apps mode.

This feature is available in Android widget mode.

This feature is available in Windows Store apps mode.

This feature is available in Android widget mode.

Versions 20 and later

The integration of a text file containing WLanguage code is now available in browser code.

New in version 20

The integration of a text file containing WLanguage code is now available in browser code.

Versions 21 and later

This feature is available in Universal Windows 10 App mode.

This feature is available in Apple Watch mode.

New in version 21

This feature is available in Universal Windows 10 App mode.

This feature is available in Apple Watch mode.

This feature is available in Universal Windows 10 App mode.

This feature is available in Apple Watch mode.

Example

// Syntax 1
// Include the "WinConst.wl" file that contains the standard Windows constants
EXTERN "WinConst.wl"

// Syntax 2
EXTERN ExampleWindow
LoadWDL("User1.WDL")
Open(ExampleWindow)

// Allows you to use the JavaScript Document object in WLanguage code
EXTERN document

pclObject is object dynamic
pclObject = document:getElementById("id_object")

Syntax

Including a text file in an application Hide the details

EXTERN <File name>

<File name>: Character string

Name of text file containing the WLanguage code that must be included in an application. This is a standard text file, created by any text editor.
A full path can be specified (for example: "C:\WDProject\MyConst.wl"). If the path is not specified, the file will be sought:
in the project directory,
in the "Personal\Extern" directory of WINDEV, WEBDEV and WINDEV Mobile.
Including a text file with EXTERN has the same effect than copying a text file in the code editor.

Declaring an external object Hide the details

EXTERN <Name of External Object>

<Name of external object>: Character string

Name of external object (variable, constant, ...) to declare.
EXTERN is used to declare a variable that will exist only when running the application.
For example, the EXTERN keyword can be used to handle a window found in an external library (loaded by LoadWDL).
EXTERN can be used to handle the JavaScript objects in WLanguage browser code.

Remarks

Including constants

Including files is very useful to describe the constants common to several projects or used by the operating system. Use EXTERN to include in the code a file containing the common constants.
Including files can only be performed in the following processes:
- Initialization code of project,
- Declaration code of global variables of window or page,
- Declaration code of class.
Several files defining the constants are supplied (in the "\Personal\Extern" subdirectory of WINDEV, WEBDEV or WINDEV Mobile):
- "WinConst.wl": Standard Windows constants.
- "Limites.wl": Constants corresponding to the limits for the types of WINDEV, WEBDEV and WINDEV Mobile data.
- "ListeDefinitionHF.wl": HFSQL constants used for the log process (see Files handled by the log process).
- "Except.wl": Constants used to manage the exceptions.
- "KeyConst.wl": Standard Windows constants used for the keyboard keys. These constants can be used with KeyPressed in the optional WINDEV processes ("Key down" or "Key up") by using the _EVE.wParam variable.

Deploying the application

When installing the application on the client computer:

If the path of the file is specified: The file must be installed in the specified directory.
If the path of the file is not specified: By default, the file will be automatically installed in the directory of the project.