Return a TYPE from a function call

[Mike Trader]

Lets say I want to call a function and send it a long and return a TYPE. What is the accepted way of handling that?

for example: Lets say i have loaded up an array of my type and now i want to retrieve a value:

snip ..

TYPE FuncVarType
TSPrice AS SINGLE
SPr1 AS SINGLE
SPn1 AS SINGLE
Diff AS SINGLE
SPr2 AS SINGLE
END TYPE

GLOBAL FuncVar AS FuncVarType
GLOBAL FuncVarStack() AS FuncVarType
'¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
FUNCTION GetFuncVars(BYVAL LkBk AS LONG) AS FuncVarType ' Retrieve TYPE from the Push Stack

IF LkBk > NumElem THEN MSGBOX("Error") : EXIT FUNCTION
IF LkBk <= Index - 1 THEN
FUNCTION = FuncVarStack(Index - 1 - LkBk)
ELSE
FUNCTION = FuncVarStack(NumElem + Index - LkBk)
END IF
END FUNCTION

this will not compile because of
FUNCTION GetFuncVars(BYVAL LkBk AS LONG) AS FuncVarType


So how do you return a TYPE from a function?


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Kind Regards
Mike

[Aldo Cavini]

You can't return a type from a function. You can pass it as a parameter. Say:

Function GetFuncVars( BYVAL LkBk AS LONG, FuncVar AS FuncVarType ) as long

You will use FuncVar inside the function, and get the modified values after the call. The return value can be ignored, or you can return a completion code, or something else...



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[Edwin Knoppert]

Our use a static and return a pointer

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[Tom Hanlin]

STATIC variables should not generally be used for return buffers, as this will
lead to problems if your function may be called recursively, from multiple threads,
or in various other situations where the buffer may be changed before you have a
chance to use it!

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Tom Hanlin
PowerBASIC Staff

[Peter Manders]

You can return a string like this:

FUNCTION GetFuncVars(BYVAL LkBk AS LONG) AS STRING ' Retrieve TYPE from the Push Stack
'whatever
END FUNCTION

and call it like this:

LSET MyType = GetFuncVars(SomeValue)


Peter


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[email protected]

[Mike Trader]

Ok thx,

I think i like option A

Aldo,

This is passing the TYPE BYREF right? that way I can get the changed values from the calling function

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Kind Regards
Mike

[Lance Edmonds]

UDTs are always passed BYREF, never BYVAL.

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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>