umanaged code - array error

[Patrick Sullivan]

dim s_err as stringbuilder
dim xx(6) as double
dim ret_flag as integer

' This is a function to call an unmanaged C-style library function.
' The lib function fills an array of 6 doubles or error string.

Declare Auto Function calc Lib "calc32.dll" Alias "calc32.dll"( ByRef xx()
As Double, ByVal serr As System.Text.StringBuilder) As Integer

' Using the unmanaged function:

ret_flag = swe_calc(tjd_et, planet, iflag, xx(6), serr)

If I take out the 6 in the above line, I get error "number of indices is
less than the number of dimensions in the indexed array."

If I put it in, or put a zero in, like xx(0) or xx(6), I get the error
"value of type double cannot be converted to '1 dimensional array of
double'"

What is wrong here? TIA

 

[Patrick Sullivan]

dim s_err as stringbuilder
dim xx(6) as double
dim ret_flag as integer

' This is a function to call an unmanaged C-style library function.
' The lib function fills an array of 6 doubles or error string.

Declare Auto Function calc Lib "calc32.dll" Alias "calc32.dll"( ByRef xx()
As Double, ByVal serr As System.Text.StringBuilder) As Integer

' Using the unmanaged function:

ret_flag = swe_calc(xx(6), serr)

If I take out the 6 in the above line, I get error "number of indices is
less than the number of dimensions in the indexed array."

If I put it in, or put a zero in, like xx(0) or xx(6), I get the error
"value of type double cannot be converted to '1 dimensional array of
double'"

What is wrong here? TIA

 

[Larry Lard]

dim s_err as stringbuilder
dim xx(6) as double
dim ret_flag as integer

' This is a function to call an unmanaged C-style library function.
' The lib function fills an array of 6 doubles or error string.

Declare Auto Function calc Lib "calc32.dll" Alias "calc32.dll"( ByRef xx()
As Double, ByVal serr As System.Text.StringBuilder) As Integer

' Using the unmanaged function:

ret_flag = swe_calc(xx(6), serr)

Copy-and-pasting code is a much more reliable way of showing us your
code. Note that the Declare calls the function 'calc' but you call it
as 'swe_calc'. If we have to guess what you mean, it will take us
longer to help you.

If I take out the 6 in the above line, I get error "number of indices is
less than the number of dimensions in the indexed array."

If I put it in, or put a zero in, like xx(0) or xx(6), I get the error
"value of type double cannot be converted to '1 dimensional array of
double'"

Try

ret_flag = calc(xx, serr)

The function wants an array: it is xx - not xx(0) or xx(6) or xx() -
that is an array.

Also, xx should be initialised to an empty array before calling the
DLL, otherwise there will be nowehere to put the results:

xx = New Double(6) {}

Also also, all I have fixed is the syntax: I don't know enough about
calling unmanaged code to be able to say that this will definitely do
what you want.

 

[Patrick Sullivan]

Thanks Larry. You figured out what I wanted to know, I think. Interop is
kind of confusing. It took me quite a while to get the s_err to pass
compiling.

 

[=?ISO-8859-1?Q?G=F6ran_Andersson?=]

You are declaring an array of 7 doubles. To declare an array of 6
doubles, you have to do like this:

dim xx(5) as double