How to get pointer to a string stored in an array element?

[just me]

@Helgef,
interesting concept. I'm still struggling with the new objects. Finally I chose something similar:

Code: Select all

   RBArr := []
   RBBuf := Buffer(TDBSize * RBCnt, 0) ; C array of TASKDIALOG_BUTTON structures
   Addr := RBBuf.Ptr
   For I, V In Radios {
      Buf := Buffer((StrLen(V) + 1) * 2, 0)
      StrPut(V, Buf.Ptr)
      RBArr.Push(Buf)
      Addr := NumPut("Int", MinRID + I, "Ptr", Buf.Ptr, Addr)
   }

Thanks!

[xroot]

@just me
Looking @ your first example how about this:

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Arr := [StrPtr("Hello!"),StrPtr("Olleh!")]

;Ptr1 := StrPtr(Arr[1])
;Ptr2 := StrPtr(Arr[2])

MsgBox Arr[1] " " StrGet(Arr[1]) 

[just me]

@xroot, it would work, but it would be an array of pointers not an array of strings.

[Helgef]

I think Lexikos also says that it wont be a race condition (implicitly).
[...]
Notice the use of a temporary string buffer here.

The life time of string pointers are described, explicitly, in the documentation for strptr. In particular,

The address of a literal string is valid until the program exits. The script should not attempt to modify the string.

Cheers.

[kczx3]

Like I said

[lexikos]

I think the reasons I chose to remove GetAddress entirely rather than replacing it with multiple methods (like GetPropAddress and GetItemAddress) were:

• Further increasing cost for each type of "container" that can provide a string address. More code and documentation to write, test and maintain. More special cases for users to remember.
• I tentatively plan to experiment with reference-counted strings, which would ideally improve performance and enable StrPtr to be used (relatively) safely with strings from any container.
• There are efficient alternatives. While you may need a pointer to a string, you don't truly need that string to be contained by an array or property.

I think there's a stronger case for using arrays this way than properties or maps, so depending on how v2.1 develops, I might consider restoring GetAddress for arrays.

In retrospect, the capabilities previously present in SetCapacity and GetCapacity may have biased me toward removing GetAddress. Effectively duplicating the functionality of a Buffer into every property, array element and map item is somewhat less appealing than providing a simple method to efficiently utilize strings already stored in an array.

[xroot]

@just me
Try using a SafeArray, this might solve your strptr issue.

Code: Select all

;arr    := ["Hello!","Olleh!"]

arr    := ComObjArray(12,2)
arr[0] := "Hello!"
arr[1] := "Olleh!"

ptr1 := StrPtr(arr[0])
ptr2 := StrPtr(arr[1])

MsgBox ptr1 " " StrGet(ptr1) " " ptr2 " " StrGet(ptr2)