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What is the purpose of LPARAMETERS
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À
12/06/2014 13:22:40
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows Server 2012
Network:
Windows 2008 Server
Database:
MS SQL Server
Application:
Web
Divers
Thread ID:
01601772
Message ID:
01601802
Vues:
41
>>>If you recall PRIVATE scope is hierarchical - visible down from where a variable is declared all the way into child functions/methods called. LOCAL scope is local to the function the variable is declared at. So LPARAMETERS limits the scope of the parameters - where they are visible - to the function they are declared in.
>>>
>>>It has nothing to do with passing by value or by reference.
>
>Just to add to Rick's comments, what LPARAMETERS does is hide the variable from anything called by this routine. That is, the difference is relevant in this case:
>
>
>MyProc1(42)
>
>PROCEDURE MyProc1
>PARAMETERS nNum
>
>MyProc2()
>?m.nNum  &&  37
>
>RETURN
>
>PROCEDURE MyProc2
>
>* Refer to nNum
>nNum = 37
>
>RETURN
>
>
>and:
>
>
>PROCEDURE MyProc1
>LPARAMETERS nNum
>
>MyProc2()
>?m.nNum && 42
>
>RETURN
>
>PROCEDURE MyProc2
>
>* Refer to nNum without declaring it
>nNum = 37
>
>RETURN
>
>
>In the first example, nNum in MyProc1 is changed by MyProc2. In the second, it's not.
>
>Tamar

Thank you.
"The creative process is nothing but a series of crises." Isaac Bashevis Singer
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