ZBasic Forum

Posted: **22 January 2010, 0:00 AM**

Hello,

I defined a Structure with a large number of members. Some of the members include arrays. I defined a separate function to operate on an array, but don't want to pass the entire Structure to preserve speed. Is this possible? The following example fails to compile:

Code: Select all

option base 1

Structure bar 
   Dim i as Integer 
   Dim a&#40;1 to 3&#41; as Integer
End Structure 


Sub Main&#40;&#41; 
   Dim b1 as bar 
   Dim i  as Integer 

   i = foo&#40;b1.a&#41; 

   debug.print "i=" & i
End Sub 


Function foo&#40;ByRef b&#40;&#41; as Integer&#41; as Integer
  foo = b&#40;1&#41;+b&#40;2&#41;+b&#40;3&#41;
End Function

Appreciate your comments.

Liam

Posted: **22 January 2010, 6:37 AM**

It looks like the compiler does have a problem with this code. The following might be a possible workaround. Note that it is untested as I do have a ZX device with me right now.

Code: Select all

Sub Main&#40;&#41;
   Dim b1 as bar
   Dim i as Integer

   i = foo&#40;MemAddressU&#40;b1.a&#41;&#41;

   Debug.Print "i=" & i
End Sub

Function foo&#40;ByVal addr as UnsignedInteger&#41; as Integer
  Dim b&#40;&#41; as Integer Based addr
  foo = b&#40;1&#41;+b&#40;2&#41;+b&#40;3&#41;
End Function

Posted: **22 January 2010, 8:35 AM**

liam.zbasic wrote: don't want to pass the entire Structure to preserve speed.

It makes no difference. Passing an array and a structure are both done using a reference behind the scenes, whether ByRef or ByVal. The code below compiles without error.

Code: Select all

option base 1
Structure bar
   Dim i as Integer
   Dim a&#40;1 to 3&#41; as Integer
End Structure

Sub Main&#40;&#41;
   Dim b1 as bar
   Dim i  as Integer

   i = foo&#40;b1&#41;
   debug.print "i=" & i
End Sub

Function foo&#40;ByRef b as bar&#41; as Integer
  foo = b.a&#40;1&#41;+b.a&#40;2&#41;+b.a&#40;3&#41;
End Function

liam.zbasic wrote:The following example fails to compile:

This is a known problem that has already been corrected. We are in the final stages of preparing a new release.

ZBasic Forum

Passing a Member of Structure

Passing a Member of Structure

Re: Passing a Member of Structure