Thanks Randy for your time.
   I did some experiment, got it working finally.
   by default any numeric value changed to variant inside subroutine
   wxception were string and array since they use pointers so they required
   explicit conversion inside vb subroutine

-----Original Message-----
From: Randy Cornish [mailto:rlcornish@c...]
Sent: Saturday, January 19, 2002 8:43 AM
To: professional vb
Subject: [pro_vb] Re: Strings and variant


I had a hard time following the example, so I may be off base here, but 
the short of the matter is - ByRef parameters need to ahve the same EXACT 
datatype.  There is no type coercion when using ByRef.  Therefore, in 
example 2, you are mixing a String and a Variant.  VB won't allow unless 
it is ByVal.

>   I need to return(byref) string type from vbsubroutine from Vb dll.
>   
> 1) works
> 
>   Private Declare Sub ETBORE Lib "EtolTabl.dll" (ByRef TolHi As
> Single,...,..)
> 
>   Public Sub vbETBORE(ByRef TolHi,...,..)
> 	Call ETBORE(TolHi,...,..)
>   End Sub
> 
>    Above sample works but only when argument is string type it gives 
type
> mismatch.
> 
>  
> 2) fail to work
> 
>   Private Declare Sub getc0 lib "round.dll" (ByRef cone_type As
> String,...,..)
> 
> 	Public Sub vbGetConeId(byref cone_type,...,..)
> 	   Call getconeid(cone_type,...,..)  //Type mismatch
> 	End Sub
> 
>   Does VB variant handles string differently than other datatypes.
>  



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