On Sat, 6 Jun 2015, luciano de souza wrote:
Hello all,
At work, I need to create a Excel sheet containing certain more
complex functions. I tried to use only VBA, but I released I will more
productive if I could use a DLL writen in Pascal for the heavier code.
Let see this DLL:
library test;
{$mode objfpc}{$H+}
function concatenate(name: string): string; cdecl;
begin
result := 'Freepascal ' + name;
end;
function first(names: array of string):string; cdecl; // Warning:
cdecl'ared functions have no high parameter
I very much doubt VBA understands the 'array of string' concept.
It is typical for pascal.
begin
result := names[0];
end;
exports
concatenate;
first;
end.
The compiler also raised this error: "test.pas(10,1) Fatal: Internal
error 201003031".
I don't know what I am doing wrong. But actually, the reason of my
message started from another point.
Freepascal codes works with strings as usual. DLLs works with pchar. I
could have declared the functions as the following:
function concatenate(name: pchar): pchar; cdecl;
function first(names: array of pchar): pchar; cdecl;
I think you need to use stdcall calling convention.
In the body of the functions, I would treat the conversions from pchar
to string and from string to pchar again. But, when I used "cdecl", am
I making this conversion automatically? Is there a compilation switch
that allows me to write strings and the compiled code having correctly
treated the allocations and disallocation of strings?
No, there is not.
Suppose this VBA code:
public declare function concatenate lib "test" (name as string) as string
Is this the correct way to write the called function in Freepascal?
function concatenate(name: string): string; cdecl;
begin
result := 'Freepascal ' + name;
end;
No, IMHO you will need to use pchar everywhere.
Michael.
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