我如何通过一个数组（通过引用VB6）为C \ C ++的* .dll子程序？ [英] How do I pass an Array (By Reference, in VB6) to a C\C++ *.dll subroutine?

问题描述

我需要通过变体的空数组以C语言编写的（和适用于所有Windows版本）一个DLL，而C code（这是我无法控制的，不能编辑）将填充空数组变体，其某些函数的返回值。

I need to pass an empty Array of Variants to a DLL written in C (and available on all Windows versions), and the C code (which I have no control over and cannot edit) will populate the Empty Array of Variants with its some return values.

Bascially，当我尝试这 - 的ByRef的数组总是空的，当它应该包含函数/子调用的结果（如果我在.NET中完全一样的东西，它的工作原理）

Bascially, when I try this - the ByRef Array is always empty when it should contain the results of the function/sub call (if I do the exact same thing in .NET, it works).

我想我需要做一个自定义的声明，使VB知道如何调用C函数，或？

I'm thinking I need to do a custom declaration so VB knows how to call the C function, or?

下面是如何在c子/函数声明。鉴于此，我需要什么做的，为了保证C是能够正常，我用我的空数组的燕鸥得到结果回来？

Here is how the C sub/function is declared. Given this, what do I need to do in order to ensure C is able to use my Empty Array properly and I in tern get my results back?

HRESULT InvokeAction(
  [in]       BSTR bstrActionName,
  [in]       VARIANT varInActionArgs,
  [in, out]  VARIANT *pvarOutActionArgs,
  [in, out]  VARIANT *pvarRetVal
);

有关此功能的更多信息：的http：// MSDN .microsoft.com / EN-US /库/ aa382237（VS.85）的.aspx

感谢

推荐答案

从的 http://msdn.microsoft.com/en-us/library/aa381230（VS.85）的.aspx ：

Dim returnVal
Dim outArgs(1)
Dim args(1)
args(0) = 3
returnVal = service.InvokeAction("GetTrackInfo", args, outArgs)
'return Val now contains the track length
'and outArgs(0) contains the track title
Dim emptyArgs(0)
returnVal = service.InvokeAction("Play", emptyArgs, emptyArgs)
'returnVal indicates if the action was successful

您究竟获得和服务的实例是不是从这个例子虽然。

Just how you get and instance of service is not clear from this example though.

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