Calling external routines

Sprut4 can call external subroutines from dynamic link libraries (dlls). Define a function or procedure with external keyword to create a link between sprut4 routine and external function.

Sprut4 uses stdcall calling convention. Integer parameters are passed as 4-byte signed integer. Float parameters are passed as 8-byte floating point value. String paramters are passed as a sequence of unsigned chars (pointer to the first char is passed). Olebstr parameters are passed as BSTR (pointer to BSTR for var parameters).

Syntax:

procedure[function] foo(<parameters_list>)[: <result_type>] external <dll_name> name <routine_name_in_dll_export>

foo - name of procedure or function.

parameters_list - list of semicolon separated procedure parameters. only generic integer, float, pointer, string and olebstr types are supported. String parameters are passed read-only. to pass var string-type parameter to external procedure use olebstr type. Olebstr type is a OLE Automation BSTR.

result_type - type of function returned value. only generic integer, float, pointer, olebstr types are supported. String return values must be of olebstr type.

<dll_name> - constant string expression, defines file name of dynamic link library.

<routine_name_in_dll_export> - constant string expression, routine name in export table of dll.

Example

Visual C++

#include "stdafx.h"

#include <stdio.h>

#include <Windows.h>

#include <OleAuto.h>

extern "C" 

{

 BSTR __declspec(dllexport) __stdcall test_func(int i, double d, BSTR str, BSTR* refstr)

 {

         wchar_t msg[1000];

         swprintf(msg, 500,  L"passed params:\r int: %i\r double: %f\r str: %s\n", i, d, str);

         BSTR myBstr = 0;

         myBstr = SysAllocString(msg);

         SysReAllocString(refstr, L"string by ref");

         return myBstr;

 }

}

Delphi

library test_params;
uses
  System.SysUtils,
  Winapi.Windows,
  ActiveX;
 
function test_func(  Int: Integer; Flt: Double; Str: TBSTR; var RefStr: TBSTR): TBSTR; stdcall;
var
  S: string;
begin
  S := 'integer: ' + IntToStr(Int) + #13#10
    + 'float(As Double): ' + FloatToStr(Flt) + #13#10
    + 'string: ' + Str;
  SysReAllocString(RefStr, 'update str');
  Result := SysAllocString(S);
end;

 
exports
  test_func;
 
begin
end.