德尔福到C DLL：传递数组 [英] Delphi-to-C dll: Passing Arrays
问题描述
我使用德尔福加载DLL（即我在Delphi XE-3中创建），与一些C code接口的目的。我的问题是搞清楚为什么我的数组没有被传递到C函数 - 他们是唯一没有。德尔福文件（简体）看起来是这样的：
程序CALLC code
用途
SysUtils单元时，Windows，
在DLLUnit.pas'DLLUnit; //头转换VAR
DLLHandle：基数;
n：整数;
答：在tarray＆LT;整数取代;
RESULT1：整数;开始
//初始化每个阵列
SetLength函数（A，N）;
A [0] = ...; //加载DLL（并确认其加载）
DLLhandle：=的LoadLibrary（'dllname.dll'）;
如果DLLhandle＆LT;＆GT; 0，则
开始
RESULT1：= dll_func1（N，A）; // A和B不正确传递
结束
FreeLibrary则（DLLHandle）;
结束。
我成功跟踪到dll_func1首次进入DLLUnit，其中有：
常量
nameofDLL ='的Dllname';
功能dll_func1（n：整数; A：在tarray＆LT;整数GT）：整数; CDECL;外部nameofDLL;
跟踪-变成再说一次，我到达C文件，仍然有正确的n和DLLdefs值，但A（根据局部变量标题）已经成为：
[ - ]答：（APLHA数字）
.. [0] 0（00000000）
我知道我至少访问该DLL（希望）正确，因为其他函数调用的工作，因为他们应该和我能够追查到dll_func1.c文件没有问题。我试图改变功能
函数dll_func1（n：整数; A：PInteger）：整数; CDECL;外部nameofDLL;
...
RESULT1：= dll_func1（N，PInteger（A））
或
函数dll_func1（n：整数; A：PInteger）：整数; CDECL;外部nameofDLL;
...
RESULT1：= dll_func1（N，@ A [0]）
（同时使用在tarray和整数数组或一个），但没有任何改变，这让我相信这是有关我没有看到一个问题。整个事情编译和运行，但RESULT1是因为在tarray失败不正确。关于什么错误任何想法？
修改 C语言中的功能：
INT dll_func1（INT N，INT A []）
您的问题包含外部函数的两个德尔福声明。其中一人使用在tarray＆LT; T＆GT; 作为参数。这是完全错误的。不要那样做。您不能使用一个Delphi动态数组作为互操作类型。原因是，在tarray＆LT; T＆GT; 是只能被创建和德尔福code消耗了复杂的托管类型
您需要做的，因为我做以下，正如我在回答解释你的previous问题，声明数组参数作为指针元素类型。例如， PInteger ， PDouble 等
有相当大量的混乱在这里，和不必要的复杂性。你需要的是一个最简单的例子，说明如何从你的Delphi code数组传递到C code。
下面则是
C $ C $ç
// testarray.c无效printDouble（双D）; //连接器就会根据德尔福code解决此无效试验（双*改编，诠释计数）
{
INT I;
对于（i = 0; I＆LT;计数;我++）
{
（ARR [I]）printDouble;
}
}
德尔福code
程序DelphiToC;{$ APPTYPE CONSOLE}用途
CRTL;程序_printDouble（D：双人间）; CDECL;
开始
Writeln（四）;
结束;程序测试（ARR：PDouble;计数：整数）; CDECL;外部名称'_test';{$ L testarray.obj}VAR
ARR：在tarray＆LT;双取代;开始
ARR：=在tarray＆LT;双＆GT; .Create（1.0，2.0，3.0，42.0，666.0）;
测试（PDouble（ARR），长度（ARR））;
Readln;
结束。
编译使用C code，例如，Borland的C编译器是这样的：
bcc32 -c testarray.c
和输出是：
1.00000000000000E + 0000
2.00000000000000E + 0000
3.00000000000000E + 0000
4.20000000000000E + 0001
6.66000000000000E + 0002
请注意，我联系到C code静态，因为这对我来说更容易。没有什么太大的变化，如果你把C code下的DLL。
结论是，code我给你在我回答你的previous，而且我在这里重复，是正确的。这种方法成功地通过德尔福code到C数组它看起来像你的诊断和调试是错误的。
您只检查 A [0] 所以这并不奇怪，你只能看到一个值。如果只有你会看 A [1] ， A [2] ... A [N-1] 你会看到，所有的值都被正确传递。或者，也许你的调试于所使用的外部函数的错误声明进行了在tarray＆LT; T＆GT; 作为参数
I'm using Delphi to load a dll (that I created in Delphi XE-3) for the purposes of interfacing with some C code. My problem is figuring out why my arrays aren't being passed to the c functions - they're the only ones not to. The delphi file (simplified) looks like this:
program CallcCode
uses
SysUtils, Windows,
DLLUnit in 'DLLUnit.pas'; // Header conversion
var
DLLHandle: cardinal;
n: Integer;
A: TArray<Integer>;
result1: Integer;
begin
// Initialize each Array
SetLength(A,n);
A[0] = ...;
// Load the DLL (and confirm its loaded)
DLLhandle := LoadLibrary('dllname.dll');
if DLLhandle <> 0 then
begin
result1 := dll_func1(n,A); // A and B are not passed correctly
end
FreeLibrary(DLLHandle);
end.
