Ramil,

I would change

      cNeeds = cNeeds + DoubleToStr(dNeeds[i])
* to
      cNeeds = cNeeds + DoubleToStr(dNeeds[i] * 1.0)

to make sure that's double.

>Hi Sergey/Anotoliy:
>
>This contains a detailed explanation of my problem, containing code snippets (long thread). Just deal with this if you have free time. Many thanks in advance.
>
>Problem summary: The return array, dStart, is not populated with the correct values. Not even sure if the dNeeds array is properly passed/received by the API, eventhough the API did not return error value.
>
>I noticed that the array wasn't actually passed in VB, just the first element. This is
>how it was defined in VB:
>

>'------------------------------------------------------------
>' This is in a module file: module1.bas
>'------------------------------------------------------------
>Public Declare Function LScreateEnvLng _
>Lib "LINGD80.DLL" () As Long
>Public Declare Function LSsetPointerLng _
>Lib "LINGD80.DLL" (ByVal pLINGO As Long, ByRef dObject As Double, _
>ByRef nPointersNow As Long) As Long
>
>'------------------------------------------------------------
>' The following codes are in a click event of a form that accepts the values of dNeeds
>'------------------------------------------------------------
>' Create the LINGO environment object
>' Assume that the environment will be created successfully
>   Dim pLINGO As Long
>   pLINGO = LScreateEnvLng()
>
>dim dNeeds(7) as double
>' sample value of dNeeds; this is entered through textboxes
>' dNeeds(1)=2
>' dNeeds(2)=3
>' dNeeds(3)=1
>' dNeeds(4)=1
>' dNeeds(5)=2
>' dNeeds(6)=2
>' dNeeds(7)=2
>
>Dim dStart(7) As Double
>
>' nPointersNow is not even defined!
>' @POINTER(1) this is the receiving entity of the API
>   nError = LSsetPointerLng(pLINGO, dNeeds(1), nPointersNow)
>   If nError <> 0 Then GoTo ErrorExit
>
>' @POINTER(2) this is the receiving entity of the API
>   nError = LSsetPointerLng(pLINGO, dStart(1), nPointersNow)
>   If nError <> 0 Then GoTo ErrorExit
>
>' there is a script here to run the LINGO model
>' nError does not return <> 0 (meaning successfully ran the model).
>
>' assign returned values to textboxes
>' clean up codes
>
>ErrorExit:
>  ' clean up codes
>
>

>
>In the first pointer, I just need to pass the values of dNeeds to the API, but in the second pointer, I need to get the values filled-in by API.
>
>I've used CLSHEAP functions: CopyDoubleToString & DoubleToNum to convert the data back and forth.
>
>This is a snippet of my VFP code:
>

>*------------------------------------------------
>* LINGO API
>*------------------------------------------------
>declare integer LScreateEnvLng in "c:\lingo8\lingd80.dll"
>declare long LSsetPointerLng in "c:\lingo8\lingd80.dll" long, string @, integer @
>
>*------------------------------------------------
>* conversion APIs:
>*------------------------------------------------
>* converts double to number
>declare RtlMoveMemory in WIN32API as ConvDoubleToNum ;
>	double @DestNumeric, ;
>	string @pVoidSource, ;
>	integer nLength
>*  converts double to string
>declare RtlMoveMemory in WIN32API as ConvDoubleToStr ;
>	string @DestString, ;
>	double @pVoidSource, ;
>	integer nLength
>
>*------------------------------------------------
>* conversion API implementation:
>*------------------------------------------------
>*  converts double to string
>function DoubleToNum
>	lparameter cDoubleInString
>	local nNum
>	nNum = 0.000000000000000000
>	=ConvDoubleToNum(@nNum, cDoubleInString, 8)
>	return nNum
>endfunc
>function DoubleToStr
>	lparameter nDoubleToCopy
>	local cString
>	cString = space(8)
>	=ConvDoubleToStr(@cString, nDoubleToCopy, 8)
>	return cString
>endfunc
>
>*------------------------------------------------
>* click event of my test form
>*------------------------------------------------
>with thisform
>* create the LINGO environment
>   .pLINGO = LScreateEnvLng()
>   if .pLINGO = 0
>      messagebox('Unable to create environment')
>      return .f.
>   endif
>   local nError as long
>   private nPointersNow
>   nPointersNow = 0
>
>   * pointer 1; dNeeds array is the values of the textboxes of my test form
>   * assume that these data are properly assigned.
>   private cNeeds
>   cNeeds = ''
>   for i = 1 to 7
>      cNeeds = cNeeds + DoubleToStr(dNeeds[i])
>   endfor
>   * pointer 1; array to be passed to API
>   nError = LSsetPointerLng(.pLINGO, @cNeeds, @nPointersNow)
>   if nError <> 0
>      set step on
>   endif
>   * pointer 2; array to be updated with values from API
>   dimension dStart[7] as double
>   dStart = 0.0
>   private cStart
>   cStart = ''
>   for i = 1 to 7
>      cStart = cStart + DoubleToStr(0.0)
>   endfor
>   nError = LSsetPointerLng(.pLINGO, @cStart, @nPointersNow)
>   if nError <> 0
>      set step on
>   endif
>   * run the LINGO script here, returns <> 0 which means successful
>   * these values are not the same as the values returned in the VB sample
>   * by this magnitude
>   * VB=1 vs VFP=0.38E-300!!!
>   .text8.value=DoubleToNum(substr(cStart,1,8))
>   .text9.value=DoubleToNum(substr(cStart,9,8))
>   .text10.value=DoubleToNum(substr(cStart,17,8))
>   .text11.value=DoubleToNum(substr(cStart,25,8))
>   .text12.value=DoubleToNum(substr(cStart,33,8))
>   .text13.value=DoubleToNum(substr(cStart,41,8))
>   .text14.value=DoubleToNum(substr(cStart,49,8))
>
>