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GoFiler Legato Script Reference

 

Legato v 1.5b

Application v 5.24b

  

 

Chapter FourFlow Control (continued)

RunBackgroundScript Function

Overview

The RunBackgroundScript loads a specified script and runs the script from an optional entry point as a background thread. Optional parameters can be passed to the target script. After processing the target script is unloaded.

Syntax/Parameters

Syntax

handle = RunBackgroundScript ( string name, [string function], [parameters ...] );

Parameters

name

A string containing the name of the script to run. If name contains a qualified path, that file is loaded and run from that location. If the path is not qualified, it is resolved using the calling scripts main module path.

function

A string containing the name of the function to run. If omitted or empty, the default entry point is located and run. If there is no default function such as “main” or “entry”, the script will be run from an unstructured entry point in which case the parameters will not be retrievable by the executed script.

parameters

Zero or more optional parameters to pass to the script. Variables cannot be passed by reference. When parameters are employed, the function parameter must be provided. However, it can be a simple "" empty string. Only certain types of handles cannot be passed, see Remarks below for details.

Return Value

Returns a handle to the created thread or NULL_HANDLE on failure. Use the GetLastError function to retrieve a formatted error code.

Remarks

The RunBackgroundScript function loads the script and runs it from the specified point. A new thread is created for the specified script. Once the new script engine has been created, the RunBackgroundScript will return immediately with a handle or an error. If the provided script contains errors, the function will still return a handle and the errors will be processed by the background manager. In such a case, the thread will terminate nearly immediately.

See Section 4.14 Control and Background Processes for more information.

Certain restrictions apply to the background script. First and foremost is that background scripts (or any thread) cannot execute in the primary thread’s message loop. Because of this, modal dialogs and message boxes are not allowed. The MessageBox function can be used but will post a request to the frame and immediately return to the calling script. Background scripts can send messages to windows and execute SDK functions that require messages but the message must be run in the primary process thread. If the thread is busy (such as running another script), the background thread will be suspended until the message can be processed.

When passing a parameter as a handle, only global or Windows handles can be passed. For example, a handle to an object that is owned by the current script cannot be passed and used by the receiving script. However, the script handle can be passed.

Related Functions

Platform Support

Go13, Go16, GoFiler Complete, GoFiler Corporate, GoFiler, GoFiler Lite, GoXBRL

Legato IDE, Legato Basic