I successfully "Trace into" dll_func1 the first time, entering DLLUnit, which has:
const
nameofDLL = 'dllname';
function dll_func1(n: Integer; A: TArray<Integer>): Integer; cdecl; external nameofDLL;
"Tracing-into" again, I arrive at the c file, which still has the correct n and DLLdefs values, but A (under the "Local Variables" heading) has become:
[-] A :(Aplha-Numeric)
..[0] 0 (0x00000000)
I know that I'm at least accessing the DLL (hopefully) correctly because other function calls work as they should and I am able to trace into the dll_func1.c file without a problem. I tried changing the function to
function dll_func1(n: Integer; A: PInteger): Integer; cdecl; external nameofDLL;
...
result1 := dll_func1(n,PInteger(A))
or
function dll_func1(n: Integer; A: PInteger): Integer; cdecl; external nameofDLL;
...
result1 := dll_func1(n,@A[0])
(using both TArray and array of Integer or A) but there is no change, which leaves me to believe this is related to a problem I'm not seeing. The whole thing compiles and runs, but result1 is incorrect because of the TArray failures. Any ideas on what is going wrong?
EDIT The function in C as:
int dll_func1(int n, int A [])
Your question contains two Delphi declarations for the external function. One of them uses TArray<T> as a parameter. That is completely wrong. Don't do that. You cannot use a Delphi dynamic array as an interop type. The reason being that TArray<T> is a complex managed type that can only be created and consumed by Delphi code.
You need to do as I do below, and as I explained in my answer to your previous question, and declare the array parameter as pointer to element type. For example, PInteger, PDouble, etc.
There's quite a lot of confusion here, and needless complexity. What you need is the simplest possible example that shows how to pass an array from your Delphi code to C code.
Here is is.
C code
//testarray.c
void printDouble(double d); // linker will resolve this from the Delphi code
void test(double *arr, int count)
{
int i;
for (i=0; i<count; i++)
{
printDouble(arr[i]);
}
}
Delphi code
program DelphiToC;
{$APPTYPE CONSOLE}
uses
Crtl;
procedure _printDouble(d: Double); cdecl;
begin
Writeln(d);
end;
procedure test(arr: PDouble; count: Integer); cdecl; external name '_test';
{$L testarray.obj}
var
arr: TArray<Double>;
begin
arr := TArray<Double>.Create(1.0, 2.0, 3.0, 42.0, 666.0);
test(PDouble(arr), Length(arr));
Readln;
end.
Compile the C code using, for example, the Borland C compiler like this:
bcc32 -c testarray.c
And the output is:
1.00000000000000E+0000 2.00000000000000E+0000 3.00000000000000E+0000 4.20000000000000E+0001 6.66000000000000E+0002
Note that I linked to the C code statically because that was easier for me. Nothing much changes if you put the C code in a DLL.
The conclusion is that the code I gave you in my answer to your previous, and that I repeat here, is correct. That approach succeeds in passing an array from Delphi code to C. It looks like your diagnostics and debugging is in error.
You are only inspecting A[0] so it's hardly surprising that you only see one value. If only you would look at A[1], A[2], ... , A[n-1] you would see that that all the values are being passed correctly. Or perhaps your debugging was carried out on the erroneous declaration of the external function that used TArray<T> as a parameter.
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