Visual Basic 2005 in a Nutshell, Third Edition

Call Statement | 183

The Language

Reference

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Example

Public Sub Main( )

DoSomeLongFunction( )

Beep( )

MsgBox("Finished!")

End Sub

Call Statement

Syntax

[Call] procedureName([argumentList])

procedureName (required)

The name of the subroutine being called

argumentList (optional)

A comma-delimited list of arguments to pass to the subroutine being called

Description

The Call statement passes execution control to a procedure, function, or dynamic-link

library (DLL) procedure or function.

Usage at a Glance

• Use of the Call keyword is optional.

• argumentList, if present, must always be enclosed in parentheses.

• If you use Call to call a function, the function’s return value is discarded.

Example

Call SomeProcedure(True, importantData)

...later...

Public Sub SomeProcedure(ByVal silentFlag As Boolean, _

ByVal workData As Integer)

...

End Sub

Version Differences

• In VB 6, calls to subroutines only included parentheses around the argument list

when the

Call keyword was included. In .NET, parentheses are required when-

ever arguments are present.

• In VB 6, when calling an external routine defined using the

Declare statement,

you could override the defined method of passing an argument by specifying the

ByVal or ByRef keywords before the argument in the Call statement. In .NET, you

cannot change the argument-passing ...